UC-NRLF OF THE UNIV FPSITY ASTRONOMY LIBRARY AST! APPENDICES TO VARIOUS NAUTICAL ALMANACS BETWEEN THE YEARS 1834 and 1854. PUBLISHED BY ORDER OF THE LORDS COMMISSIONERS OF THE ADMIRALTY. lonfton : PRINTED BY W. CLOWES & SONS, STAMFORD STREET ; AND SOLD BY JOHN MURRAY, ALBEMARLE STREET. 1851. I ASTRONOMY LIBRARY CONTENTS. Page. 1. New Tables for computing the Occultations of Jupiter's Satellites by Jupiter, the transits of the Satellites and their shadows over the disc of the Planet, and the positions of the Satellites with respect to Jupiter at any time. By Mr. W. S. B. Woolhouse, Head Assistant on the Nautical Almanac Establishment. ------- \ 2. On the Computation of an Ephemeris of a Comet from its Elements. By Mr. W. S. B. Woolhouse. 40 3. Comparison of results deduced from M. Burckhardt's and M. Damoiseau's Lunar Tables, for the Year 1834. 49 4. On Eclipses. By Mr. W. S. B. Woolhouse. 53 5. On the Calculation of the Perturbations of the small Planets and the Comets of short period. By Gr. B. Airy, A.M., Plumian Professor of Astronomy and Experimental Philosophy in the University of Cambridge. - - 149 6. On the determination of the Longitude from an observed Solar Eclipse or Occultation. By W. S. B. Woolhouse, Head Assistant on the Nautical Almanac Establishment. - - - - - - -172 7. On the Elements of the Orbit of Halley's Comet, at its appearance in the years 1835 and 1836. By Lieut. W. S. Stratford, R.N., Super- intendent of the Nautical Almanac. --------185 8. On the Perturbations of Uranus. By J. C. Adams, Esq., M.A., F.R.A.S., Fellow of St. John's College, Cambridge. - - - 265 9- On the Correction of a Longitude determined approximately by the observation of a Lunar Distance. By the Rev. J. Challis, M.A., F.R.S., F.R.A.S., Plumian Professor of Astronomy in the University of Cambridge. - 295 ADVERTISEMENT. AS,.. . THE Papers contained in the present Volume consist of the Appendices which have appeared in various NAUTICAL ALMANACS between the years 1834 and 1854, and are now collected together for separate publication, as being not only a more con- venient form for reference, but the means of giving to them a more permanent existence. W. S. STRATFORD, Lieutenant R.N ., Superintendent of the Nautical Almanac. Nautical Almanac Office, 3, Verulam Buildings, Gray's Inn, London, June 30, 1851. NEW TABLES FOR COMPUTING THE OCCULTATIONS OF JUPITER'S SATELLITES BY JUPITER, THE TRANSITS OF THE SATELLITES AND THEIR SHADOWS OVER THE DISC OF THE PLANET, AND THE POSITIONS OF THE SATELLITES WITH RESPECT TO JUPITER AT ANY TIME. BY MR. W. S. B. WOOLHOUSE, HEAD ASSISTANT ON THE NAUTICAL ALMANAC ESTABLISHMENT. CONCISENESS and simplicity are considerations which ought principally to be looked to in determining on any particular mode of calculation, and most especially when an extensive series of the same quantity has to be computed, as in the determinations which form the subject of the present paper. I am not aware of the publication of any practical methods of determining the particulars relating to the Satellites of Jupiter, given in the Nautical Almanac, except in a paper by M. DELAMBRE, printed in the Con- naissance des Terns for 1808. This ingenious paper is for the most part confined to the Configurations of the Satellites; and the method has been subsequently adopted, up to the present time, by the computers of the Connaissance des Terns. The roughness of the plan pursued and the variety of operations which it involves, have however induced me to extend my inquiry to the Configurations as well as the Contacts, all of which I have here endeavoured to reduce, in practice, to the most simple considerations, with a view of saving labour in the future computation of these interesting and multi- plied phenomena. GEOCENTRIC SUPERIOR CONJUNCTION. We shall proceed first to determine the time of the geocentric conjunction of a satel- lite, which takes place near to any proposed heliocentric conjunction, or middle of the eclipse in the shadow of Jupiter. Let, on the day of heliocentric conjunction, (G) = 2 's geocentric longitude, j (H) = 2 's heliocentric longitude, > at mean noon, expressed in degrees. (G) (H) = P = % 's annual parallax, J (G'), (H'), P',=: the same quantities at the following mean noon. (G ') - (G) = (HO - (H) = S(H) daily differences. r = mean time of heliocentric <5 , expressed in hours. t = mean time of geocentric 6 , expressed in hours. R = mean synodic revolution of the satellite, expressed in hours. NAUTICAL ALMANAC, 1835. APPENDIX. (2nd Edition.) 2 New Tables for computing the Occupations, Then the parallax at the time of geocentric conjunction = P -\ -- SP; and the time of moving over this, with the satellite's heliocentric synodic motion, which may be assumed the same as that of the mean, will be This must correspond with the interval from heliocentric to geocentric conjunction ; therefore, by equating it with t r and solving for t, we get R SP !Tf $~D > XV O x 360 24 1 . 360 24 1 R SP 360 24 t or, omitting $ P in the denominator, which is very small compared with 5 K RT* ~~ -tt According to DELAMBRE, the values of R for the four satellites are b R t = 42 -476651 R 2 85 '298258 Ra = 171 '993285 R 4 = 402 '085284 which substituted in the above, the respective formulae for the several satellites come out as follows : Geo. 6 < l = {r + 0-1179907 P} { 1 +'0049 SP } ] Geo. 6 ) 2 sin 2 2/ = sin 2 ' = ^ =r -j sin 2 = ( 1 X) sin 2 /. sm 2 r=(l X) sin 2 (!+>>) 2 sin 2 2/=:(l X) sin 2 -(l +p) 2 sin 2 (X + /S) sin (X-f/3) sinX + siny8 . assume := (!+/>). - = (1 +p) - r - , neglecting sin a sin the second powers of the small arcs X and ft which are insignificant, and ^c^O-X-^) The time of describing this angle x, or the semiduration of the occultation or transit, is therefore Here the small number X need only be retained for the fourth satellite, and for this only near the limits, viz. when N<1200 or >2800. The semiduration should then N be computed strictly from this expression, using = -- 2, But when N falls without these limits, X may be neglected, and the table used with argument N. Transits, fyc. of Jupiter s Satellites. By taking H = 46'241 0-01384 (1750) I = 74-969 + 0-67752 (t 1750) K = 187 -493 + 2-53988 (1750) L =256-68 +12-03424 (1750) the theory of LAPLACE gives the latitudes of the satellites above the orbit of Jupiter, according to the following expressions, in which C t , C 2J < 35 o denote the longitudes of the satellites, which at conjunction will correspond with that of the planet. X l = + 3 "0894 sin ( Ci + H) -0095 sin (Ci + L) -0023 sin ( < l + K) X 2 = + 3 -0726 sin ( ( a + H) -4636 sin ( C 2 + L) 0-0337 sin (< a + K) -0058 sin ( ( 2 + I ) \ 3 = + 3 -0061 sin ( < 8 + H) V -2054 sin (< 8 + K) 0-0312 sin ( 3 + I ) + -0159 sin (> and the number L of 4 , being of little importance, have been omitted. In Table III of the first satellite '380 has been added to the number H. In Tables III and III* of the second satellite there has been added f H . . . 0*613 to the number < K . . . '006 I L . . . '081 o 700 In Tables III and III a of the third satellite there has been added {H . . . '930 k;;;J-S L . .0 '004 1 -000 And in Tables III and III a of the fourth there has been added f H . . . 1 -858 to the number < I ... '122 IK. .0 -020 2-000 The values of * with the constants thus added are designated the number N 3 so that !*! = &+ '380, ^--2+ '700, N 8 = I +1'000, N 4 = & + 2 '000 The numbers ft and F have been computed by taking z'= 1 18'7 and D==5'203. It is evident, that a transit of the shadow of a satellite would, to an observer at the Sun, be a transit of the satellite itself, and hence the determination of the semiduration of such a transit will be of a similar nature ; we have only to use the heliocentric lon- gitude of Jupiter for % instead of the geocentric, and to omit ft and its correction, because the jovicen trie latitude of the Sun =0. INFERIOR CONJUNCTIONS. The determination of the time of the middle of the transit of the shadow, or the time of the inferior heliocentric conjunction, depends on a different consideration. If the satellite's motion were uniform we should merely have to take the mean of the preceding and following superior heliocentric conjunctions or middles of the eclipses in the shadow of the planet. From an inspection of the arguments we see that, in those of each satellite, C, D, E, and H, I, K, L, including c for the third satellite, are the Transits, fyc. of Jupiter s Satellites. 7 only ones which sensibly vary in the course of a revolution. The arguments H, I, K, L, vary very nearly with the motion of the satellite, and their equations help to reduce the conjunction from the plane of the orbit of the satellite to that of the planet, (see Tables Ecliptiques des Satellites de Jupiter. Par M. DELAMBRE. Paris, 1817, page XVII of the Introduction) ; therefore, from superior to inferior conjunction these arguments will acquire very nearly half a revolution, and their combina- tions 2H, 21, 2K, 2L, H + I, H + K, H + L, K + I, K + L, I + L, will acquire nearly a whole revolution; and, since the equations responding to these arguments depend on the sines of these angles, they will admit of no material variation at inferior, from their values at superior, conjunction. Also, the equations which depend on the arguments D, E, of the first satellite, are too small in themselves to affect any results in a sensible manner. The equations be- longing to the other arguments have, however, irregularities which it will be necessary to take into account in deducing an inferior from the preceding and following superior conjunctions. In the course of a revolution of the satellite, the motions of these arguments will, according to DELAMBRE, be as follow : FIRST SATELLITE. Motion of Argument C (s^^-^)^ '5020 in one revolution. SECOND SATELLITE. Motion of Argument C (==( 2 C 3 )= '50411 D ( = (L 2 y^s) = I'OOl > in one revolution. E(= 7 > the Northern surface of the orbit is visible. ' f N, < -380 1 When J -^ 2 ^ *7 I the Southern surface of the orbit is visible. ( N 3 < 1-000 ( N 4 < 2-000 J To find the co-ordinates of the satellite at any time, let be the synodic angle described round the planet from its superior geocentric conjunction, which is due to the synodic motion in the interval, and xy its co-ordinates referred to the axes of the ellipse, and expressed in equatorial semidiameters of the planet. Then is x r sin 9 y = (rcosfl) s ' assumng 10 New Talks for computing the Occult ations, If x be estimated towards the West, and y towards the North, we have hence in which assumes the same sign as the time from conjunction, viz. negative when before and positive when after. For the ordinates estimated in the same directions, as seen through an inverting telescope, we must change the signs, and therefore have x =: r sin 6 which always takes the same sign as the time from conjunction, or the same sign as the assumed time minus the time of conjunction; and the ordinates y for the four satel- lites will be y .= C7oo-NQ- C7 D - N *) y.= (1-000 M.) C' 000 -**') IS P , $? y,= (2'000-N 4 ) - (3 - 000 D - N '> ; t ; ifcSf: The Tables VI, for each satellite, (pages 35, 36,) furnish the values of x and D for successive intervals of ten minutes from the time of conjunction, and are carried to an extent which will be sufficient to determine the positions of the satellite at the times of its immersion into, and emersion from, the shadow of the planet. With the number N, which is the argument of the semiduration of the occultation, and the divisor D found from these Tables, the formula as above presents a very simple computation of the ordinate y, which will always come out with its proper sign, according to the inverted position of the satellite. CONFIGURATIONS. The Table of the elongations of the satellites, at page 39, has been computed, by sup- posing the equatorial semidiameter of Jupiter =3' 7, so as to bring the greatest for the fourth satellite a little within the limit of 100 on each side; and in the Table, 100 is applied to each of them, in order to make them positive, and avoid the necessity of laying them off in both directions. O P Q Thus, if P be the place of Jupiter, and PO be made equal to 100, on a convenient scale, the elongations, as taken from the Table, must be measured from the line towards the right-hand. The argument of the Table is the time from the pre- ceding superior geocentric conjunction, expressed in decimal parts of the time of its synodic revolution, or in decimal parts of the circumference. If 7 denote the argu- ment, and r the mean distance of the satellite, its elongation to the eastward will be = 3 7 r sin (7.360); but by assuming the inverted appearance it will be to the Transits, $*c. of Jupiter s Satellites. 11 westward of the planet. The Table contains therefore 100 + 3'7 r sin (7.360) To find the elongation of the satellite at any time it will be necessary to know the time from the preceding geocentric conjunction, expressed in parts of the geocentric synodic revolution of the satellite at that time ; and this can very readily be effected by means of Table VII, (pages 37 and 38,) which gives the decimal parts of the mean synodic revolution, answering to any number of hours or minutes, for each satellite. Let G denote the time of the geocentric conjunction, which takes place near to the commencement, and G' the time of that which takes place near to the termination, of the month ; and suppose the number of revolutions which intervene to be n ; and let denote the difference between the interval G' G, and n mean revolutions; so that if R denote the mean and R' the actual revolution of the satellite, we shall have and consequently any time t in parts of R' t t t t] nR -in 1 -. . 1+ nR Or t in parts of R' := -^- ( 1 -- g j In this last expression ( -=- ) and ( -= ) represent the times t and c in parts of \K/ \ R / the mean revolution, and can be taken directly from the Tables, having previously found by comparing the interval G' G with the multiples of the mean revolutions, thus, = (G' G) nearest multiple of revolution. r*t f The divisor -- expresses the number of times the time t is contained in the interval G' G; and if t be one day it will express the number of days in this interval. Hence, the reduction of one day into parts of the true revolution is very easily per- formed as follows : Compare the interval between the geocentric conjunctions with the multiples of the mean revolutions; subtract the nearest multiple, and annex the proper algebraic sign to the small remainder. With this remainder take out the corresponding parts of the mean revolution, and divide the same by the number of days which intervene between 12 New Talks for computing the Occupations, the conjunctions. This quotient will be a correction to be subtracted from the value of 24 hours, in parts of the mean revolution, to get the same in parts of the actual revolution. The value thus found of a day in parts of the revolution of the satellite will serve as a daily difference, in order to deduce, by repeated addition, the arguments on successive days. It will be best to compute for the commencing one, that which is the nearest to the first conjunction, since the interval from conjunction may then, on account of its smallness, be used in parts of the mean revolution without any correction; and we must observe, that when this time is prior to the conjunction, it must be considered as negative, and we must then subtract the argument from 100000 to make it positive; also, in the successive additions of the daily difference, we must reject the units or whole revolutions as they arise. The argument computed on the day nearest to the last conjunction w r ill serve as a check to the addition, and will indicate, by its slight deviation from the series, the degree of accuracy of the work. It is evident that the arguments can be carried back to the previous days by successively subtracting the daily difference and borrowing 100000 when necessary. In taking out the elongations it must be observed, that when the argument is found in the left-hand column the dot is to be placed on the left-hand of the numeral ; and that when the argument is found in the right-hand column the dot must be placed to the right-hand of the numeral ; also, that at the beginning and end of the Table, the satellite is at its greatest elongation from the planet, and consequently stationary. Before the elongations are taken out, however, it will be advisable to look through the times of the eclipses in Jupiter's shadow, w r hich occur in the course of the month, and to note those which will be transpiring at the time for which the configurations are given. When the argument approaches 000 or 500, the elongation in the Table will ap- proach 100, and the satellite will be near to the planet. If the elongation should come within 3 '7, the semidiameter of Jupiter, either in excess or defect of 100, or be between the values 96'3 and 103*7? tne satellite will be If the ordinate y be required it may be computed from the formula y 3 -7 _Ji_ cos e = (3 '43 ) cos (7.360) in which 7 is the decimal argument of the elongation; and the factor (3*43 ) may be regarded as constant for a considerable period. This ordinate y will be the visible latitude of the satellite under the inverted appearance. For the formation of the arguments of semidurations, the values of H, I, K, L, are here subjoined, for the commencements of the years from 1830 to 1850 inclusive. The first one H need only be used to the tenth of a degree, and the others to the nearest degree ; also H, I, K, may be assumed as retaining throughout each year their values at the middle of the year, and L may be formed and used as constant for each month, the consecutive ones differing from each other one degree. Transits, fyc. of Jupiter s Satellites. 13 Year. H I K L 1830 1 2 45 -13 45-12 45 -11 129 -2 129 '8 130 -5 30 7 33 -2 35 '8 139-4 151 -5 163 -5 3 4 5 45 -09 45 -08 45-06 131 -2 131 '9 132-6 38 '3 40 -8 43 -4 175 '5 187-6 199'6 6 7 8 45 '05 45 -04 45 -02 133 -2 133-9 134 '6 45 '9 48 -5 51 -0 211 -6 223 7 235 7 9 1840 1 45 -01 45 'GO 44-98 135 -3 135-9 136-6 53 -5 56-1 58 '6 2477 259-8 271 '8 2 3 4 44-97 44-95 44 '94 137-3 138 -0 1387 6l -2 63 '7 66-2 283 *8 295 '9 307-9 5 6 7 44 -93 44-91 44-90 139-3 140 -0 140 7 68 -8 71-3 73-9 319'9 332-0 344 -0 8 9 1850 44 -88 44-87 44-86 141 -4 142-0 142 '7 76-4 81 -5 356-0 8 'I 20 'I EXAMPLES. Let it be required to compute the superior contacts, or times of immersion and emersion, of the third satellite, behind the disc of Jupiter, near to the time of its eclipse, on Jan. 14, 1835; and also the co-ordinates of the satellite at the times of immersion and emersion of that eclipse, &c. &c. To proceed with this Example, we have the following materials : H = 45-l, 1 = 133, K = 43, L = 200, = 294 & = 98 Middle of Eclipse Jan. 14 d 14 h 43 m 'l, Im. 13 h 29 m '4, Em. 15 h 56 m '8 Jupiter's Geocentric Longitude. o I Diff. Jan. 14 - - 61 54 '4 15 - - 61 52-1 16 - - 61 49 '9 17 - - 61 47'9 18 - - 61 46'2 19 - - 6l 44 '6 20 - - 61 43 '2 21 - - 61 42 -0 22 - - 61 41 'I 2 *3 2'2 2-0 1-7 1 -6 1 -4 1 '2 Jupiter's Heliocentric Longitude. O / Diff. Jan. 14 - - 70 41 '1 " 15 - - 70 46 '4 1 16 - - 70 51 -6 17 - - 70 56 -9 18 - - 71 2*1 19 - - 71 7'4 20 - - 71 12-6 21 - - 71 17 '9 22 - - 71 23 '1 5'2 5'3 5 '2 5-3 5 '2 5'3 5'3 14 New Talks for computing tlie Occupations, And the computations will be as here given : OCCULTATION. Numbers. (G).... (H)... 61 54'4 S(G) 70 41 -1 S(H) -2-3 (G)6l'9 (G) + H 107'0 ... H + 5-3 (G) + I 195 I 1728 12 P. . . . - -8 46'7 SP. .. - 7 '6 (G) + K 105 K 2 p r- - 3 h 49 rn '3 T + 10 -5 (G) + L 262 L 4.' { in time I 22 '3 rp ^p go 174 294 O 196 ft (G 0) 232 F=+6 19 3 Hel. 6 Arg. semidur. N d h ra , . . Jan. 14 14 43 *1 1 T 7720~ P in time , 411*6] f. (TSP). . 1-6 Geo. 6 . 14 10 29 "9 Semidur 1 17 '4 Immersion ...... ...... 14 9 12 '5 . 14 11 47*3 Hence these phenomena take place in this order : Jan - Immersion in . . ) Al -. -. ~ T f Emersion from } tlie shadow of Ju P lter { h m 9 12'5 11 47-3 13 29-4 15 56 '8 and it appears that they will be all visible on the Earth at such places as are free from sun-light, and have the planet sufficiently above the horizon. When an immersion or emersion, with respect to the disc, transpires within the interval between the immersion and emersion of the eclipse, such phase will be enveloped in the shadow, and consequently invisible ; similarly when either phase with respect to the shadow transpires within the duration of the occultation, it will be inter- cepted from the Earth by the interposition of the disc of the planet, and likewise invisible. It is evident, that in these cases two phases will be obscured, viz. one of each phenomenon ; an immersion of one and an emersion of the other. Thus, if the emersion of the occultation takes place in the shadow by its falling within the duration of the eclipse, the immersion of the eclipse will also be hidden behind the disc ; and if the immersion of the occultation takes place in the shadow, the emersion from the shadow will, for the same reason, take place behind the disc ; and this is a very simple and accurate way of determining the visibilities of the phases of these phenomena with reference to the Earth generally. In some rare cases, near to the conjunction or opposition of the planet to the Sun, the eclipse will take place wholly behind the disc, when of course neither phase will be visible. Transits, *c. of Jupiter s Satellites. 15 CO-ORDINATES AT ECLIPSE. h m h m Immersion in shadow 13 29 '4 Emersion from shadow 15 56*8 Geocentric 6 1 29 '9 . . . . , , . . . , , 1 29 '9 Time past 6 + 2 59 '5 Time past 6 + 5 26 '9 D = 13 j?= + 2-91 D = 11 Const. . . 1 *000 N 1 720 D. ..13) 720 D 11) 720 55 65 2/ = - '665 y~ '655 Immersion #= + 1*6 1 # = '66 Emersion oc + 2 '91 y^ *65 These serve for the delineation of the two phases, here annexed, as they will appear through an inverting telescope. The next eclipse of the third satellite following the preceding is on Jan. 21, when we have the middle of the eclipse, Jan. 21 d 18 h 44 m *5; and, as before, we compute d h m Geocentric d Jan. 21 14 7 '6 Semiduration 1 1 8 *3 Immersion behind disc 21 12 49 '3 Emersion from disc 21 15 25 '9 Between these two eclipses and occultations an inferior conjunction must take place, and hence a transit both of the satellite and its shadow. For the computation of these we have, in the calculation of the preceding eclipse, c==224, C~802, 0=717, E==523, to find the correction for inferior conjunction, and the work will be as follows : TRANSITS. d h m I. Of the SHADOW. Middle preceding eclipse Jan. 14 14 43 '1 Middle following eclipse 21 18 44 '5 Sum. .36 9 27 '6 c . . 224 gives - '2 ] ^ ,18 4 43 '8 C..802 . . . + 3'9 [corrections - 5 '5 D.. 717 ... - 8'6 E ' * 523 - '6 Inferior heliocentric <5 ....... 18 4 38 *3 Numbers. Jan. 18 (H)=r7l-0 (H) + H= Il6'l . . . H 1679 (H) + I =204 I 12 (H)-f K = 114 K 5 =271 L N 1696 Semidur. 1 20 '0 Ingress of shadow, i . 18 3 18 "3 Egress of shadow. . . 18 5 58 '3 16 New Tables for computing the Occultatlons , II. Of the SATELLITE. Free. geo. 6 .......... Jan. 14 10 Foil. geo. <5 .............. 21 14 7 '6 Sum. ... 36 37 '5 Sum 18 Corr. . 18 '8 5-5 Inferior geo. 6 18 13 '3 Semidur. . 1 17 '8 Semidur. prec. occult. Semidur. foil. Semidur. transit of 1 satellite. . . J h m 1 17-3 1 18 '3 1 17 *8 mean, Ingress of satellite 17 22 55 '5 Egress of satellite 18 1 31 '1 When a continued series is to be computed, as in the formation of page XXI of the Nautical Almanac, it will not be requisite to find the semiduration every time. With the first satellite it will be sufficient to compute the semiduration for the first in each month, and to interpolate the others; with the second, one at the beginning and another about the middle of the month will serve ; and with the third, we may compute for every third conjunction ; but with the fourth satellite it will be necessary to compute it at every conjunction. All these results are in mean astronomical time, and may readily be converted into that of sidereal, in the usual manner. CONFIGURATIONS. In forming the times from conjunction, we may for the first, second, and third satellite, assume our epochs near to the beginning and end of the month ; but for the fourth satellite it will be best to compute them near to each conjunction. As an ex- ample, take the month of January in which they are given at 9 h , mean time; and for the first satellite use the geocentric conjunctions Jan. 2 d 8 h 13 m 7 and Jan. 30 d 15 h 31 m< 7- The times nearest to these conjunctions are Jan. 2 d 9 h and Jan. 30 d 9 h j and we deduce the epochs 'of the distances from conjunction and the daily difference as hereunder. Time. 6 Past 6 = Time 6 d h Jan. 2 9 m d h m 2 8 13 7 h m + 46 '3 = in Parts Epochs. . . 01817 30 9 30 15 31 7 - 6 31 7 = in Parts 15369 or 84631 Interval 28 7 18 '0 Nearest multiple 28 737-6 Interval 28 d '3 ) 770 in Parts (. 10 Parts. 56502 for 24 hours. 27 Corr. to deduct. 56529 daily difference. By using, for the second satellite, the conjunctions Jan. l d O h 51 m '7, Jan. 29 d h 2S m '8, Jan, 28 d 17 h 50 m '8; and for the fourth, .y. for the thirdj Jan< Transits, fyc. of Jupiter s Satellites. 17 Jan. l d 7 h 59 m '2, Jan. I7 d 23 h 33 m '0, and Jan. 34 d l6 h 9 m< 0, we find in the same manner the epochs and daily differences to come out as follow : Jan. 1 29 Jan. 28 SECOND SATELLITE. diff. THIRD SATELLITE. daily diff. 13987 FOURTH SATELLITE. \l ^L 2 daily diff. 06006 34 We hence proceed to fill up the following Table, by first inserting the epochs marked (*), and then applying successively the daily difference. JANUARY, AT 9 HOURS, MEAN TIME. 56329 C t 28169 C 2 13987 3 06006 ( 4 Date. Past 6 Elong. Past 6 Elong. Past 6 Elong. Past 6 Elong. Jan. 1 45288 106- *09541 119 *17196 148 *00252 102 2 *01817 -102 37710 124^ 31183 151- 06258 137 3 58346 89- 65879 71' 45170 116- 12264 .167 4 14875 -117 94048 87 59157 70- 18270 188 5 71404 79- 22217 134 73144 46s 24276 sl96 6 27933 121- 50386 99- 87131 . 60 30282 191- 7 84462 . 82 78555 67 01118 104 36288 173. 8 40991 112- 06724 114 15105 144 42294 145- 9 97520 97 34893 128- 29092 153- 48300 no. 10 54049 95- 63062 75- 43079 123- 54306 74- By carrying forward the successive additions of the daily differences to the distance past d , up to the latter epochs, which must be previously inserted, we shall find, by comparing the number which would come out by the summation with the epoch, the degree of accuracy of the work. Thus, the continued summation for the first satellite would, on the 30th day, give 84629, differing only 00002 from the epoch; the second satellite, on the 29th, would come out 98273, varying only 00014 from the epoch ; the third satellite, on the 28th, would give 94845, differing only 00011 ; and the fourth satellite, on the 18th, would give 02354, differing only 00004. We must start again from these epochs for the remaining days of the month, and for the fourth satellite, we must use the new daily difference. The ten days above shown will be sufficient to illustrate the process; and it will here be only necessary to observe, that the elon- gations are taken out by using the nearest third figure of the argument, and that the dot is placed according to the rule given at page 12. NAUTICAL ALMANAC, 1835. APPENDIX. (2nd Edition.) 18 New Talks for computing the Occultations, In mapping them, which for the Almanac is done on a scale of about 55 to the inch, we have merely to place the scale so that the division of 100 shall bisect the representation of the planet, and then to mark the places of the four satellites by means of their elongations, and lastly to place the distinguishing numeral in its proper position; keeping in mind, to look through the eclipses which occur in the course of the month, for the purpose of indicating such satellites as are immersed in the shadow at the time of the configuration. The following corresponds with the foregoing ten days, and will serve as a specimen. JANUARY 1835. CONFIGURATIONS OF THE SATELLITES OF JUPITER, At 9 h , MEAN TIME. Day of the Month. West. East. O 2- -4 3- 3 I 2- 1- O 3- 1- O 2-O O 1' 2 ! 1ft O 4- 2 3- 10 2'. i-O 3- Before concluding, it will be proper to observe, that the mean distances used in this paper are those which agree better than any other recorded values with the observed greatest semidurations of the eclipses, adopted in the Tables of DELAMBRE. To correspond perfectly with these semidurations they should be 6'00, 9*49, 15'20, 26'39. They are, in fact, not yet well" ascertained, and nothing seems better cal- culated for their accurate determination, as well as of the other elements of the orbits of the satellites, than careful observations of the contacts with the disc of the planet ; and the facilities now afforded in the improved form of the Nautical Almanac will doubtless attract the attention of English observers to this as well as many other important and interesting subjects. Transits, Sfc. of Jupiter's Satellites. 19 FIRST SATELLITE. I. Reduction of 2 's Annual Parallax into Synodic Time. II. CORRECTIONS FOR INFERIOR CONJUNCTION. Argument C, used in preceding Eclipse. Arg. C. Corr. C. Diff. Arg. C. Corr. C. Diff. Degrees. Time. m m m m Q 4-0 '1 5000 -{-0 *0 O h m 0*8 '8 1 o 7-1 100 0-9 '7 5100 0'8 8 2 14 '2 200 1-6 8 5200 i -6 8 3 21 '2 300 2 '4 '7 5300 2'4 '7 4 28 '3 400 3-1 "7 5400 3-1 '7 5 35 '4 500 3'8 6 5500 3'8 6 6 42 '5 600 4 '4 6 5600 4.4 6 7 o 49-6 700 5'0 4 5700 5'0 4 8 56-6 800 5'4 4 5800 5-4 4 9 1 3*7 900 5-8 o 5900 5 '8 *3 10 1 10 '8 1000 6-1 o 6000 6-1 *2 11 1 17'9 1100 6-3 f. *A 1 6100 6-3 (. .4 1 Min. Time. Min. Time. 1200 1300 O 4 6-4 o 6300 O TC 6-4 o ( } 1 6400 6 '3 1 j IT ITX 1-UU O O *2 u-uu *2 '0 30 3'5 1500 6-1 "3 6500 6-1 3 1 1 31 3 "] 1600 5'8 4 6600 5 '8 "4 2 2 32 3'8 1700 5*4 5 6700 5-4 5 3 4 33 3 '9 1800 4-9 5 6800 4-9 6 4 5 34 4 '0 1900 4.4 6 6900 4-3 6 5 6 35 4 '1 2000 3 '8 7 7000 3-7 '7 6 7 36 4-2 2100 3-1 8 7100 3 '0 7 7 4 37 4.4 2200 2 '3 8 7200 2'3 / 8 8 '9 38 4-5 2300 1 '5 8 7300 1 '5 8 9 1 i 39 4-6 2400 H-o-7 8 7400 + o -7 8 10 1 *2 40 4 '7 2500 '1 '8 7500 o-i 7 11 1 a 41 4 '8 2600 0-9 8 7600 0'8 / 8 12 1 4 42 5-0 2700 1-7 *7 7700 1-6 8 13 1 5 43 5-1 2800 2 -4 / 8 7800 2-4 '7 14 1 7 44 5-2 2900 3-2 '7 7900 3-1 '7 15 I 8 45 5 -3 3000 3-9 6 8000 3-8 6 16 I 9 46 5'4 3100 4-5 *5 8100 4.4 5 17 2 o 47 5 '5 3200 5 -0 5 8200 4-9 5 18 2 i 48 5-7 3300 5 -5 4 8300 5'4 4 19 2 2 49 5 -8 3400 5-9 "3 8400 5 -8 3 20 2 4 50 5 '9 3500 6-2 8500 6-1 *2 21 2 8 51 6-0 3600 6-3 J 8600 6-3 22 2 6 52 6-1 3700 6-4 '0 8700 6-4 o 23 2 '7 53 6-3 3800 6-4 I 8800 6-4 1 24 8 54 6-4 3900 6-3 2 8900 6-3 2 25 3 55 6-5 4000 6-1 '3 9000 6-1 3 26 3 a 56 6-6 4100 5 -8 "4 9100 5'8 4 27 3 *2 6-7 4200 5 -4 '5 9200 -5-4 5 28 a 3 58 6-8 4300 4-9 5 9300 4-9 6 29 a 4 59 7 -o 4400 4 4 6 9400 4'3 6 30 a 5 60 7'1 4500 3 '8 '7 9500 3-7 7 4600 3-1 / 9600 3'0 / Factor. 4700 2'4 '7 '8 9/00 2'3 *7 8 f i J = -005 = 200 4800 4900 1-6 0-8 8 '8 9800 9900 1 '5 0-7 8 0*8 5000 + 0-0 10000 + 0'1 Neiv Tables for computing the Occupations, FIRST SATELLITE. III. Number H. Argument (H + Long. ) H+ -u. Number H. H + 2 Number H. H + V Number H. H + 2 Number H. o o o o o 270 042 315 225 141 180 380 45 135 619 271 269 042 316 224 145 1 179 386 46 134 623 272 268 D42 317 223 150 2 1/8 392 47 133 627 273 267 042 318 222 154 3 177 398 48 132 631 274 266 043 319 221 158 4 1/6 403 49 131 635 275 265 043 320 220 163 5 175 409 50 130 639 276 264 044 321 219 167 6 174 415 51 129 643 277 263 044 322 218 172 7 173 421 52 128 646 273 262 045 323 217 177 8 172 427 53 12/ 650 279 261 046 324 216 181 9 171 433 54 126 653 280 260 047 325 215 186 10 1/0 439 55 125 657 281 259 048 326 214 191 11 169 444 56 124 660 282 258 049 327 213 196 12 168 450 57 123 664 283 257 051 328 212 201 13 167 456 58 122 667 284 256 052 329 211 206 14 166 462 59 121 670 285 255 053 330 210 211 15 165 467 60 120 6/3 286 254 055 331 209 216 16 164 473 61 119 676 287 253 057 332 208 221 17 163 479 62 118 678 288 252 058 333 207 227 18 162 484 63 117 681 289 251 060 334 206 232 19 161 490 64 Il6 684 290 250 062 335 205 237 20 160 496 65 115 6s6 291 249 064 336 204 243 21 159 501 66 114 689 292 248 067 337 203 248 22 158 507 67 113 691 293 247 069 338 202 253 23 157 512 68 112 693 294 246 0/1 339 201 259 24 156 517 69 111 695 295 245 0/4 340 200 264 25 155 523 70 no 698 296 244 076 341 199 270 26 154 528 71 109 700 297 243 0/9 342 198 2/6 27 153 533 72 108 702 298 242 082 343 197 281 28 152 539 73 107 703 299 241 084 344 196 287 29 151 544 74 106 705 300 240 087 345 195 293 30 150 549 75 105 707 301 239 090 346 194 298 31 149 554 /6 104 708 302 238 093 347 193 304 32 148 559 77 103 709 303 237 096 348 192 310 33 147 564 78 102 711 304 236 100 349 191 316 34 146 569 79 101 712 305 235 103 350 190 321 35 145 5/4 BO 100 713 306 234 106 351 189 327 36 144 579 81 99 714 307 233 110 352 188 333 37 143 583 82 98 715 308 232 114 353 187 339 38 142 588 83 97 716 309 231 H7 354 186 345 39 141 593 84 96 716 310 230 121 355 185 351 40 140 597 85 95 717 311 229 125 356 184 357 41 139 602 86 94 717 312 228 129 357 183 362 42 138 606 87 93 718 313 227 133 358 182 368 43 137 610 88 92 718 314 226 137 359 181 374 44 136 615 89 91 718 315 225 141 360 180 380 45 135 619 90 718 Transits, 8$c. of Jupiter s Satellites. FIRST SATELLITE. IV. Number ft Arg. 2 of Jupiter. Divisor for Corr. ft' 0-8 ft' -.0 F o 360 360 6 10 350 5 10 350 6 20 340 9 20 340 7 30 330 14 30 330 7 40 320 18 40 320 8 50 310 21 50 310 10 60 300 24 60 300 13 70 290 26 70 290 21 80 280 27 80 280 67 90 270 28 90 270 4-56 10.0 260 27 100 260 19 110 250 26 110 250 11 120 240 24 120 240 8 130 230 21 130 230 6 140 220 18 140 220 g 150 210 14 150 210 5 160 200 9 160 200 4 170 190 5 170 190 4 180 180 180 180 + 4 V. SEMIDURATION. Argument N. N Semidur. N Semidur. N Semidur. h m h m m ooo 760 i 4 *9 130 630 i 7- 9 260 500 9 7 010 750 1 5 '2 140 620 1 8 ' 1 270 490 9 7 020 740 1 5 -5 150 6lO 1 8 ' 9 "' 280 480 9 '8 030 730 1 5'7 160 600 1 8 ' 9 ' 290 4/0 9 -9 040 720 1 6 -0 170 590 1 8 '6 300 460 9 '9 050 710 1 6-2 180 580 1 8 ' 7 310 450 lO'O 060 700 l 6-5 190 570 1 8 '9 320 440 10 -0 o/o 690 i 6 -7 200 560 l 9'0 330 430 10 '1 080 680 1 6 '9 210 550 1 9' i 340 420 10*1 090 6/0 i 7 2 220 540 1 9 '3 350 410 10 'I 100 660 1 7 -4 230 530 l 9*4 360 400 10 '2 110 650 1 7 '5 240 520 1 9 '5 370 390 10 '2 120 640 i 7-7 250 510 1 9*6 380 380 10 '2 130 630 1 7 '9 260 500 l 97 Of For Satellite, use Geo. Long. V and Arg. N = Numb. (H + ft' + -^-) For Shadow, use Hel. Long. % and Arg. N = Numb. H. 22 New Talks for computing the Occultations, SECOND SATELLITE. I. Reduction of 24 's Annual Parallax into Synodic Time. II. CORRECTIONS FOR INFERIOR CONJUNCTION. Arguments C, D, E, used in preceding Eclipse. Arg. C. Cor. C. Diff. Arg.C. Cor. C. Diff. Arg. Cor. D. Cor. E. Arg. Cor.D. Cor. E. Degrees. Time. m 4- i f o m 50(^0 m 4-0-5 m o in m 4- -o 500 m m o h m 100 4'8 3 '8 5100 1 v *J 4 -3 3 -8 10 1 i u o 510 1 o 1 14 *2 3 *8 3 *7 200 8-6 5200 8 '0 u t 20 1 1 520 1 1 2 28 '4 3 '6 3 '"} 300 12-2 5300 11 '7 30 2 1 530 2 1 3 42 *7 3 *4 3 '4 400 15 '6 5400 15 -1 40 2 1 540 2 1 4 56 *9 3 *2 3 '2 500 18 '8 5500 18 -3 50 3 1 550 3 1 5 1 11 *1 600 21 -6 2 '8 5600 21 '2 2 -9 60 3 2 560 3 *2 6 1 25 *3 2 -6 2 '6 7 1 39 '5 700 24 *2 2 '1 5700 23'8 2 '2 70 4 '2 5/0 4 '2 800 26 '3 5800 26 -o 80 5 2 580 5 2 8 1 53 *7 l / 1 '8 9 2 8-0 900 1000 28 -0 29 '3 1 '3 5900 6000 27 '8 29 'I 1 -3 90 100 5 5 *2 590 600 *5 5 *2 *2 10 2 22 *2 '8 *Q 1100 30'1 6100 30-0 w y 110 6 3 6lO 6 3 11 2 36 *4 "4 '4 1200 30 '5 6200 30 *4 120 6 3 620 6 3 Min. Time. Min. Time. 1300 30-3 '2 '6 6300 30*4 o -o *5 130 7 3 630 7 3 1400 29 *7 6400 29 9 140 7 3 640 *7 3 / n / m 1500 28 *6 1 'I 6500 28 '9 i -o 150 / 8 3 650 8 3 1 '0 -2 30 31 7 '1 7 -3 1600 27-1 1 '5 1 '9 6600 27-4 1 '5 1 -9 160 8 3 660 8 3 2 o 5 32 7 '6 1700 25 '2 2 *4 6/00 25 *5 2 '3 170 9 4 670 9 4 1800 22 '8 6800 23-2 180 9 4 680 9 4 3 o 33 7 "8 2 *7 2 *7 4 "9 34 8 -1 1900 20-1 ** / 3 -1 6900 20 '5 * / 2 '9 190 9 4 690 9 4 5 1 2 35 8 -3 2000 17 -o 3 *3 7000 17-6 3 '3 200 9 4 /OO 9 '4 6 I 4 36 8 '5 2100 13-7 3 '5 7100 14 -3 3 -5 210 9 4 710 9 4 7 8 1 7 '9 37 38 8'8 9 '0 2200 2300 10 '2 6-6 3-6 3 -8 7200 7300 10 -8 7-1 3-7 3 -8 220 230 9 9 4 4 720 730 9 9 4 4 2400 4~ 2 *8 7400 4-3-3 240 '9 4 740 9 4 9 i 39 9 '2 3 -8 3 -8 10 11 2 2 4 6 40 41 9*5 9 "7 2500 2600 1 -0 4-9 3-9 3 '7 7500 7600 -0-5 4 -3 3 -8 3 -8 250 260 9 9 4 4 750 760 9 9 4 4 * T 12 2 8 42 10 '0 2700 8-6 ** / 3-6 7700 8 ! 3 -6 270 9 4 770 9 4 13 3 1 43 10 '2 2800 12-2 3 -4 7800 n -7 3 '4 280 9 4 780 9 4 14 3 3 44 10 '4 2900 15 '6 3 -2 7900 15 -1 3 '2 290 9 4 790 9 4 3000 18'8 8000 18 '3 300 9 4 800 9 4 15 3 6 45 10 '7 2 2 -9 16 3 8 46 10 '9 3100 21 -6 ' 2 5 8100 21 '2 2 -5 310 9 4 810 9 4 3200 24 ! 8200 23 '7 320 -9 4 820 9 4 17 4 o 47 11 -1 3300 26 -3 2 '2 8300 25 -9 2 '2 330 8 4 830 8 4 18 4 3 48 11 '4 1 *8 1 '8 3400 28 '1 8400 27 '7 340 8 3 840 8 3 19 -I 5 49 11-6 1 '3 1 '3 20 4 7 50 11 -9 3500 3600 30 -2 '8 8500 8600 29 -o 29 '9 o-9 350 360 8 7 3 3 850 860 8 '7 3 3 21 5 o 51 12 -1 *4 "4 22 5 2 52 12 *3 3700 30 -6 i 3700 30 -3 '2 370 7 3 870 '7 3 3800 30 '5 8800 30 -1 380 6 3 880 6 3 23 5 5 53 12 '6 '5 '5 24 5 *7 54 12 -8 3900 30 -0 1 *1 8900 29 '6 1 'I 390 6 3 890 6 3 25 5 55 13 -0 4000 28 '9 1 '5 9000 28 '5 1 '5 400 6 "2 900 6 2 26 6 *2- 56 13 '3 4100 27 "4 9100 27 -o 1 '9 410 5 2 910 5 2 27 28 6 6 4 6 57 58 13'5 13 "7 4200 4300 25 -5 23 *2 2 '3 2 '7 9200 9300 25 '1 22-8 2 '3 2 *7 420 430 5 4 2 2 920 930 5 4 2 29 30 6 7 9 1 59 60 14 -0 14 -2 4400 4500 4600 20 -5 17-5 Mq 3 *0 3 '2 9400 9500 QfiOO 20 '1 17-1 1 .0 3 -0 3'3 440 450 460 3 3 *2 1 1 940 950 960 3 3 *2 1 1 1 Factor. 4700 > 10-8 3 '5 y uuv 9700 1 O 10 '3 3 *5 470 2 1 970 2 1 f l 4800 7-1 3 '7 3 *8 9800 6-6 3 "8 480 1 1 980 1 1 J ~~ 100 4900 3 '3 3 *8 9900 2'8 3 *8 490 1 o 990 1 o 5000 4-0*5 10000 + i-o 500 4- *o 4-o 1000 '0 '0 Transits, fyc. of Jupiter s Satellites. SECOND SATELLITE. I a . Number X. For correction of mean Synodic Time. Arg. C used in corresponding Eclipse. C, or C 5000. X 2500 2500 5000 019 50 2450 2550 4950 019 100 2400 2600 4900 019 150 2350 2650 4850 018 200 2300 2700 4800 018 250 2250 2750 4750 018 300 2200 2800 4700 017 350 2150 2850 4650 017 400 2100 2900 4600 016 450 2050 2950 4550 016 500 2000 3000 4500 015 550 1950 3050 4450 014 600 1900 3100 4400 014 650 1850 3150 4350 013 700 1800 3200 4300 012 750 1750 3250 4250 on 800 1700 3300 4200 010 850 1650 3350 4150 009 4i 900 1600 3400 4100 008 950 1550 3450 4050 007 1000 1500 3500 4000 006 1050 1450 3550 3950 005 1100 1400 3600 3900 004 1150 1350 3650 3850 002 1200 1300 3700 3800 001 1250 1250 3750 3750 000 24 New Tables for computing the Occultatiom, SECOND SATELLITE. III. Number H. Argument (H + Long. If. ) Number Number Number Number H + 2 H. H + 2 H. + V H. H + H. o 270 078 315 225 235 180 613 45 135 991 271 269 078 316 224 242 1 179 622 46 134 998 272 268 078 317 223 248 2 178 632 47 133 1004 273 267 079 318 222 255 3 177 641 48 132 1010 274 266 079 319 221 262 4 1/6 650 49 131 1017 275 265 080 320 220 269 5 175 660 50 130 1023 276 264 081 321 219 276 6 174 669 51 129 1029 277 263 082 322 218 284 7 173 678 52 128 1034 278 262 083 323 217 291 8 172 687 53 127 1040 279 261 085 324 216 299 9 1/1 696 54 126 1046 280 260 086 325 215 306 10 170 706 55 125 1051 281 259 088 326 214 314 11 169 715 56 124 1056 282 258 090 . 327 213 322 12 168 724 57 123 1061 283 257 092 328 212 330 13 167 733 58 122 1066 284 256 094 329 211 338 14 166 742 59 121 1071 285 255 096 330 210 346 15 165 751 60 120 1076 286 254 099 331 209 354 16 164 760 61 119 1081 287 253 101 332 208 362 17 163 769 62 118 1085 288 252 104 333 207 370 18 162 778 63 117 1090 289 251 107 334 206 379 19 161 737 64 116 1094 290 250 110 335 205 387 20 160 796 65 115 1098 291 249 114 336 204 396 21 159 805 66 114 1101 292 248 117 337 203 404 22 158 813 67 113 1105 293 247 121 338 202 413 23 157 822 68 112 1109 294 246 125 . 339 201 421 24 156 830 69 111 1112 295 245 128 340 200 430 25 155 839 70 no 1116 296 244 132 ' 341 199 439 26 154 847 71 109 1119 297 243 136 .342 198 448 27 153 856 72 108 1122 298 242 141 343 197 457 28 152 864 73 107 1125 299 241 145 344 196 466 29 151 872 74 106 1127 300 240 150 345 195 475 30 150 880 /5 105 1130 301 239 155 346 194 484' 31 149 888 76 104 1132 302 238 160 347 193 493 32 148 896 77 103 1134 303 237 165 348 192 502 33 147 904 78 102 1136 304 236 1/0 349 191 511 34 146 912 79 101 1138 305 235 175 350 190 520 35 145 920 80 100 1140 306 234 180 .351 189 529 36 144 927 81 99 1141 307 233 186 352 188 539 37 143 935 82 98 1143 308 232 192 353 187 548 38 142 942 83 97 1144 309 231 197 .354 186 557 39 141 950 84 96 1145 310 230 203 355 185 566 40 140 957 85 95 1146 311 229 209 356 184 576 41 139 964 86 94 1147 312 228 216 357 183 585 42 138 971 87 93 1147 313 227 222 358 182 594 43 137 978 88 92 1148 314 226 228 359 181 604 44 136 984 89 91 1148 315 225 235 360 180 613 45 135 991 90 1148 Transits, fyc. of Jupiter s Satellites. SECOND SATELLITE. III a . Numbers K and L. IV. Number ft Arguments K.+ If. and L + If. . Arg. & of Jupiter. Divisor for Corr. ft' Com. Arg. K L 0-8 # V-0 F i , 270 12 162 360 360 6 280 260 12 160 10 350 8 10 350 6 290 250 11 157 20 340 15 20 340 7 300 240 11 151 30 330 22 30 330 7 310 230 10 143 40 320 28 40 320 8 320 220 10 133 50 310 34 50 310 10 330 210 9 121 60 300 38 60 300 13 340 200 8 109 -70 290 41 70 290 21 350 190 7 95 80 280 43 80 280 -67 180 6 81 90 270 44 90 270 + 56 10 170 5 67 100 260 43 100 260 19 20 160 4 53 110 250 41 110 250 11 30 150 3 41 120 240 38 120 240 8 40 140 2 29 130 230 34 130 230 6 50 130 2 19 140 220 28 140 220 5 60 120 1 11 150 210 22 150 210 5 70 no 1 5 160 200 15 160 200 4 80 100 2 170 190 8 170 190 4 90 180 180 180 180 + 4 V. SEMIDURATION. Argument N. N Semidur. N Semidur. N Semidur. N Semidur. 020 1380 h m 1 4-7 190 1210 1 15 '9 360 1040 h m 1 23 '0 530 870 h m 1 27-0 030 1370 1 5 '5 200 1200 1 16 '4 370 1030 1 23 '3 540 860 1 27 -l 040 1360 1 6-3 210 1190 1 16 '9 380 1020 1 23 '6 550 850 1 27 -2 050 1350 1 7'1 220 1180 1 17-4 390 1010 1 23 '9 560 840 1 27 -4 060 1340 1 7'8 230 1170 l 17*9 400 1000 1 24 '2 570 830 1 27-5 070 1330 1 8 '5 240 1160 1 18 '3 410 990 1 24 '4 580 820 1 27 -6 080 1320 1 9'2 250 1150 1 18 '8 420 980 1 24 "J 590 810 l 277 090 1310 1 9'9 260 1140 1 19'2 430 970 1 25-0 600 800 1 27 '8 100 1300 10 -6 270 1130 1 19*7 440 960 1 25 '2 6lO 790 1 27-9 no 1290 11 '2 280 1120 1 20 '1 450 950 1 25 '4 620 780 1 28 '0 120 1280 11 '9 290 1110 1 20 '5 460 940 1 25 7 630 770 1 28 -0 130 1270 12'5 300 1100 1 20 '9 470 930 1 25 '9 640 760 1 28 'I 140 1260 13 '1 310 1090 1 21 '2 480 920 1 26 '1 650 750 1 28 'I 150 1250 13-7 320 1080 1 21 '6 490 910 1 26 '3 660 740 1 28-2 160 1240 14-3 330 1070 1 22 '0 500 900 1 26 '5 670 730 1 28 '2 170 1230 14-8 340 1060 1 22 '3 510 890 1 26-6 680 720 1 28 '2 180 1220 1 15 '4 350 1050 1 22'6 520 880 1 26'8 690 710 1 28 '2 190 1210 1 15 '9 360 1040 1 23 '0 530 8/0 1 27 -0 700 700 1 28 '2 For Satellite, use Geo . Long. % and Arg. N = Numb. (H + K + L +/8'+ -) F For Shadow, use Bel. Long. If. and Arg. N = Numb. (H + K + L) New Tables for computing the Occupations, THIRD SATELLITE. I. Reduction of 1L 's Annual Parallax II. CORRECTIONS FOR INFERIOR CONJUNCTION. Arguments c, C, D, E, used in preceding Eclipse. into Synodic Time. Arg. Corr. c. COIT. C. Corr. D. Corr. E. Arg. Corr. c. J Corr. C. Corr.D. Corr. E. Degrees. Time. m m m m m m m m o 4-0 '4 *2 4-0 '1 4~o *o 500 4-0 '2 4-0 *2 '0 1 h m 28 '7 10 l^ V 1 0*5 0'5 1 v A 0-6 0-3 510 -j- \j f> 0'3 0'5 0'6 0'3 20 0*6 0*7 1 '2 0-5 520 0'4 o *7 1 '2 0'5 2 57 "3 3 1 26 '0 30 0-6 1 *0 i '7 0'8 530 '5 1 '0 1-7 0'8 4 1 54 '7 40 0-7 1 '3 2'2 I'O 540 0'6 1 '3 2 '2 1 '0 50 0*7 1*5 2 '8 1 '2 550 0'6 1'5 2 '8 1*2 5 2 23 *3 6 2 52 *0 60 0*7 1*7 3 '3 1 '5 560 0-6 i*7 3 '3 1 '5 7 3 20 '7 70 o*7 2*0 3 '8 1-7 570 0-7 2'0 3 '8 1*7 8 3 49 *3 80 0*7 2*2 4 '3 1-9 580 0-7 2 '2 4 '3 1-9 9 4 18 *0 90 0'7 2*4 4*8 2 '1 590 0-7 2 '4 4 '8 2 '1 10 4 46 '7 100 0-7 2*6 5 '2 2 '3 600 0-7 2'6 5 '2 2 '3 110 0-7 2*8 5*7 2 '5 6lO 0*7 2 '8 5 '7 2*5 1 1 5 15 *3 120 0-6 3 '0 6'1 2-7 620 0-7 3'0 6'1 2*7 Time. Min. Min. Time. 130 0-6 3*2 6*4 2-9 630 0-7 3 '2 6 '4 2*9 140 0'6 3 *4 6 '8 3 *0 640 0*7 3 *4 6 '8 3 *0 m 0*0 30 m 14 '3 150 0'5 3 '5 7'l 3 '2 650 / 0-6 3 '5 3 *2 1 5 31 14 '8 160 0'4 3 '6 7*4 3'3 660 0-6 3'6 7'4 3 *3 2 1 *0 32 15 '3 170 0'3 3*7 7'7 3 '4 670 0*5 3'6 7'7 3 *4 3 1 4 33 15*8 180 '2 3*8 8 *0 3-5 680 *4 3'8 8 '0 3 '5 4 1 '9 34 16 '2 190 4-o ! 3*9 8*2 3'6 690 0*4 3-9 8 '2 3'6 5 8 4 35 16*7 200 O'O 4*0 8 *4 3-7 700 0'3 4'0 8 '4 3'7 6 2 '9 36 17*2 210 O'l 4*1 8*5 3 '8 710 '2 4 '1 8 '5 3 '8 7 3 3 37 17*7 220 '2 4 *1 8'6 3 '8 720 + 0'1 4'1 8'6 3 '8 8 3 8 38 18 *2 230 0*3 4*1 8 '7 3-9 730 '0 4 '1 8-7 3-9 9 4 3 39 18 *6 240 0*4 4 *1 8 '8 3-9 740 O'l 4 '1 8 '8 3-9 10 4 8 40 19 'l 250 *5 4 *1 8 '8 3-9 750 0'2 4 '1 8 '8 3'9 11 5 3 41 19 '6 260 0*5 4*1 8 '8 3-9 760 0'2 4 '1 8'8 3'9 12 Jt 42 20 '1 270 0*6 4*1 8-7 3-9 770 0'3 4*1 8 '7 3-9 13 6 .0 43 20 '5 280 0-7 4*0 8'6 3 *8 780 0'3 4'0 8 '6 3 '8 14 6 '7 44 21 '0 290 0-7 4'0 8 '5 3 -8 790 '4 4 '0 8 '5 3'8 15 7 '2 45 21 '5 300 0'8 3'9 8*4 3-7 800 0'4 3-9 8 '4 3-7 16 7 6 46 22 '0 310 0'8 3'8 8 '2 3'6 810 0'5 3'8 8 '2 3-6 17 8 i 47 22 '5 320 0-9 3-7 7'9 3 '5 820 '5 3 '7 7'9 3 '5 18 8*6 48 22 *9 330 0-9 3'6 7'7 3*4 830 0'5 3-6 7*7 3 '4 19 9*1 49 23'4 340 0-9 3*4 7 -4 3 '3 840 0'5 3 *4 7'4 3 '3 20 9 '6 50 23 '9 350 0-9 3 '2 7-1 3 '1 850 0'5 3 '2 7i 3 '1 21 10 '0 51 24*4 360 0'9 3*1 6'7 3 -0 860 0'5 3'1 6'7 3'0 22 10 '5 52 24 '8 370 0-9 2*9 6*4 2 '8 870 0-5 2-9 6 '4 2 '8 23 11 o 53 25 '3 380 0*8 2-7 6-0 2*7 880 *4 2-7 6-0 2-7 24 11 5 54 25 '8 390 0'8 2 '5 5 '6 2 '5 890 0*4 2 '5 5 '6 2 '5 25 ll o 55 26 '3 400 0-7 2 '3 5 *1 2'3 900 0'3 2'3 5 '1 2 '3 26 12 '4 56 26 '8 410 0-6 2*1 4*7 2 *1 910 '3 2 '1 4'7 2 '1 27 28 12 '9 13*4 57 58 27'2 420 430 0'5 0*4 1 '8 1-6 4 *2 3-7 1 *8 920 930 0-2 o-i 1 '8 1'6 4 '2 3-7 1 *8 1'6 29 13 '9 59 28 '2 440 '3 1 '4 3 '2 1 *4 940 O'l 1 *4 3 '2 1 '4 30 14'3 60 28 '7 450 460 0'2 0*0 1 '1 0*Q 2*7 2*1 1 *2 1/\ 950 C\f\ f\ O'O 1 '1 O 2-7 1 '2 1 *0 Factor. 470 m '1 o 0-6 1 , u 0-7 you 970 '2 U o 0-6 1-6 0*7 1 480 4-0 *i 0'3 1 '1 0'5 980 0*3 0'3 1 '1 0'5 / = 02 n 50 490 0*2 O'l 4-0 '5 0'2 990 -3 0'5 0'2 500 4-0-2 4-0'2 o-i 4-0 *o 1000 4-0 '4 0'2 4-0*1 O'O Transits, $c. of Jupiter s Satellites. 27 THIRD SATELLITE. III. Number H. Argument (H + Long. % ) Number Number Number Number + H. + H. + H. H + ^ H. o o o 2/0 096 315 225 340 180 930 45 135 1520 271 269 096 316 224 350 1 179 9-15 46 134 1530 272 268 096 317 223 361 2 178 959 47 133 1540 273 267 097 318 222 372 3 177 97-i 48 132 1550 274 266 098 319 221 383 4 176 988 49 131 1560 275 265 099 320 220 394 5 175 1003 50 130 1569 2/6 264 100 321 219 405 6 174 1017 51 129 1578 277 263 102 322 218 416 7 173 1032 52 128 1587 278 262 104 323 217 428 8 172 1046 53 127 1596 2/9 261 106 324 216 440 9 171 1061 54 126 1605 280 260 109 325 215 452 10 170 1075 55 125 1613 281 259 111 326 214 464 11 169 1089 56 124 1622 282 258 114 327 213 476 12 168 1104 57 123 1630 283 257 117 328 212 488 13 167 1118 58 122 1637 284 256 120 329 211 500 14 166 1132 59 121 1645 285 255 124 330 210 513 15 165 1146 60 120 1652 286 254 128 331 209 526 16 164 1160 6l 119 1660 287 253 132 332 208 538 17 163 1174 62 118 1667 288 252 137 333 207 551 18 162 1188 63 117 1673 289 251 141 334 206 564 19 161 1202 64 116 1680 290 250 146 335 205 577 20 160 1215 65 115 1686 291 249 151 336 204 591 21 159 1229 66 114 1692 292 248 157 337 203 604 22 158 1243 67 113 1698 293 247 162 338 202 617 23 15/ 1256 68 112 1703 294 246 l6s 339 201 631 24 156 1269 69 111 1709 295 245 174 340 200 645 25 155 1283 70 no 1714 296 244 180 341 199 658 26 154 1296 71 109 1719 297 243 187 342 198 672 27 153 1309 72 108 1723 298 242 193 343 197 686 28 152 1322 73 107 1728 299 241 200 344 196 700 29 151 1334 74 106 1732 300 240 208 345 195 714 30 150 1347 75 105 1736 301 239 215 346 194 728 31 149 1360 76 104 1740 302 238 223 347 193 742 32 148 1372 77 103 1743 303 237 230 348 192 756 33 147 1384 78 102 1746 304 236 238 349 191 771 34 146 1396 79 101 1749 305 235 247 350 190 785 35 145 1408 80 100 1751 306 234 255 351 189 799 36 144 1420 81 99 1754 307 233 264 352 188 814 37 143 1432 82 98 1756 308 232 273 353 187 828 38 142 1444 83 97 1753 309 231 282 354 186 843 39 141 1455 84 96 1760 310 230 291 355 185 857 40 140 1466 85 95 1761 311 229 300 356 184 872 41 139 1477 86 94 1762 312 228 310 357 183 886 42 13* 1488 87 93 1763 313 227 320 358 182 901 43 137 1499 88 92 1764 314 226 330 359 181 915 44 136 1510 89 91 1764 315 225 340 360 180 930 45 135 1520 90 1764 New Tables for computing the Occultations, THIRD SATELLITE. III 1 . Numbers I, K, and L. IV. Number ft Arguments I + 2, K + 2X> L + If.. Arg. $, of Jupiter. Divisor for Corr. ft' Com. Arg. i K L & ft' -0 F + ~ o o 270 18 114 360 360 6 280 260 18 113 10 350 12 10 350 6 290 250 17 111 20 340 24 20 340 7 300 240 16 106 30 330 35 30 330 7 310 230 16 101 1 40 320 45 40 320 8 320 220 15 94 1 50 310 54 50 310 10 330 210 13 86 2 60 300 61 60 300 13 340 200 12 76 2 70 290 66 70 290 21 350 190 11 67 3 80 280 69 80 280 67 180 9 57 4 90 2/0 70 90 270 + 56 10 170 7 47 5 100 260 69 100 260 19 20 160 6 38 6 110 250 66 110 250 11 30 150 5 28 6 120 240 61 120 240 8 40 140 3 20 7 130 230 54 130 230 6 50 130 2 13 7 140 220 45 140 220 5 60 120 2 8 8 150 210 35 150 210 5 70 no 1 3 8 160 200 24 160 200 4 80 100 1 8 170 190 12 170 190 4 90 8 180 180 180 180 + 4 :; Transits, fyc. of Jupiter s Satellites. THIRD SATELLITE. V. SEMIDURATION. Argument N. N Semidur. N Semidur. N Semidur. 000 2000 h m '0 340 1660 h m 1 23 '7 680 1320 h m 1 45 '6 010 1990 15 '7 350 1650 1 24 '7 690 1310 1 46 '0 020 1980 22 *2 360 1640 1 25 '6 700 1300 1 46-3 030 1970 27 '1 3/0 1630 1 26-6 710 1290 1 46 '7 040 I960 31 '2 380 1620 1 27*5 720 1280 1 47*0 050 1950 34 '8 390 1610 1 28 '3 730 1270 1 47*3 060 1940 38 '0 400 1600 1 29'2 740 1260 l 47 -6 070 1930 40 '9 410 1590 1 30-0 750 1250 1 47-9 080 1920 43 '7 420 1580 1 30-8 760 1240 1 48 '2 090 1910 46 '2 430 1570 1 31 '6 770 '1230 1 48 '5 100 1900 48'6 440 1560 1 32 *3 780 1220 l' 48 '7 110 isgo 50 '8 450 1550 1 33 '1 790 1210 1 49-0 120 1880 52'9 460 1540 1 33 *8 800 1200 1 49*2 130 1370 55 '0 4/0 1530 1 34 '5 810 1190 1 49-4 140 I860 56'9 480 1520 1 35 '2 820 1180 1 49 '6 150 1850 58 '7 490 1510 1 35-9 830 1170 1 49 '8 160 1840 1 0'5 500 1500 1 36 '5 840 1160 1 50 '0 170 1830 1 2'2 510 1490 1 37 '2 850 1150 1 50'2 180 1820 1 3'8 520 1480 1 37*8 860 1140 1 50'4 190 1810 1 5'4 530 1470 1 38 '4 870 1130 1 50-5 200 1800 l 6-9 540 1460 1 39-0 880 1120 1 50*7 210 1790 1 8 '3 550 1450 1 39*5 890 1110 1 50 '8 220 1780 1 9*7 560 1440 1 40-1 900 1100 1 50-9 230 1770 1 11 '1 570 1430 1 40 '6 910 1090 1 51 -0 240 1760 1 12 '4 580 1420 1 41 '2 920 1080 1 51 ! 250 1750 1 13-7 590 1410 1 41 '7 930 1070 1 51 '2 260 1740 1 15 *0 600 1400 1 42'2 940 1060 1 51 '2 270 1730 1 16-2 610 1390 1 42 '6 950 1050 1 51 '3 280 1720 1 17'4 620 1380 1 43'1 960 10-10 1 51-4 290 1710 1 18 '5 630 1370 1 43 '6 970 1030 1 51 '4 300 1700 1 19 *6 640 1360 1 44 '0 980 1020 1 51 '4 310 1690 1 20 '7 650 1350 1 44 '4 990 1010 1 51'5 320 1680 1 21 *7 660 1340 1 44 '8 1000 1000 1 51 '5 330 1670 1 22'7 670 1330 1 45 '2 340 1660 1 23 '7 680 1320 1 45-6 of For Satellite, use Geo. Long. % and Arg. N = Numb. (H + I + K + L + '+-jr) For Shadow, use Hel. Long. % and Arg. N = Numb. (H + 1 + K + L) 30 New Talks for computing the Occupations, FOURTH SATELLITE. I. Reduction of 2 's Annual Parallax into Synodic Time. II. CORRECTIONS FOR INFERIOR CONJUNCTION. Arguments C, D, E, used in preceding Eclipse. Arg. C. Cor. C. Diff. Arg. Cor. D. Cor. E. Arg. Cor. D. Cor. E. Degrees. Time. -4- h m m m m m m 5000 1 *3 o *0 500 4-0 '0 4- *3 Q 7'0 r 1 i 7 -o 100 5100 8'3 / v 6-9 10 "2 2 510 '2 3 2 2 14 '0 200 5200 15*2 6 *9 20 0'3 2 520 0'3 3 300 5300 22'1 30 '5 2 530 O'o 3 3 3 21 *0 6 8 4 4 28 '1 400 5400 28 '9 6 '6 40 0-7 o 540 0-7 3 500 5500 35'5 50 '8 2 550 0-8 3 5 5 35 i 6 *6 6 6 42 *1 600 5600 42 ! 6 '3 60 1 '0 3 56o 1 -0 3 7 7 49'1 700 5700 48*4 6 '2 70 1 '1 3 5/0 1 '1 3 800 5800 54*6 80 1 '3 3 580 1 '3 3 8 8 56 *1 6 *o 9 10 3 ] 900 5900 1 0'6 5 '7 90 1 '4 3 590 1 '4 3 1000' 6000 1 6 '3 " 1 100 1 '5 3 600 1 '5 3 10 11 10 "1 5 *4 1100 6100 l 11 -7 110 i -7 3 6lO 1 '7 2 11 12 17 '2 1200 6200 l 16 *9 5 '2 1 9O 1 *B q 620 1 t( 3 9 Min. Time. Min. Time. 1300 6300 1 21 '8 4 '9 4.x i \) 130 1 9 1-9 o 3 630 1 O 2 1400 6400 1 26 '3 o 140 2 "0 3 640 2 *0 *2 m 0*0 30 m 33'5 1500 6500 1600 6600 1 30 '5 1 34*4 4 '2 3 '9 150 160 2 '2 3 3 650 660 2 '1 2'2 2 1 1 1 31 34 *6 3 *4 2 2*2 32 35 '7 1700 6700 1 37'8 170 2 '3 3 6/0 2*3 1 3 3 4 33 36-9 1800 6800 1 40*9 2 *7 180 2 '4 3 680 2 '4 1 4 4 5 34 38 *0 1900 6900 - 1 43 '6 ** / 2 '3 190 2 *5 3 690 2'5 1 5 6 6 35 39'1 2000 7000 1 45-9 1 -9 200 2'5 3 700 2'5 1 6 6 36 40'2 2100 7100 1 47'8 1 *4 210 2 '6 3 710 2-6 + "1 7 7 8 37 41 '3 2200 7200 1 49'2 1 '0 220 2-6 3 720 2-6 o 8 8 "9 38 42 '4 2300 7300 1 50'2 '6 230 2 '6 3 730 2-6 o 9 10 l 39 43*6 2400 7400 va 60'8 *1 240 2-6 3 740 2-6 o 10 11 2 40 44 *7 2500 7500 1 50 '9 *3 250 2-6 3 750 2-6 o 11 12 '3 41 45 '8 2600 7600 1 50'6 o *7 260 2-6 2 760 2'6 o 12 13 4 42 46 '9 2700 7700 1 49 '9 1 *2 270 2-6 2 770 2-6 o 13 14 5 43 48 '0 2800 7800 1 48 '7 l -6 280 2-6 2 780 2-6 o 14 15 6 44 49*1 2900 7900 i 47-1 2 *0 290 2-6 1 790 2-6 o 15 16 8 45 50 *3 3000 8000 1 45 '1 2 '4 300 2 *5 1 800 2'5 o 16 17 46 51 4 3100 8100 1 42 '7 2 *9 310 2-5 "1 810 2 '5 o 18 19*0 20 '1 47 48 52'5 53 '6 3200 8200 3300 8300 1 39'8 1 36 '6 3'2 3-6 320 330 2'4 2-3 820 830 2'4 2'3 o o 19 21 2 49 54 '7 3400 8400 1 33 '0 4 "0 340 2 '2 840 2'2 o 20 21 22 23 3 5 50 51 55-9 57 *o 3500 8500 3600 8600 1 29 '0 1 24' '6 4.4 4 '6 350 360 2 '0 + 'I 1 850 860 2 *1 2 *0 o o 22 24 6 52 58 '1 3700 8700 1 20 '0 5 *0 370 1 *9 1 870 1 *9 o 3800 8800 1 15 '0 380 1 '8 2 880 1 '8 o 23 25 *^* 53 59 "2 5 '3 24 26 8 54 60 '3 3900 8900 1 9'7 5 '6 390 1-7 2 890 1-7 o 25 27 55 6l '4 4000 9000 1 4'1 5 '8 400 1-6 2 900 1-6 o 26 29*0 56 62-6 4100 9100 58-3 6o 410 1 '4 3 910 1 '4 o 27 28 30'2 31 *3 57 58 63 '7 64-8 4200 9200 4300 9300 52 '3 46 '0 6-3 6 '4 420 430 1 '3 1 '1 3 3 920 930 1 '3 1 'I o o 29 32 4 59 65'9 4400 9400 o 39-6 6 -6 440 1 '0 3 940 1 *0 o 30 33 5 60 67-0 4500 9501) 4600 9600 33 '0 26'3 6-7 6-9 450 460 0-8 0-6 3 3 950 960 0'8 0-6 . Factor. 4700 9700 4800 9800 19 '4 12 '6 6-8 6mf\ 4/0 480 0'5 0*3 3 3 9/0 980 0'5 0'3 . /= '047 4900 9900 5 '7 *9 490 0*2 3 990 *2 . 5000 10000 1*3 7'0 500 '0 + "3 1000 + 0*0 . Transits, fyc. of Jupiter s Satellites. 31 FOURTH SATELLITE. I a . Number X. For correction of mean Synodic Time. Arg. C used in corresponding Eclipse. C X 00 5000 5000 10000 015 100 4900 5100 9900 015 200 4800 5200 9800 014 300 4700 5300 9700 014 400 4600 5400 9600 014 500 4500 5500 9500 014 600 4400 5600 9400 014 700 4300 5700 9300 013 800 4200 5800 9200 013 900 4100 5900 9100 012 1000 4000 6000 9000 012 1100 3900 6100 8900 Oil 1200 3800 6200 8800 on 1300 3700 6300 8/00 010 1400 3600 6400 8600 009 1500 3500 6500 8500 009 1600 3400 6600 8400 008 170Q 3300 6700 8300 007 1800 3200 6800 8200 006 1900 3100 6900 8100 005 2000 3000 7000 8000 005 2100 2900 7100 7900 004 2200 2800 7200 7800 003 .. 2300 2700 7300 7700 002 2400 2600 7400 7600 001 2500 2500 7500 7500 ooo 32 New Tables for computing the captations. FOURTH SATELLITE. III. Number H. Argument (H + Long. 2 ) Number H Number Number Number + % H. + H. + H. H + H. o o 270 550 315 225 933 180 1858 45 135 2783 271 269 550 316 224 949 i 179 1881 46 134 2799 272 268 551 317 223 966 2 178 1904 47 133 2815 273 267 552 318 222 983 3 177 1927 48 132 2830 274 266 553 319 221 100 4 176 1949 49 131 2345 275 265 555 320 220 1017 5 175 1972 50 130 2860 276 264 557 321 219 1035 6 174 1995 51 129 2874 277 263 560 322 218 1053 7 173 2017 52 128 2888 278 262 563 323 21/ 1071 8 172 2040 53 127 2902 279 26l 566 324 216 1089 9 171 2063 54 126 2916 280 260 5/0 325 215 1108 10 170 2085 55 125 2929 281 259 574 326 214 1127 11 169 2108 56 124 2942 282 258 579 327 213 1146 12 168 2130 57 123 2955 283 257 583 328 212 1165 13 167 2152 58 122 2967 284 256 588 329 211 1184 14 166 2174 59 121 2979 285 255 594 330 210 1201 15 165 2196 60 120 2990 286 254 601 331 209 1224 16 164 2218 6l 119 3002 287 253 607 332 208 1244 17 163 2240 62 118 3013 288 252 614 333 207 1264 18 162 2262 63 117 3024 289 251 621 334 206 1285 19 161 2284 64 116 3034 290 250 629 335 205 1305 20 160 2305 65 115 3044 291 249 637 336 204 1326 21 159 2327 66 114 3053 292 248 645 337 203 1347 22 153 2348 67 113 3062 293 247 654 338 202 1368 23 157 2369 68 112 3071 294 246 663 339 201 1389 24 156 2390 69 111 3079 295 245 672 340 200 1411 25 155 2411 70 110 3087 296 244 682 341 199 1432 26 154 2431 71 109 3095 297 243 692 342 198 1454 27 153 2452 72 108 3102 293 242 703 343 197 1476 28 152 2472 73 107 3109 299 241 714 344 196 1498 29 151 2492 74 106 3115 300 240 726 345 195 1520 30 150 2512 75 105 3122 301 239 737 346 194 1542 31 149 2532 76 104 3128 302 238 749 347 193 1564 32 148 2551 77 103 3133 303 237 761 348 192 1586 33 147 25/0 78 102 3137 304 236 7/4 349 191 1608 34 146 2589 79 101 3142 305 235 787 350 190 1631 35 145 2608 80 100 3146 306 234 800 351 189 1653 36 144 2627 81 99 3150 307 233 814 352 188 16/6 37 143 2645 82 98 3153 308 232 828 353 187 1699 38 142 2663 83 97 3156 309 231 842 351 186 1721 39 141 2681 84 96 3159 310 230 856 355 185 1744 40 140 2699 85 95 3l6l 311 229 871 356 184 1767 41 139 2716 86 94 3163 312 228 886 357 18^ 1789 42 138 2733 87 93 3164 313 227 901 353 182 1812 43 137 2750 88 92 3165 314 226 917 359 181 1835 44 136 2767 89 91 3166 315 225 933 360 180 1858 45 135 2783 90 3166 Transits, fyc. of Jupiter s Satellites. 33 FOURTH SATELLITE. IIP. Numbers I and K. Arguments I + 2, K + 2. IV. Number ft Arg. Q of Jupiter. Divisor for Corr. ft'. Com. Arg. I K & ft' F 270 244 + 360 360 6 280 260 1 242' 1 10 350 21 10 350 6 290 250 236 1 20 340 42 20 340 7 300 240 227 3 30 1 330 62 30 330 7 310 230 215 5 40 320 79 40 320 8 320 220 200 7 50 310 94 50 310 10 330 210 183 10 60 300 107 60 300 13 340 200 164 13 70 290 116 70 290 21 350 IQO 143 17 80 280 121 80 280 ~67 180 122 20 90 270 123 90 270 + 56 10 170 101 23 100 260 121 100 260 19 20 160 80 27 110 250 116 110 250 11 30 150 61 30 120 240 107 120 240 8 40 140 44 33 130 230 94 130 230 6 50 130 29 35 140 220 79 140 220 5 '4 60 120 17 37 150 210 62 150 210 4*8 70 no 8 39 160 200 42 160 200 4 '5 80 100 2 39 170 190 21 170 190 4*3 90 40 180 180 180 180 + 4-2 NAUTICAL ALMANAC, 1835. APPENDIX. . (2nd Edition.) 34 New Talks for computing the Occultations, FOURTH SATELLITE. V. SEMIDURATION. Argument N. N Semidur. N Semidur. N Semidur. h m h m h m 1000 3000 '0 1340 2660 1 51 '2 1680 2320 2 20 '2 1010 2990 20 '9 1350 2650 1 52 '5 1690 2310 2 20 '7 1020 2980 29 '5 1360 2640 1 53 '7 1/00 2300 2 21 '2 1030 2970 36 '0 1370 2630 1 54 '9 1710 2290 2 21 '6 1040 2960 41 '4 1380 2620 1 56'1 1720 2280 2 22 '1 1050 2950 46-2 1390 2610 1 57'3 1730 22/0 2 22 '5 1060 2940 50 '5 1400 2600 1 58 '4 1740 2260 2 22*9 1070 2930 54'4 1410 2590 1 59-5 1750 2250 2 23 *3 1080 2920 58 '0 1420 2580 2 0*6 1760 2240 2 23 '7 1090 2910 1 1 '4 1430 2570 2 1-6 1770 2230 2 24*0 1100 2900 1 4-5 1440 2560 2 2'6 1780 2220 2 24'4 1110 2890 1 7'5 1450 2550 2 3 '6 1790 2210 2 24 '7 1120 2880 1 10-3 1460 2540 2 4 '6 1800 2200 2 25 '0 1130 2870 1 13 '0 1470 2530 2 5'5 1810 2190 2 25 '3 1140 2860 1 15'5 1480 2520 2 6'4 1820 2180 2 25 '6 1150 2850 1 18 '0 1490 2510 2 7'3 1830 2170 2 25'8 1160 2840 1 20'3 1500 2500 2 8 '2 1840 2160 2 26 ! 1170 2830 1 22 '5 1510 2490 2 9'0 . 1850 2150 2 26 '3 1180 2820 1 24 '7 1520 2480 2 9 '8 I860 2140 2 26 '5 1190 2810 1 26 '8 1530 2470 2 10'6 1870 2130 2 26-7 1200 2800 1 28 '8 1540 2460 2 11 '4 1880 2120 2 26 '9 1210 2790 1 30 '7 1550 2450 2 12-2 1890 2110 2 27'1 1220 2780 1 32-6 1560 2440 2 12 *9 1900 2100 2 27'3 1230 2770 1 34 '4 1570 2430 2 13-6 1910 2090 2 27-4 1240 2/60 1 36-2 1580 2420 2 14 '3 1920 2080 2 27-5 1250 2/50 1 37-9 1590 2410 2 15 '0 1930 2070 2 27-6 1260 2740 1 39'5 1600 2400 2 15'6 1940 2060 2 27-7- 1270 2730 1 41 -1 1610 2390 2 16 '3 1950 2050 2 27-8 1280 272Q 1 42 '7 1620 2380 2 16'9 I960 2040 2 27*9 "1290 2710 1 44 '2 1630 2370 2 17-5 1970 2030 2 27-9 1300 2700 1 45 '7 1640 2360 2 18 -1 1980 2020 2 28 '0 1310 2690 1 47-1 1650 2350 2 18 '6 1990 2010 2 28 '0 1320 2680 1 48 -5 1660 2340 2 19'2 2000 2000 2 28 -0 '1330 2670 1 49 '9 1670 2330 2 19'7 1340 2660 1 51 '2 1680 2320 2 20'2 For Satellite, use Geo. Long. For Shadow, use Hel. Long. or and Arg. N = Numb. (H + 1 + K + /6'+ ) and Arg. N := Numb. (H + 1 + K) Transits, fyc. of Jupiter s Satellites. 35 TABLES FOR FINDING THE CO-ORDINATES OF THE SATELLITES AT THE TIMES OF THEIR ECLIPSES, OR AT ANY TIME NEAR TO THE GEOCENTRIC CONJUNCTION. VI. CO-ORDINATES. FIRST SATELLITE. SECOND SATELLITE. Time from Divisor Time from Divisor Time from Divisor Conjunction. X for y. Conjunction. fory. Conjunction. fory. h m h m h m '00 14 00 0*00 14 2 10 1 *47 12 10 0'15 14 10 0'12 14 20 1 '58 12 20 0'29 14 20 0*23 14 30 1*69 11 30 0'44 13 30 '34 14 40 1 *80 11 40 0*58 13 40 045 14 50 1*92 11 50 0*78 12 50 0*57 13 30 2 '03 11 1 0'86 12 10 O'68 13 10 2*14 10 10 1 '00 12 10 0'80 13 20 2 '25 10 20 1 *14 11 20 0*91 13 30 2*36 10 30 1 *28 11 30 1'02 13 40 2*47 9 40 1 '42 10 40 1*13 12 50 2 '58 9 50 1 '55 9 50 1 '25 12 40 2 '69 9 2 1 '69 9 20 1 '36 12 10 2 '80 9 10 1 '82 8 10 1 *47 12 20 2 *90 8 20 1 '96 8 30 40 2 '09 2 '23 7 7 . N '700 N D '380 N THIRD SATELLITE. Time from Divisor Time from Divisor Time from Divisor Conjunction. for y. Conjunction. 9 for y. Conjunction. * fory. h m h m h m O'OO 14 2 40 1 '44 13 5 20 2 '86 11 10 o -09 14 50 1 '52 13 30 2 '94 11 20 0*18 14 3 1 '6l 13 40 3*03 11 30 0*27 14 10 1-70 13 50 3 '12 11 40 '36 14 20 1-79 13 6 3*21 11 50 0*45 14 30 1 '88 12 10 3 '30 10 1 "54 14 40 1-97 12 20 3*38 10 10 '63 14 50 2 '06 12 30 3-47 10 20 0-72 14 4 2 '15 12 40 3*56 10 30 0'81 13 10 2 '24 12 50 3-64 10 40 "90 13 20 2 '32 12 7 o 3-73 10 50 0*99 13 30 2 '41 12 10 3 '82 10 2 1 '08 13 40 2 '50 12 20 3'90 9 10 1-17 13 50 2'59 11 30 3-99 9 20 1-26 13 5 2'68 19 11 40 4 '08 9 30 1 '35 13 10 2-77 11 50 4-17 9 40 1'44 13 20 2*85 11 8 4 '25 9 XT i -ooo N y D C 3 36 New Tables for Computing the Occiiltations, VI. CO-ORDINATES. FOURTH SATELLITE. Time from Conjunction. X Divisor for y. Time from Conjunction. ,r Divisor fory. Time from Conjunction. X Divisor for y. h m h m h m 0*00 14 5 20 2'l6 13 10 40 4 '31 12 10 0*07 14 30 2'23 13 50 4-37 12 20 0'14 14 40 2-30 13 11 4.44 12 30 0'21 14 50 2'36 13 10 4 '51 12 40 0'28 14 6 2*43 13 20 4-57 11 50 0'35 14 10 2 '50 13 30 4 '64 11 1 0*41 14 20 2-56 13 40 4-71 11 10 *48 14 30 2 '63 13 50 4*77 11 20 0*55 14 40 2-70 13 12 4 '84 11 30 0'62 14 50 2-76 13 10 4-91 11 40 0'68 14 7 2-83 13 20 4-97 11 50 */5 14 10 2 '90 13 30 5 '04 11 2 0'81 14 20 2 '97 13 40 5 '10 11 10 0'88 14 30 3 '03 13 50 5-17 11 20 0'95 14 40 3'10 13 13 5 '23 11 30 1 '02 14 50 3-17 13 10 5 '30 11 40 1 '08 14 8 3 '24 12 20 5-37 11 50 1 '15 14 10 3'31 12 30 5 '43 11 3 1'22 14 20 3*37 12 40 5'50 1] 10 1 *29 14 30 3'44 12 50 5 '56 11 20 1 *36 14 40 3 '51 12 14 5'63 10 30 1 *42 13 50 3'57 12 10 5*70 10 40 1-49 13 9 3 '64 12 20 5'/6 10 50 1*56 13 10 3-71 12 30 . 5 '83 10 4 1-62 13 20 3-77 12 40 5'90 10 10 1-69 13 30 3 '83 12 50 5 *96 10 20 1.-76 13 40 3 '90 12 15 6 '0,3 10 30 1 -83 13 50 3-97 12 10 6 -10 10 40 1 *89 13 10 4 '04 12 20 6-16 10 50 1 '96 13 10 4 '11 12 30 6 '23 10 5 2 '03 13 20 4-17 12 40 6 -29 10 10 2 '10 13 30 4'24 12 50 6-36 10 20 2-16 13 40 4 '31 12 16 6*42 10 _ _ 2 *000 N D Transit!!, fyc. of Jupiter's Satellites. 37 VII. TABLES FOR CONFIGURATIONS. FIRST SATELLITE. SECOND SATELLITE. Time in Parts of a Mean Revolution. Time in Parts of a Mean Revolution. Hours. Parts. Min. Parts. Min. Parts. Hoars. Parts. Min. Parts. Min. Parts. 1 02354 1 00039 30 01177 1 01172 1 00020 30 00586 2 04708 2 073 31 1216 2 02345 2 039 31 606 3 0/063 3 118 32 1256 - 3 03517 3 059 32 625 4 09417 4 157 33 1295 4 04689 4 078 33 645 5 11771 5 196 34 1334 5 05862 5 098 34 664 6 14125 6 235 35 1373 6 07034 6 117 35 684 7 16480 7 275 36 1413 7 08206 7 137 36 703 8 18834 8 314 37 1452 8 09379 8 156 37 723 9 21188 9 353 38 1491 9 10551 9 176 38 742 10 23542 10 392 39 1530 10 11724 10 195 39 762 11 25897 11 432 40 1569 11 12896 11 215 40 782 12 28251 12 471 41 1609 12 14068 12 234 41 801 13 30605 13 510 42 1648 13 15241 13 254 42 821 14 32959 14 549 43 1687 14 16413 14 274 43 840 15 35314 15 589 44 1726 15 17585 15 293 44 860 16 37668 16 628 45 1766 16 18758 16 313 45 879 17 40022 17 667 46 1805 17 19930 17 332 46 899 18 42376 18 706 47 1844 18 21102 18 352 47 918 19 44731 19 746 48 1883 19 22275 19 371 48 938 20 '47085 20 785 49 1923 20 23447 20 391 49' 957 21 49439 21 824 50 1962 21 24619 21 410 50 977 22 51793 22 863 51 2001 22 25792 22 430 51 00996 23 54148 23 902 52 2040 23 26964 23 449 52 01016 24 56502 24 942 53 2080 24 28137 24 469 53 1036 25 oogsi 54 2119 25 488 54 1055 26 01020 55 2158 26 508 55 1075 27 1059 56 2197 27 527 56 1094 28 1099 57 2237 28 547 57 1114 29 1138 58 2276 29 567 58 1133 30 01177 59 2315 30 00586 59 1153 60 02354 60 01172 Multiples of Mean Revolutions. Multiples of Mean Revolutions. d h m d h m d h m d h m d h m d h m 1 18 28 '6 14 3 48 '8 26 13 9 "0 3 13 17 '9 17 18 29*5 31 23 41 '1 3 12 57'2 15 22 17*4 28 7 37 '6 7 2 35 '8 21 7 47 '4 35 12 59*0 5 7 25 '8 17 16 46-0 30 2 6 '2 10 15 53 '7 24 21 5'3 39' 2 16 '9 7 1 54*4 19 11 14 '6 31 20 34 '8 14 5 11 '6 28 10 23 '2 42 15 34 '7 8 20 23 '0 21 5 43 '2 33 15 3 '4 10 14 51 '6 23 11 '8 35 9 32 '0 12 9 20 *2 24 18 40 '4 37 4 0-6 38 New Tables Jbr computing the Occultations, VII. TABLES FOR CONFIGURATIONS. THIRD SATELLITE. FOURTH SATELLITE. Time in Parts of a Mean Revolution. Time in Parts of a Mean Revolution. Hours Parts. Min. Parts. Min. ! Parts. Hours. Parts. Min. Parts. Min. Parts. 1 00581 1 00010 30 00291 1 00249 1 00004 30 00124 2 01163 2 19 31 300 2 00497 2 08 31 128 3 01/44 3 29 32 310 3 00746 3 12 32 133 4 02326 4 39 33 320 4 00995 4 17 33 137 5 02907 5 48 34 329 5 01244 5 21 34 141 6 03489 6 58 35 339 6 01492 6 25 35 145 7 04070 7 68 36 349 7 01741 7 29 36 149 8 04651 8 78 37 359 8 01990 8 33 37 153 9 05233 9 87 38 368 9 02238 9 37 38 158 10 05814 10 00097 39 378 10 02487 10 41 39 162 11 06396 11 00107 40 388 11 02736 11 46 40 166 12 06977 12 116 41 397 12 02984 12 50 41 1/0 13 07558 13 126 42 407 13 03233 13 54 42 174 14 08140 14 136 43 417 14 03482 14 58 43 1/8 15 08721 15 145 2 750 750 760 740 78 ' 5 o- 65 -9 'I 45- ' 1 *3 -5 760 740 770 730 78 o -a 66-1 ' 2 45-8 4 -6 770 730 780 720 78 -8 66 -4 ' 3 46 * 3 o' 6^9 " 3 780 720 790 710 79*1 66-9 *6 47 -1 790 710 800 700 79-5 67-5 48 -0 8-6 1>7 800 700 *5 *7 2 *0 810 690 80-0 V 68-2 I 49-2 10-6 ; 810 690 *5 *Q 1 *4 2 *4 820 680 80-5 69-1 50-6 13-0 820 680 830 670 81-1 t 1 * 1 -5 52-1 is -7 2 ] 7 830 670 840 660 81-8 71 -1 l * 53-9 18 -8 840 660 850 650 82-6 * 8 72-3 }* 55-8 >' 22-2 3 ; 4 850 650 860 640 83-4 ; 8 73-6 2 -1 25-9 3 ' 860 640 870 6so 84 -3 ] 9 7 l'l > : ' 6 ' 2 l'-l 4 *0 2Q q 4-3 870 630 880 620 85 '2 62 -6 34-2 880 620 890 610 86-3 1 *6 65-2 ! 38-7 4 ' 5 890 610 900 600 1-0 1 -2 79-9 1<7 ' 1 -8 2 *7 2 *8 4 -8 5 *0 900 600 910 590 88 -5 81 >7 1- 7 : 7 3-0 48 ' 5 5- 910 590 920 580 89 -6 83-5 | 1 53-7 920 580 i -q 3 *0 5 *3 930 570 940 560 950 550 90-8 - 92-1 93-3 I* 85-4 %* i: 89-4 76-7 ' ' O O 79-9 ' 3-2 83-1 ;: ' ; ; 930 570 940 560 950 550 960 540 94 - 6 ! 91 * 5 ' 86 -4 5 '8 76-1 960 540 970 530 96-o : 93-6 2<1 2 -1 89 * 8 3*4 5 -q 82 -0 970 530 980 520 97-4 J , 95-7 93-2 87 * 9 6-1 980 520 f 12 2 *2 3 *4 990 510 9316 ! 97>9 2-1 96 " 6 3-4 94 o 6 990 510 000 500 100 -0 100-0 100-0 100-0 , 000 500 1 *4 2 i 3 *4 6 010 490 101-4 102-1 103-4 106 -o , " 010 490 1 *2 2 *2 3 -4 6 -1 020 480 102 -6 104 -3 / 106-8 112-1 020 480 030 470 104-0 * [ 4 106-4 110-2 ' 5 -9 118-0 030 470 040 460 105-4 2 1 108 -5 113 -6 ; 123 -g 5< 9 040 460 050 450 106-7 no-6 116-9 ; 129-7 050 450 1 *2 2 '0 3 *2 5 *7 060 440 107-9 112-6 120-1 135-4 060 440 1 *3 2 -0 3 *2 5 *6 070 430 109-2 114*6 123-3 141-0 , 070 430 080 420 1 *3 110*4 116-5 1<9 126-3 3 ' 5 -3 146-3 080 420 1 *1 1 *8 3 -0 5 -2 090 410 111-5 1-3 H8-3 129 ' 3 2-8 151-5 5 *0 090 410 100 400 112-7 120-1 132-1 156-5 100 400 1 *0 1 *7 2 7 4 *8 110 390 113 * 7 . 121 * 8 .6 134-8 ' 161 * 3 rl no 390 120 380 114-8 123-4 \ 6 .2 o 137-4 165-8 ' 120 380 130 370 115 ' 7 0-' 124-9 " 9 - r: 4 *3 130 370 140 360 116-6 126-4 \ 5 142-1 174 -1 140 360 *8 ! 3 *7 150 350 117-4 . 127 '7 144-2 ^ 177-8 g. 7 150 350 160 340 118-2 ' 8 128 -9 146 -1 181-2 160 340 170 330 118 ' 9 0-6 129 * 9 !'o 147-9 ;:: 184-3 ' 170 330 180 320 119-5 * 130-9 149-4 *w y 180 320 190 310 120-0 o -q 131-8 189-4 ' 190 310 n *7 1 *2 2 200 300 120-5 132-5 152-0 191 * 4 1-7 200 300 *4 '6 o -q 210 290 220 280 120 >9 0-3 121-2 133-1 133-6 ' 5 152 ' 9 0-8 153-7 194-4 210 290 220 280 *2 *3 *5 i -o 230 270 121 -4 133-9 Q . 2 154-2 Qt3 195 ' 4 0-5 230 270 240 260 121-5 [ l 134 -1 154 -5 U i) 195-9 240 260 250 250 121 -6 134-2 154-6 196-1 250 250 40 ON THE COMPUTATION OF AN EPHEMERIS OF A COMET FROM ITS ELEMENTS. BY Mr. W. S. B. WOOLHOUSE. IN computing the places of a comet from its elements, every operation admits of a strict and direct method, except the formation of the anomalies ; but in this, as in most other calculations, we can have recourse to facilities in the management of a series which are'not attainable in working an independent case. It is here intended to give such formulae as may be best suited to the purposes of actual computation. Let m denote the mean daily motion of the comet, e the excentricity of its orbit, u its excentric anomaly from the perihelion, and t the number of days from the peri- helion passage ; and, by the elliptic theory, u e sin u mt ( 1 ) which is the equation from which u is to be deduced from the known value of the mean anomaly mt. Differentiate with respect to t, and ( 1 e cos u} = m at Let r be the radius vector which corresponds with u, and a the major semi-axis of the elliptic orbit, so that r = a (1 e cos u), and we shall thus have du fa dt \rj which expresses the motion of u when the comet is at the point in the orbit whose radius vector is r. Let n be the number of days which intervene between the succes- sive places of the comet ; and suppose we already know the present values of u, r, and also iz.u r_ 15 the preceding values, which correspond with t n days from the peri- helion ; and let it be required to find the next value u lt which answers to t + n days from the perihelion. Now expresses the motion of u near to the middle time between t n and t, or near to the time t days ; and similarly expresses the motion near to the mean of the times t and t + n. Hence u u_, du are logarithms of motions of u at three times, very nearly in arithmetical progression, and are themselves nearly in arithmetical progression, because the equation . du i* ' g ~di ~ g ~~ g T shows that the logarithms of the motions of u at different times will difference the same as log r, only with different signs, and log r is a quantity which, at equal inter- vals, has a small second difference compared with the first. If we therefore assume the above logarithms to be in arithmetical progression, we get On the Computation of an Ephemens of a Comet. 41 /. log (M! u) = 2 log -- |-2 log (m/z) log (w w_j) Or, without logarithms, To compute a series of excentric anomalies by means of this formula we must obviously know previously two values to begin with ; and to effect this we may com- mence close to the perihelion. If /> = a(l e), the perihelion distance, we shall have at this point du a m w == 7 m = ......... < 3) which motion may be taken as uniform very near to the perihelion. When the value of u v is found as above, let the corresponding mean anomaly be com- puted from the expression u e sin w, and let (wO be the error of the result, and the error of u v will be But as before we have nearly and hence which, along with (2), is a convenient form for the computation of the correction to be applied to u i9 and will mostly produce a result sufficiently accurate, as will be corroborated by again trying this last value of u in the equation (1). We ought here to observe, that in finding the value of the term e sin u, it must be reduced to seconds of arc by dividing by sin l". Thus, if a constant c be formed Q ~ - j n we shall have log c + log sin u for the logarithm of the arc in seconds which is to be deducted from u ; and this arc can be read off with the greatest facility from the logarithms of Callet. For the radius vector we have r = a ( 1 e cos w) = a {1 e (cos 2 w sinHw)} t= a {cos 2 ^w + sinHw e (cosHw sin 2 ^w)} = a {(1 e) cos 8 *tt +(!+// + w) sin C x r sin a sin (A + 0) y =2 r sin b sin (B + 0) z := r sin c sin (C + 0) The constants A, B, C, sin a, sin b, sin c, will perhaps be more readily found by the following formulae, as the computer will have less consideration in the determination of the particular quadrants in which the angles A, B, C, will fall. tan i sin i tan = cos sn sin a cos A = sin SI cos i sin a sin A =: cos SI sin b cosB=^ cos (+w) I sin c cosC=s sin sin b sin B =sin $2 cos w sin c sin C= sin SI sin w (8) The arc "^ is to be taken out in the first quadrant with its proper sign ; and sin a., sin 6, sin c, being always positive, by attending to the algebraic signs we shall deduce those of both the cosine and the sine of the angles A, B, C. It will not be necessary to take out the arcs a, b, c, as their log. sines only are wanted. On the Computation of an Ephemeris of a Comet. 43 We may also avoid the computation of the successive values of Q by taking A' = A +(*-) B' = B + Or-) C'=rC+Or-)...(9) for then x = r sin a sin (A' -f v) \ y = r sin b sin (B' + 1;) I (10) z r sin c sin (C' + v) } In these computations we may use the descending node %S instead of the ascending ; and the algebraic sign of the inclination i must be taken thus : 1 . If the ascending node & is used when the motion is { jgj^ } < with the { { } sign . when the motion is { 2. If the descending node 33 is used - with the { ^ } sign. Let us now assume the centre of the Earth for the origin of co-ordinates, and denote those of the Sun by X, Y, Z ; then if denote the sun's longitude, and R its radius vector or distance from the earth, we shall have X R cos Y = R sin cos w Z = R sin sin w = Y tan 6 cos w tan z =: sn sin sin ^ cos = sin & sin i q' = 5 cos =: j sn tan A = sin a =i . sin 6 = -7 tan C = , smB . sm A a- s: r sin a sin (A' + v) y 2= r sin 6 sin (B'+ v) X = R cos Y == R sin cos w Y +y Z +z tan a -^ * tan $ = ^ cos sm c = P f/ sinC X + or i= r sin c sin (C r + v) Z = Y tan o> sin^ EXAMPLE. The Elements of Halley's Comet for its perihelion passage in the year 1835 are, as deduced by Pontecoulant in the Connais. des Terns for 1832, p. 33, Perihelion passage, Nov. 7 d ' 2 5 mean Paris time. Semi-axis major ... a .... 17 '9&705 Excentricity e '9675212 Perihelion on orbit ir 304 31' 43" Ascending node ...&.... 55 30 Inclination i .... 17 44 24 Motion RETROGRADE. 3 -55002 is the logarithm of the sun's mean daily motion, On the Computation of an Ephemeris of a Comet. 45 To compute the places of this comet at intervals of 4 days, we have n = 4, and we proceed as follows : log a ............. 1 -25496 log a ............. 1 -25496 iloga ............. 0-62748 log(l e) G'032479 8'51l6() 1-88244 log /i 2 ............. 976656 Const ............. 3 -55002 log h ............. 9 '88328 logm ............. 1-66758 log(l+602 6 log (mri) .......... 2 -26964 log k ............. '77444 log 6? ............. 9 '9856605 log sin 1" ......... 4-6855749 c ................ 5-3000856 Perihelion passage Nov. 7 d '2000 mean Paris time 0065 Diff. long. 7-1935 mean Greenwich time. Thus, as we compute for mean noon at Greenwich, we have On Nov. 7, time preceding perihelion = + O d '1935 log -1935 ____ 9 -28668 log m ......... 1 '66758 .*. Nov. 7, mt = + 0' 9" -00. ... 0-95426 The comet's motion being retrograde, we thence deduce, as under, the mean ano- malies for the following days, by the successive subtraction of the value of (wn), which is the mean motion of the comet in four days (mt} 1835, Nov. 7 ---- +0 9'00 11 ____ 2 57 '05 15 ____ 6 3-10 &c. &c. With these we now begin the calculation of the Anomalies and Radii Vectores. Nov. 7, mt = + 0' 9" '00 ..................... -95426 (1 e?) ........... 8-51160 u = 4' 37" ...................... 2 -44266 c ................ 5-3000856 sin u ............. 7 -1280545 c sin u . .0 4 28 '00 . , 2 '4281401 9 -00 u = V 18"' 5 mt ............... 9 '00 * sin $ u ........... 6 -82702 cos u .......... '00000 siniw ...... > ..... ^7^60146 hcoB^u .......... 9 '88328 ............ 9-88328 tan ............... 7 71818 cos * v .......... 9 '99999 bv tl 18'-0 *logr ............ 9 '88329 46 On the Computation of an Ephemeris of a Comet. v = +0 36'-o Nov. 7- log r == 9 '76658 a 1 -25496 1 '48838 Nov. 11, mt = 2 ; 57" '05 2-24810 (1 ) ,.,,,., 8 '51l6 r m t\ . . . . *6l 9 '7853 Corr. u . . . .... 19 1 '2737 u . , . . . =1 30' 32" .... sin ... 8'4204844 c sin w ... 1 27 34-97 3 -7205700 mt 3 57 -03 u 2 57 -05 = 45' 16" sin \ u . . . , * .... 8*11949 cos ^ u ....... Q '00006 k sin ^ u . . . . . ... 8*89393 h cos \ u.. , . . . . 9 '88324 h cos % u . . . . .... 9*88324 (tan .... 9 *0 1 069 cos ^ v o -00773 9*88551 .... 1 1 42-2 log ? 9 "77102 Nov. 11. a 1 -25496 a 1 '48394 r u = 1 II \ T / . . . . . 1 30 32 (mny 2 -96788 4 -53928 t j =: . . . . , ..... + 4 37 7 -50716 u u ! . . . 1 35 9 ..... log .. 3 75656 u, u ~ 1 33 51 ,, 3 -75060 * 7/ 3 4 23 c .. 5 '3000856 sin Ui 8 72923Q5 c sin Wj , , , . . 2 58 18 '55 4 -0293251 6 4 -45 1 -488 r= mt V... i-480 On the Computation of an Ephemeris of a Comet. 47 [ ] 1 '480 J (roO I -35. . \rj ' r,., "130 Corr. w t 41 . . .. 3 3 42 1 -610 . sin 8 -7276286 1 2 57 38'94 4'0277142 mt . 6 3 -06 6 3 -10 %u == 1 31' 51" sin u 8 -42675 sinw 9'20119 hcos$u 9 '88312 Jtan 9 -31807 \i v 7T~~45''0 v = . , . 23 30 -0 &C. cos u 9 '99984 h cos & u 9 '88312 cos v t , 9 '99080 log r 9 -89232 log r = 9 78464 -a 1 -25496 Nov. 15. The remaining anomalies to the end of the intended Ephemeris may now be de- termined in exactly the same manner as this for Nov. 15. The computation of the co-ordinate constants comes next, and will be as follows : 97531280 fsin + 9-9159937 Jf \cos i + 9 '9788417 tanz... . 9 -5050280 tan 9 7519000 V 29 27' 29" w 23 27 40 q 9 '8948354 ftan 9 '8582926 A. 144 11' Isin + 9 -7672704 sin a 9'9858576 ir ^.. 249 1 43 A'.. 33 12 53 sin &... + 9*9159937 cosw ____ + 9 '9625258 + 9'9159937 sinw. .. . + 9 "6000211 p f + 9*8785195 p" + 9*5160148 sin i .... 9 -4838697 Here i is negative, see p. 43 sin T/T . . . 9 -6917764 + 9 7920933 + 9 7920933 5 59 49 cos + 9-9976168 ... + 9 7897HH . + -0888094 50 49' 4" .sin + 9 -8893805 sin &.... 9'9891390 sin 9 -0190141 q" 8 -8111074 Stan -7049074 C 101 9 r 37 7 ' sin + 9-9917087 sine.. 9*5243061 249 43 299 50 47 249 1 43 350 11 20 48 On the Computation of an Ephemeris of a Comet. Hence we have for the heliocentric co-ordinates of the comet, logo; = log sin ( 33 12 '9 + u) + 9*98586 + log r logy == log sin (299 50 '8 + v) + 9*98914 + log r log z = log sin (350 11 3 + r) + 9 '52431 + log r We shall take Nov. 15 for the completion of an example in which X, Y, Z, are taken from Weisse's tables. November 15. A' / 33 12 '9 B' / 299 50 '8 C' / 350 11 '3 23 30-0 v 23 30 -0 11 23 30 -0 A!+v. , 9 42 '9 (B' + i?. . 276 20 -8 fC'-ffr.; 326 41 '3 I sin . * j* 9 -22724 [sin 9 "99733 )sin 9 '73972 9 '98586 #w .* 9 '78464 r 9 "98914 9 78464 r 9 -52431 9 '78464 log . , ;v / 8 -99774 flog . . 9 '77111 n Q0 . 9 '04867 1 5 I o T . 4. o "09948 iy. . .... o -59035 j z -11186 X . . . . . . . -60254 71888 z... 0-31194 X4-x -50306 Y+v . . - 1 -30923 Z 4-2 '42380 ~1~ log (Y+y) log (X + tf) 9 -70162 . log (Z + ) 9-62716 9 -70162 a . = 248 58' '9 tan ot + -41539) 9 -92554 sin oc 9 -97010} COS Ot 9 -55471 = l6 h 35 ra '9 f 3 16 48' -8 . tan S 9 -48025 \ same sij n as Z-f-z Log. cos sin dist. from 5 9 '98103 J 9 -46128 , 0-16588 When comes out near 90 or 270 its sine is taken out, as in this example, for the purpose of getting the cosine more accurately, by subtracting the tangent from the sine; but when is nearer to or 180 it will be better not to regard the sine, as the cosine itself can then be taken more accurately from the tables. 49 COMPARISON OF RESULTS DEDUCED FROM M. BURCKHARDT'S AND M. DAMOISEAU'S LUNAR TABLES. PROFESSOR SCHUMACHER has given, in his Ephemeris of the Distances of the four planets, Venus, Mars, Jupiter, and Saturn, for the year 1834, (Copenhagen, 1832.) an Ephemeris of the Moon for every third hour of mean time at Greenwich, founded upon DAMOISEAU'S Lunar Tables ; and the following Table contains the differences between his results and those in the Nautical Almanac for 1834, which have been derived from BURCKHARDT'S Tables. The Differences of Right Ascensions and Declinations are for the Mean Noon of each day, and those of the Horizontal Parallaxes for Mean Midnight. Denoting Professor SCHUMACHER'S results by D, and those in the Nautical Almanac by B; the numbers in the Table represent, in all cases, D B, or the quantity to be added to the Nautical Almanac results (South Declinations being considered ) to produce those of Professor SCHUMACHER, According to BURCKHARDT, C 's Sern. 's Hor. Par. = 0-2)25 (BURCKHARDT'S Tables dc la Lune, p. 73. Paris, 1812.) According to DAMOISEAU, -~ = 0-27263 (SCHUMACHER'S Ephemeris for 1834, p. 134,) < s Hor. Par. NAUTICAL ALMANAC, 1835, Ari'ENuix. (2nd Edition.) 50 Comparison of Burekhardt's TABLE, Showing the Difference between the results, for the year 1834, derived from BURCKHARDT'S and DAMOISEAU'S LUNAR TABLES. fr JANUARY. FEBRUARY. MARCH. APRIL. ffi O r R. A. Dec. H. P. R. A. Dec. H.P. R. A. Dec. H.P. R. A. Dec. H.P. // n n n n // ;/ n II // // n i -13-6+ 97 + 2-0 -13-7 + 9'3 + 2-1 6-9+4-6+3-8 3-0 0-8 + 1'9 2 14'5 10*1 11*8 13'0 8-1 ro 7'3 4-0 3-1 - 0'2 1'4 T4 3 15-3 10'8 + 2'0 lO'l 6'5 0'9 6-3 3-0 2*3 + 3-4 1-2 + 0'4 4 14'8 10'3 rs 3'2 4-8+07 3-0 2-3 T3 7-0 1-3 o-i 5 1T5 8*8 1-6 + 4*2 3-60-1 + 2'9 1-5 0'8 10'3 0-8 0-6 6 6-3 5'8 1-5 lO'O 2-9 0-2 9'0 1'9 +0-1 13-3 0'3 0'9 7 0'5 3*3 rs 12'5 3-0 0-5 13'6 2'5 0-4 14-5 +0-6 0-7 8 + 4'0 2'1 0'8 12'0 1*9 3 15-5 2-5 T2 13'4 +0'8 0-3 9 5'8 + 0'9 + 0'3 9'0 + 0'2 '3 15'4 1'5 0-9 9'8 O'O O'O 10 4'2 - 0-6 O'l 6'5 -1-7 4 13'5 + 0-8 1-4 + 3-7 -1-7 + 0'5 11 2'0 2'3 0'5 4'1 3-1 6 10'7 0-3 ri - l'9 2'8 0'8 12 + 0'2 4'7 T2 2'7 4-0 3 6-5 2-1 0-9 6-0 2'8 0-7 13 O'l 6-5 ro rs 4'3 T4 + 2-4 3-1 0-4 6-5 r6 + 0-4 14 + 0'3 7-6 I'l + 1-1 3'5 2-6 T4 3-5 0'5 3-8 0-3 0'3 15 1'8 7-2 ri 1'2 3-7 2'2 3-0 2'9 0'9 2-2 + 0'2 1-2 16 4'2 6'8 1-5 4-7 3-9 2'4 2'9 I'l 1'9 3-2 0'5 1-4 17 3'5 6-1 rs 10'2 4-2 2-3 3-8 0-7 2'4 7-0 1-4 1'9 18 + T2 6-2 2-3 15-7 2'8 2'5 8'1 -0-6 2'8 10-3 2'9 2'3 19 - 2'7 6-3 2'2 18'9 -0-6 1-3 14-1 + 0*4 2'7 9'8 3-6 1*9 20 6-3 5'8 2'0 18-5+1-8 0-4 19'6 2-0 2*3 6-5 3-6 T4 21 8-3 4-0 0'8 14'5 4'1 + 1-2 19'6 5-1 T4 3-9 2-9 -0-6 22 9'3 rs + 0'3 lO'l 5-8 2-6 12-7 6-0 O'l 3-2 2'8 + 0-3 23 lO'l + 0'3 ro 7'0 6-6 3-7 5'0 4'7 + 1-3 6-4 3*4 1-4 24 ir6 2'8 2'3 8'2 7-4 4'6 2-1 4'3 2-3 lO'O 4'2 2-0 25 14-0 5'3 2-9 iro 9'4 5'2 3'8 5-2 3'4 14-4 4-2 2'3 26 16'0 8'2 3'2 12'3 9'2 5'4 7'8 5'9 4-1 15-9 2'5 2'4 27 15'9 10'3 3'8 10'8 8-0 5-3 n-6 6-4 4-4 14-2 + 0-1 1-6 28 15-4 11-2 3'9 8'3 +6-1 + 5-0 12'2 5-3 4-4 9'9 2-0 1'7 29 13-8 10-3 3'8 10-5 3'3 4-3 6-8 3'3 T3 30 12*1 9'3 3'8 _ _ _ _ _ 8'2 I'l 3'1 4-6 -4-2 + 1-0 31 12'9 + 9*4 + 2'9 - 4-9 +0-6 + 2'7 ~ ~ _ _ ' and Damoweaus Lunar Tables. 51 TABLE, Showing the Difference between the results, for the year 1834, derived from BURCKHARDT'S and DAMOISEAU'S LUNAR TABLES. 1 . MAY. JUNE. JULY. AUGUST. n O Q R.A. Dec. H.P. R.A. Dec. H.P. R. A. Dec. H.P. R. A. Dec. H.P. H n /; n it * H n n 1 3'1 -4'7 + 0'4 +0-6 -6-1 ri + 3'0 4-1 O'S + 1*7 2-il+rs 2 ro 5'3 0'3 4'3 3-7 1'3 2-8 3*1 0'2 + 1*7 1-9 1-6 3 + 2-6 4'6 0-6 7-2 1'4 ro 3'1 -1'5 + 0'3 1-4 1-2 1-4 4 -h 6'3 2'8 0-7 7'7 + 0'5 O'O 3'4 + 0-5 0-6 8-7 + % 8 + ro 5 -10-4 0'2 ro 6-4 1-8 +0-6 + 1'8 I'l 1-1 14-4 3*7 0-3 6 12'5 ~t"" 1 <5 0-8 + 3'5 2'8 0-9 rs 2'6 1'2 17-3 6-4 0-5 7 H'3 1'5 O'O O'O 3'7 1-7 6-7 rs O'S 18'2 7-3 0-9 8 6'6 1'3 + 0-6 3'3 4'8 l;6 9*2 5'8 0*7 16'6 67 0'9 9 + 0'6 0-7 1'3 6-1 6-0 r6 10'4 7-5 ro 12-8 4'6 O'S 10 5'0 0-7 1-7 7'7 7-4 2'1 9'7 8'2 1-2 8-3 2-4 0'2 n 7'7 1'3 1-7 7-1 8-3 1-6 7;s 7'7 i'7 3-5 + 0*1 O'S 12 8'8 2'9 rs 5'0 8'2 2'3 6-4 1-7 + O'S 0'6 0'3 13 7'5 3'6 1-6 2'2 7'i rs 1'9 4'5 rs 3'0 0*9 0*4 14 4'5 3'8 0'8 + 0'7 5-4 i'7 + rs 3'5 ri 5'5 G'4+0'2 15 2'4 3'4 + 0'3 2-7 4'4 +0-7 3'2 3-1 0-6 5'9 0-1 0-4 16 0-8 2'9 0*2 + 2'0 4'5 -O'l 2-7 3'5 0'4 6'2 + 0'2 0*8 17 1'2 2'8 ri 0'2 5*7 0-9 + 0-6 4'4 O'l 4'0 O'S ro 18 r6 3'0 1'3 2'6 6'2 0-7 0'3 4'6 0'4 + O'S 2'5 111 19 2'5 4'0 1-7 4'3 6'0 0'4 t-6 3-7 0-9 - 2'9 4-5 0'3 20 3'6 4'2 1'4 4'4 4'9 O'l 3'1 + 1'6 + 0'8 4-7 6-3 +0-1 21 5'4 4'0 0'8 4'1 3-3 + 0'3 3'4 -0'9 O'l 4'2 7-0 -0-7 22 7'4 3'8 O'O 4'4 + 1-4 O'l 3'2 2'4 O'S 2'0 6-2 0'8 23 9'0 2'9 +0'4 3'7 1 ' ^ JL t 0'8 2*7 4-4 1'3 + 0-7 4-2 0-3 24 10'3 + ro 0-6 l'9 2'Q ** \s 1-3 1-7 5'3 2-1 2'2 3-6 O'O 25 10'3 -0-9 + 0'4 l'9 4'9 7 O'l S'l 1'7 2-3 2-9 + 0'5 26 8'0 2-7 O'l 2'7 6'2 '8 + 2-7 4'4 1'4 + 0'4 2'9 rs 27 5'5 4'3 0'5 2'4 7-1 6 3-7 3'9 O'S - i'7 2-7 2'1 28 4'9 5'9 0'4 0'8 7'4 5 3-4 4'0 O'O 2'9 2'4 2'9 29 5'1 7-5 0-4 + 0'8 6-4 1 rs 4'4 + 0'8 2'2 1 9 3'! 30 5'3 11 + T8 5 '4 0'5 0'2 42 0-7 1-6 1*9 3-5 31 - 3'1 8'1 0-8 + O'S 3'4 + 1-1 2*3 T4 + 3'3 52 Comparison of Bttrck/iardt's, &;c. TABLE, Showing the Difference between the results, for the year 1834, derived from BURCKHARDT'S and DAMOISEAU'S LUNAR TABLES. 1 SEPTEMBER. OCTOBER. NOVEMBER. DECEMBER. &* R. A. Dec. H.P. R.A. Dec. H.P. R. A. Dec. H.P. R. A. Dec. H.P. tt n n H ;/ it it n n I - 6-0 + 0"! 10-2 + 5'5 + 2'8 10*9 +6-6 + 1-2 -2-9+1-4 O'O 2 12'3 2'9 1'2 16'3 9'4 + 1'2 12'0 5'6 0'3 7-0+0-3 ; I'O 3 19'3 7-2 +0-1 21-2 in O'O 9'9 3'2 ro 7'8 rs 1-7 4 23'3 9.5 -0-9 19-5 9-0 ro 4'3 + 0-7 2'3 3'9 3'6 2'2 5 22'0 8'9 T5 12-3 4'4 1-8 + 0'3 0'5 3'0 + 0-6 4-3 26 6 17-5 57 2'4 - 3-7+ 0-7 3-1 4'2 1-4 3'9 4-2 4'3 2'4 7 9'9 + T4 2'4 + 2'2 ro 3'4 72 rs 3'5 5-1 4-8 2'2 8 3'4 -r6 2'7 5'0 1'4 4'0 8'0 2'4 3-3 5'4 5'1 r6 9 + o-i 2'8 2'4 4-6 1-5 4'0 7'7 2-6 3'0 5'9 4-6 rs 10 T5 2;9 2'5 5'5 2'0 3*7 8'5 2'7 2'2 6-6 5'0 0-9 11 4'2 2'3 8'1 2'0 2"8 8'6 2'4 1-5 6'5 3-7 12 6'9 2'0 T2 9'6 1-7 2'0 8'9 rs ri 4-6 3-1 0-3 13 9'8 2'1 0'4 lO'O 1-8 ro 6'9 rs -0-6 2-6 2'3 + 0-2 14 lO'l ]'9 O'O 8'8 2'3 0-6 + 3"8 rs 00 + 1'4 ro ri 15 7*9 3'4 + 0-5 5'9 3'2 0'5 O'O 1*6 -fO'l 0-3 + 0-2 16 16 + 3'7 4'7 0*4 + 2*3 4-3 + 0'1 - 2-6 -0-7 0'4 2'2 1'7 2'0 17 0'5 6*7 0'4 0'7 4'7 O'l 4-o+ri 0'5 3'0 3-6 1'9 18 2'7 7'9 0'5 3-1 3'8 O'O 2'5 3-1 0'6 2-3 4-7 1'2 19 3-1 7-1 0'3 3'9 2-7 + 0-4 ro 4'7 0-8 1-2 5-1 1-4 20 2'7 5-5 0'2 1-2 0-6 + 1-2 4'8 0-6 + 0'1 4*9 0'5 21 T5 3'9 0'3 3-3 + 0'2 0'8 + 0-6 4'8 0'8 -ro 5'2 0'5 22 T4 3'0 0'8 1-9 1'9 1-2 1'5 5'3 r6 3-9 5*9 0'9 23 1*3 T6 r6 1-7 2'4 1*9 4-6 5'8 2-7 6-6 6-7 1-6 24 2'2 0'8 2-3 4*4 3'0 3'0 6-6 6'7 3'2 7*4 6-7 rs 25 4'0 0-5 3-0 8'7 3'9 3'8 5-7 6'3 4'0 5'8 5'4 0-7 26 6-1 +0-1 3'8 10'5 4'8 5-0 1'8 3'8 3-7 1'9 3'2 27 77 0'5 4'7 8'6 5'3 5'3 + 2-1 1-8 3'0 + 2'5 1'9 O'l 28 7'9 T4 4'8 4-9 4-6 5-0 4'8 0'8 2'3 6-0 ri 0-6 29 6-5 2'5 4'8 T8 3*1 4'2 4'6 0'4 1-7 5'5 1'5 0-6 30 - 6-3 + 3'4 + 3'8 T8 3'4 3'4 + o-8+ri + ri 3-7 + 0'9 n 31 - 6-1 + 5'6 + l'9 +0-1 -0-4 1*4 1 53 ON ECLIPSES. BY MR. W. S. B. WOOLHOUSE. HEAD ASSISTANT ON THE NAUTICAL ALMANAC ESTABLISHMENT. ECLIPSES, in all the varieties of aspect which they present to different places on the Earth, form an entertaining subject for discussion; and, without considering the public interest generally excited by their prediction and appearance, the use of them, as a test of the degree of perfection of the lunar and solar tables, and in the determina- tion and corroboration of geographical positions, &c., renders their accurate calculation an object of some importance. The popularity of the phenomena naturally called the attention of astronomers, at an early period, into the field of investigation, and several methods of calculation have been adopted by different authors at various periods. . For the general circumstances which take place on the Earth, the plan of ortho- graphic projection, though it can only be recognised as affording good approximations, seems to have predominated, and to have been almost exclusively adopted in actual calculations. This method is explained in the Astronomical treatises of De La Lande and Delambre, and more recently by Hallaschka, in his Elementa Edipsium, (Pragse, 1816), where an example is to be found at length. Various particulars are laid down in a more accurate manner in Memoires sur l y Astronomic Pratique. Par M. J. Monteiro Da Rocha, traduits du Portugais (Paris, 1808). The circumstances of an Eclipse for a particular place are usually calculated by the "Method of the Nonagesimal," which refers the bodies to the Ecliptic, and an example of which may be seen in the work of Hallaschka above mentioned. This part of the subject has also been discussed analytically by Lagrange, in the Astron. Jahrbuch for 1782; and Professor Bessel has since made some important additions to the theory, in a paper inserted in the Astronomische Nachrichten, vol. vii., No. 151, which is to be found translated in the Philosophical Magazine, vol. viii. As the numerous calculations which may be required for an eclipse, such as of the Maps, &c. given in the Nautical Almanac, could not be performed without many perplexing references to different authors, it has been presumed that a complete and systematic set of formulae would be generally acceptable ; and such a conviction has led to the drawing up of the following paper, which contains an extensive classification of useful remarks and formulae, developed and arranged with a careful view to their practical application, and with the endeavour to establish a direct and uniform mode of conducting each species of calculation. NAUTICAL ALMANAC, 1836. APPENDIX. e 54 On Eclipses. LIMITS WHICH DETERMINE THE OCCURRENCES OF ECLIPSES. ELEMENTS. The following elements, used in the calculation of the limits, have been derived from the Tables of Damoiseau, Burckhardt, and Carlini, viz.: Moon's Horizontal Parallax - - - (greatest 6l 32 1 least 52 50 Sun's Horizontal Parallax - - - j f eatest 9 1 least 8 Moon's Semidiameter ----- \ I least 14 24 .,. [ greatest 16 18 Sun s Semidiameter ------ { I least 15 45 ,, , TT , ,. . T v , f greatest 38 35 Moon's Hourly motion in Longitude - < I least 27 47 Sun's Hourly motion in Longitude - ! f I least 2 23 Moon's Hourly motion in Latitude - < , ' J I least " Inclination of Moon's Orbit with Ecliptic ! f^ I least 4 57 22 LIMITS. For the occurrence of an eclipse of the Moon : 1. The greatest possible distance of the centres of the Moon and Earth's Shadow at the time of contact, is 63' 29". 2. At the time of true ecliptic conjunction of the Moon and Earth's Shadow, or at the time of opposition or Full Moon, the greatest possible latitude of the Moon is 63' 45". 3. At the time of opposition, or Full Moon, the greatest possible distance of the centre of the Moon or of the Earth's Shadow from the ascending or descending node of the Moon's orbit is 12 24'. For the occurrence of an eclipse of the Sun : 1. The greatest possible distance of the centres of the Sun and Moon, at the time of contact, is 1 34' 28". 2. At the time of true conjunction of the Sun and Moon, the greatest possible latitude of the Moon is 1 34' 52". 3. At the time of true conjunction of the Sun and Moon, or the time of New Moon, the greatest possible distance of the centre of the Sun or Moon from one of the nodes of the Moon's orbit is 18 36'. The third of these limits applies to the true place of the node, which may differ considerably from the mean place. The most convenient and certain limits, however, will be those of the Moon's latitude (), and will be as follows: On Eclipses. 55 1. At the time of Full Moon an eclipse of the MOON will be certain 1 , f < 51' 57" impossible i when ^{> 63 45 and doubtful between these limits. For the doubtful cases, an eclipse will result when in which P, s, denote the equatorial horizontal parallax and semidiameter of the Moon, and it, l 34 52 and doubtful between these limits. For the doubtful cases, an eclipse will happen when PARALLAX. If a straight line be drawn from the centre of the Earth to any assumed place, It will be the radius of the Earth for that place, and this radius we shall designate by the letter p. This radius />, produced upwards towards the heavens, will determine what we shall call the central zenith, being that point which spherically determines our true position in relation to the centre of the Earth. The apparent zenith, however, is naturally determined by a line which is vertical to the observer, and therefoie a normal to the spheroidal surface of the Earth. The small angular deviation of this normal from the radius of the Earth, or the angular distance between the central and ap- parent zeniths, is what astronomers call >S : V (l+ 7 tan'0 == V0-' 2 ^*0 1 cos I' " where e = ^/(l 7 2 ) is the excentricity of the meridian. Also 42 ' The equations (1), (2) are convenient, and the latter may be simply resolved by logarithms, thus : p = COS ^ From (1) may also be deduced tan x 7 tan /' = = ^/ (tan / tan /') /_, } (7) tan (/'-/) ^_ l- s in2x Here we may remark, that in reducing the geographical latitude to the geocentric with the argument /', the auxiliary arc x? being between the values of / and /', will be a very small quantity in defect of the argument ; and that, on the contrary, in reducing the geocentric to the geographical latitude, the arc x w ^ exceed the argu- ment by nearly the same quantity. Therefore, if we assume x as an argument for the difference /' /, a table formed from the equation tan (l' n = or l' l On Eclipses. 57 will be equally adapted to both reductions, giving nearly the mean between them; and a table so constructed, with the argument y, signifying either latitude, will answer every necessary degree of accuracy, since the reduction itself is so small. In numbers we have and hence = 7 ' 51641 /' / = [2-83084] sin 2 Thus the following table has been derived : Difference between the Geographical and Geocentric Latitudes. Argument : x either Latitude. X I 1 I # /' / % I' I 1 II / // l ll o 90 15 75 5 39 30 60 9 47 1 89 24 16 74 5 59 31 59 9 58 2 88 47 17 73 6 19 32 58 10 9 3 87 1 11 18 72 6 38 33 57 10 19 4 86 1 34 19 71 6 57 34 56 10 28 5 85 1 58 20 70 7 15 35 55 10 37 6 84 2 21 21 69 7 33 36 54 10 44 7 83 2 44 22 68 7 51 37 53 10 51 8 82 3 7 23 67 8 7 38 52 10 57 9 81 3 29 24 66 8 23 39 51 11 3 10 80 3 52 25 65 8 39 40 50 11 7 11 79 4 14 26 64 8 54 41 49 11 11 12 78 4 36 27 6s 9 8 42 48 11 14 13 77 4 57. 28 62 9 22 43 47 11 16 14 76 5 18 29 6l 9 34 44 46 11 17 15 75 5 39 30 60 9 47 45 45 11 17 The difference is to be subtracted from the geographical, or added to the geocentric latitude, whether it be North or South. It is evident, from what has been said, page 55, that if Z denote the true distance of the Moon from the central zenith as it would appear at the centre of the Earth, and Z' the apparent distance from the same zenith, as seen from the place on the surface, where the radius of the Earth is /> ; and furthermore, P the equatorial hori- zontal parallax, and z =s Z' Z, the parallax in altitude, we shall have sin * = p sin P sin Z' - (8) Substituting Z + in the place of Z', and dividing by cos 2, we find p sin P sin Z tan z == 1 p sm P cos Z which are the usual formulae for the parallax in altitude, (9) 58 On Eclipses > / \ y1 For the radius f> of the Earth we have log A/ - ^- s= 8*909435, and .'. by (6) tan yr = [8-909435] sin / p =: cos YT The values of j> so computed are given in the annexed table. Log. Radius of the Earth. Argument : Geocentric Latitude. l logg 1 logg / log e '00000 30 9-99964 60 9-99893 1 o-ooooo 31 9-99962 61 9*99891 2 '00000 32 9 '999*0 62 9-99889 3 o -ooooo 33 9-99958 63 9-99887 4 9*99999 34 9-99955 64 9*99885 5 9 '99999 35 9 '99953 65 9 '99883 6 9-99998 36 9-99951 66 9*99881 7 9-99998 37 9-99948 67 9-99879 8 9-99997 38 9-99946 68 9-99877 9 9*99997 39 9 -99943 69 9-99876 10 9-99996 40 9-99941 70 9-99874 11 9-99995 41 9-99938 71 9-99872 12 9-99994 42 9-99936 72 9*99871 13 9-99993 43 9 -99934 73 9-99870 14 9-99992 44 9-99931 74 9*99868 15 9-99990 45 9-99929 75 9*99867 16 9-99989 46 9-99926 76 9*99866 17 9-99988 47 9-99924 77 9-99865 18 9-99986 48 9-99921 78 9*99864 19 9'99985 49 9-99919 79 9*99863 20 9-99983 50 9-99916 80 9-99862 21 9-99982 51 9-99914 81 9*99861 22 9*99980 52 9-99911 82 9-99860 23 9-99978 53 9-99909 83 9 -99859 24 9'99976 54 9-99907 84 9*99859 25 9-99974 55 9-99904 85 9*99858 26 9*99973 *6 9-99902 86 9 '99858 27 9-99971 57 9-99900 87 9*99858 28 9-99968 58 9-99897 88 9 '99858 29 9 -99966 59 9-99895 89 9*99357 30 9-99964 60 9-99893 90 9 -99857 On Eclipses. 59 PHENOMENA WHICH TAKE PLACE ON THE EARTH GENERALLY. The place on the surface of the Earth where the limbs of the Sun and Moon first appear in contact will be where the penumbra first touches the Earth, and, consequently, at this place the apparent contact will be in the horizon, the disc of the Moon being wholly above the horizon, and that of the Sun below it. The point of contact will be in the same vertical with the two centres ; and, therefore, the real as well as the apparent places will be in the same vertical circle ; and the lower limb of the Moon, being in the horizon, will be depressed by the whole amount of the horizontal parallax which belongs at that time to the latitude of the place. Similarly, the place which first has a central eclipse will be where the straight line through the centres of the Sun and Moon comes first in contact with the Earth, and at this place the centres of both objects will be in the horizon, that of the Moon experiencing the whole effect of the horizontal parallax. The same circumstances will have place where the phenomena finally quit the Earth. Since the apparent places of the Sun and Moon are so contiguous, and the parallax of the Sun so small, it is evident that the relative positions will be the same if we give to the Moon the effect of the difference of the parallaxes P ?r, and retain the Sun in his true position. This difference P it is therefore the relative parallax, or that which influences the relative position of the bodies. If p be the radius of the Earth for the place on its surface, the parallax which ought to be used is p (P T). But in the following investigations, where a place is generally the object of deter- mination, we cannot previously so reduce this relative parallax P TT. In order, therefore, to secure the chance of least deviation from the truth in this respect, we shall in these cases reduce the parallax in the first instance to a mean latitude of 45, so that it will be [9'99929] (P IT). We shall consequently, to simplify the analytical expressions, hereafter denote this quantity by the letter P' only ; except in one or two instances, where the latitude of the place is known, and where it is always distinctly specified to represent the parallax properly reduced to that latitude, or P (P-T). I. PLACES WHERE THE DIFFERENT PHASES ARE FIRST AND LAST SEEN ON THE EARTH. Let the whole be referred to the surface of a sphere concentric with the Earth ; and. let OR be the relative orbit of the Moon, which is generated by the differences of the motions in right ascension and declination, or by the relative motion of the Moon ; N, the North Pole ; S, the Sun ; S n, perpendicular to the relative orbit, the nearest approach which we denote by n ; C, the point where the Moon comessin conjunction in right ascension, and C S the difference of decimation at that time, which we shall denote by contraction, diff. dec. Let also M, M', be the positions of the Moon, when a distance of the centres equal to A ' first appears on, and finally quits, the Earth; MS = M'S = A; the corresponding true distance as seen from the centre of the Earth; Z, Z', the zeniths of these places on the Earth, which must be respectively in the continuations of M, S M', in order that the full effect of parallax may be communicated in causing the bodies to approach. 60 On Eclipses. As the apparent zenith distance of the points which experience the greatest effect must be 90, we may evidently assume Z S = 90: for contact of either limb of the Moon with the contiguous limb of the Sun, we have accurately Z S =: (90 T) + ff, a total contact first commences with A' = s a; when s < tr, an annular contact first commences with A ' = a s. Therefore, If s > = - .......... (4) A M n s= n tan w Let r denote the semiduration of the phase, or the time of describing M n y and T in seconds = c tan w Again let, at the beginning, the Z NSZ = a, and for the ending, the Z N S Z' = 6 ; and, these angles being estimated from N S towards the East, we shall have a=( &=( i)+w ........ (6) and, the Sun being supposed in the horizon, Z S = 90, Z'S = 90, cosNZ = cos NSZ sinNS cosNZ r =:cosNSZ'sinNS tan ZNS = tanZ'NS= - tan NSZ cosNS tan NSZ 1 cos N S or, sin / =2 cos a cos $ sin / ; = cos b cos J , tan a 1 tan h = : - sin 5 tan b tan k'sz : r sin 5 (7) the latitude and hour angle /, h, relating to the first place, and /', h\ to the last. These hour angles are measured from the Sun towards the East, so that the longitudes of the places will be determined by subtracting respectively from them the apparent Greenwich times of beginning and ending reduced into degrees and minutes, observing that positive differences will indicate East longitudes and negative differences West longitudes. In the preceding formulae we must use, {Partial Total Annular Central Eclipse, A s P'+S P'~* P' 62 On Eclipses. II. RISING AND SETTING LIMITS. The places Z, Z', thus found, are the two extreme points of a series of places where, at the intermediate times, the same phase will appear in the horizon; and, for the phase of external contact of limbs, the carves which these places assume form one of the principal geographical limits of the general eclipse. In the annexed diagram let M be the place of the Moon at a time between the beginning and ending of the partial eclipse. Make Sm = A', Mm ~ P', and mZ 90; then at the place Z the Moon will appear at m, and have simple external contact with the Sun in the horizon. The two triangles SmM, Sm'M will give two such places at each instantj which, on considering the passage of the penumbra over the ter- restrial disc, evidently ought to be the case. Since Mm = P' and Sm = A ', the possibility of forming the triangles SmM, Sm'M will de- pend on two conditions for the value of SM, viz., SM < Mm +.Sm, SM > Mm Sm, or A < P'+ A'and >P' A', that is, A must be between the values P' A' and P'+ A': this leads to two species of curves. 1. When the nearest approach is greater than P' A'. Here the formation of the triangles SmM, Sm'M, will always be possible during the appearance of the phase on the Earth. At the first appearance and final departure of the phase, SM == Mm -f Sm, the triangle SmM will be simply the line SM, and only one place Z will result. By taking positions of M on both sides of the middle point n, it will also appear that the relative positions of the places Z,Z', become inverted, and that the curves described by them must intersect each other at some intermediate place. Hence it appears that the curve of risings and settings com- mences with a single point, which immediately after divides itself into two points moving in opposite directions on the Earth, and which describe two curves inter- secting each other, arrd finally meeting again in a single point, the whole forming one continued curve, returning into itself, and assuming the figure of an 8 . much dis- torted. At the place where they intersect, the phase will begin at sunrise and end at sunset, or it will begin at sunset and end at sunrise. 2. When the nearest approach is less than P' A '. In this case the triangles SmM, Sm'M will resolve into the line SM when A P'+ A r and also when A :=P' A', each of which positions will give only one place Z. Thus it appears that the points Z will form two distinct, oval, and isolated curves, the former curve being generated between the decreasing values A = P' + "A ' and A = P' A ', and the latter between the increasing values .A == P' A ' and A = P' 4- A '. The leading point of the first oval and the terminating point of the second oval are the places where the phase begins and ends on the Eartn. The termi- nating point of the first oval and the leading point of the second oval are simply determined by using A = P' A ', and computing the same as for the beginning and ending of a phase on the Earth. On Eclipses, 63 Let us now turn our attention to the determination of the two places Z, Z', at any time, or for any position of M. Join Z S and draw M d perpendicular to N S. We shall, throughout our investigation, usually denote St/ by (x),d M by (y),and the Zc?SM by S, this angle being estimated from SN towards the East. To determine these quantities, let the declination of the point rf==(D), which will a little exceed that of M, and which is distinguished from it by being placed within a parenthesis; then, supposing N M to be joined, the right-angled spherical tanD triangle NdM will give tan (D) = As is always small, the difference of cos the decimations (D) D = tan" 1 D may be arranged in a small table as COS OC annexed. Difference between (D) and D, or corr. Arguments: D and . f 1 ; / f t I | j ( D 10 20 30 40 50 60 70 80 90 100 II II II ll n n II n II o i i 1 1 i 2 2 1 i 1 2 2 3 3 1 1 2 2 3 4 5 4 1 2 2 3 4 5 6 5 1 2 3 4 5 6 8 6 1 2 3 4 6 7 9 7 2 3 4 5 7 9 11 8 2 3 4 6 8 10 12 9 1 2 3 5 7 9 11 13 10 1 2 4 5 7 10 12 15 11 1 3 4 6 8 10 13 16 12 2 3 4 6 9 11* 14 18 13 2 3 5 7 9 12 15" 19 14 2 3 5 7 10 13 17 20 13 2 3 5 8 11 14 18 22 16 2 4 6 8 11 15 19 23 17 2 4 6 9 12 16 20 24 18 2 4 6 9 13 16 2-1 26 19 1 2 4 . 7 10 13 17 22 27 20 1 3 4 7 10 14 18 23 28 21 1 3 5 7 11 14 19 24 29 22 1 3 5 8 11 15 19 25 30 23 1 3 5 8 11 15 20 25 31 24 ] 3 5 8 12 16 21 26 32 25 1 3 5 8 12 16 21 27 33 26 1 3 6 9 12 17 22 28 34 27 1 3 6 9 13 17 23 29 35 28 1 3 6 9 13 18 23 29 36 29 1 3 6 9 13 18 24 30 37 The number of seconds given by this table, which we have denoted by the term corr. is to be applied so as to increase D, whether it be North or South. 64 On Eclipses. The value of (D) being found by so correcting D with this table, we shall evi- dently have (*) _. (y) ^ M sin S " " cos S (A) the quadrant in which S is to be taken being determined by (#) and (y) as co- ordinates. We shall afterwards have frequent occasion to use these quantities. If t denote the time from the middle of the general eclipse, they may be determined more easily, though less accurately, by means of the following formulae, which may readily be inferred from what has preceded. A = n cosw s = (-o + " (#) = A cos S (y) =: A sin S the upper sign being for the time t before the middle, and the under sign for the same time after the middle. Denote the ZwMS bym. In the triangle mMS, which may, on account of its smallness, be considered as a plane one, we also have Mm = P 7 , Smr=A', and S M sr A . Assume ^_ P' + A' q t= and then m sin y = P'. A (1) AsZS, Zw may be considered as quadrantal arcs, they will be parallel at the extremities S,m; and thus the ZZ SM= ZwM S=m. Therefore the Z NSZ = S + m; and the Sun being supposed in the horizon, the spherical triangle N S Z will have Z S =: 90, and hence the places Z, Z', will depend on the following formulae, in which Z is called the place advancing, and Z' the place following. Place following, sin / = cos (S m) cos S tan h _ _ tan (S m) sin 5 Place advancing, Bin / =: cos (S + m) cos tan tan (S -f m) h = . sm -(2) In these expressions the symbol S represents the declination of the Sun at the time for which we calculate ; but for common purposes the value of c) at the time of conjunc- tion may be used in all cases. On Eclipses. 65 III. NORTHERN AND SOUTHERN LIMITS FOR ANY PHASE. The determination of the extreme latitudinal limits of a phase, or of the terrestrial lines whereon that phase will appear as the middle of the local eclipse, is the most complex and unmanageable of all operations which relate to a general eclipse. For any given phase, at different places on the Earth, the Moon must be so reduced by parallax as to touch a given concentric circle on the solar disc ; and if we consider this circle, by way of illustration, to represent, instead of the Sun, the disc of the lumi- nous body, the places on the Earth which severally see the given phase must be situated in the surface of the penumbral or umbral cone, according as the interfering limb of the Moon only approaches or projects over the centre of the Sun ; that is, the places must all be found in the intersection of this cone with the surface of the Earth. This intersection will assume a complete or partial oval form, according as the cone falls wholly or partially on the Earth's illuminated disc. When it falls only partially on the Earth, the extreme points will evidently see the Sun in the horizon, and be therefore two points belonging to the horizon limits ; but in the other case the phase cannot at that instant be seen in the horizon. It is evident then, that these two cases have been already characterized in the discussion of the rising and setting limits. Let us now suppose the bodies to assume consecutive positions, answering to very small intervals of time, the Earth also turning round its axis, and we shall have a series of these ovals. It is obvious that the extreme geographical limits of the phase will be represented by curves which envelope all these ovals ; that at each instant the place of limit, by reason of the com- pound of the motions, will be proceeding relatively in the direction of the tangent to the oval ; that there will be two of these limits when the oval becomes entire during the eclipse, but only one when it is always partial. This is the most popular and natural idea that can be formed of the nature of these limits ; and we may here remark, as an inference from what has been said, that if the rising and setting limits of any phase do not extend throughout the general partial eclipse, there will be both a Northern and Southern limit to that phase; but that, on the contrary, when the rising and setting limits continue throughout the eclipse, there will be only one of these limits to the phase, viz. : a Southern limit when the difference of declination at conjunction is positive, and a Northern one when that difference is negative. As before, let the system be referred to a sphere concentric with the Earth, and let M be the place of the Moon; Z, Z', the zeniths of the places which are respectively in the Northern and Southern limits; and m, wi/, the corresponding apparent places of the Moon. Draw the meridians Nm', N S, N w, NZ,NZ'; also mr,m f r', and M h d h! perpendi- cular to N S ; and assume S d= (or), rfM (y), m h =r ,r, h M = y, S r = u, mr v, S m r= A ', Zm=rZ, ZNmZ=M, ZraNS~', declination of m = D', and the latitude of Z rr I. Then the Z mN Z = h ', m M = P' sin Z, x = m M cos M = P' sin Z cos M and y = wM sin M = P' sin Z sin M ; these by spherics resolve thus : x = P' sin Z cos M =r P' {sin / cos D' cos / sin D' cos (h ')} y = P' sin Z sin M =r F' cos/ sin (A ') On Eclipses. From these we deduce =: P' sin Z cos M (#) = P {sin/ cos D' cos/ sin D' cos (A ')} (*) = (y) y = (y) P' sin Z sin M = (y) P' cos / sin (h ') Let us now keep our attention to the same place Z on the Earth, and suppose the system to he in motion as in nature. The hour angle h will increase at the rate of 15 per hour, and the latitude / will by hypothesis remain unchanged; so that the following equations will ensue : -^ = -P'sml''^{sin/sinD'4-cos/cosD'cos(/i--')} dt dt + P'sin I" 15-. ~ cos/ sin D' sin (/i ') - dt sinl" (15 -^ sinD'sinZ sinM ~ \ dt ) dt at - cos ; cos A _ - J (cos Z cos D'- sin Z sin D' cos M) at Now, in order that m may be the apparent place of the Moon at the middle of the eclipse, and consequently her nearest apparent contiguity with the Sun, we must have - =r ; or since u*+v* = A ' 2 , u . |- v r- = 0, which is the condition of dt dt dt limit. Before we substitute the preceding values of 7, y-, it may be observed, to avoid complexity, that the quantities P'sin I" - , P 7 sin l" ^- may be neglected at at being very small compared with P', 15 sin 1", and p> also that 5 may be substituted for D', which will equally serve the purpose of both Northern and Southern limits. With these modifications we have as - = P' . 15 sin I" sin & sirrZ sin M - - = -^ PM5 sin 1" (cos Z cos S sin Z sin & cos M) and, for the condition of limit, u JP' . 15 sin 1" sin 5 sin Z sin M - ^^ 1 + V {~d ~~ P '' 15 sin ^'(cosZ cosS sinZ sin $ cos (2) M)| = On Eclipses. 67 Instead of P' sin Z cos M put (#) + u, and for P r sin Z sin M put (y) v, and it becomes ti{l5 sin I" (y) sinS- ^} + v { 15' sin 1" (*) sin $ + ^H P'v 15sinl // cosZ cos 5=0 . cog z _ [ w 15 sin 1") P y " ^ 15sinl"J But, if ! denote the true relative motion in right ascension, and D t the true relative motion in declination, and D the declination of the Moon, at the time of true con- junction, jf*\ ,if n ,\ = i cos D dt W f F {^ /. COS Z =2 ' V ( . . i COS D Bm ~ + * sm s + V COS C Make now the following assumptions : (A) + (a) sin J X COS V = - =r - - - P r cos $ in which (A), (B) may be used as constant quantities throughout the eclipse, and we get cos Z = ( wsinv + v cos v) v The angle rSm is equal to the inclination of the apparent relative orbit with the parallel of declination ; denote it by t', and then u = A ' cos t', v s= A ' sin i', and X7 ......... (4) sm i' which is a concise form of the condition to be fulfilled by Z and t', in order that the place Z may be situated in the limit of a phase. Since the Z MSd = S, and the Z MSm = 180 (S + i')> Z MSm'=S + i', we have for the triangle MSm Mm 2 = A 2 + A /2 2 A A '008(8 + *') Divide this by P' 2 and we get for the geometrical relation between S and t', the upper sign applying to the Northern, and the under sign to the Southern limit. Add this to the square of the preceding equation (4), and there results 68 On Eclipses. = 1 - - - (6) f for the determination of the angle i'. The solution of this equation is by no means very practicable ; but as a small error in the value of Z will not sensibly affect the angle i', we may have recourse to the following indirect process, in which we first consider the angle t' to be equal to t, which in most instances is very nearly so. The letter M designates the angle Mm/t. D' = S + u v u = A ' cos i v = A ' sin i ' = + tan M = x - cos D' (D) =D + (-') corr. -= ( a _ a ') cos (D) x = (D) D' * y sinZ = (7) P'cosM P'sinM the upper signs being for the Northern, and the under signs for the Southern limit. Or, if t be the time from the middle of the general eclipse, and w' the angle under Mm and the line of nearest approach, we shall have Mm sin u 1 = n tan w =r n , and Mm cos + p/. 15 sin l"sm* dt dt dt dt Let p, denote the hourly motion on the apparent relative orbit, and i f the inclination with a parallel of decimation ; then > cos t! = , /* sin $, we can previously correct the horizontal parallax for the place by reducing it to a latitude equal to the complement of $. The value of t being found, we shall have at the place When diff. dec. and 5 navej^^j signs, app. time of true J = j l ^\ t- - (4) which compared with the Greenwich apparent time of the true conjunction will show the longitude of the place. For the values of u and v we have u = ( diff. dec. + P 7 ) t D t = k cos (i' i) k sin t 7 sin t = k cos t' cos t v =s t i cos D ~ t D! cot t k sin i r cos t Let n' be the nearest apparent approach of the centres ; and the semiduration T will be determined by the equations v n f A 'sin w sin i' U' = - - COS tit = - r r = - D r and thence the latitude by the equation, tan / = + - ^- - tan ^ Or, using the above value of v, k cos i A'sinw , cos (r. 15) cos co t=r r - - tan/= - . . - - (5) A /* tan d the latitude being of the same name as diff. dec. The middle of the eclipse will not have the Sun in the horizon, except k cos t = A r , T ~ 0, / = 90 S, and therefore, unless these particular values should happen, the place will not range exactly in the line whereon the middle of the eclipse is seen at sunrise or sunset; this line, which we are about to notice, will pass the intersection at a higher latitude, and will form a very small triangle with the Rising and Setting limits. f2 72 On Eclipses. V. PLACES WHICH WILL HAVE THE MIDDLE OF THE ECLIPSE WITH THE SUN IN THE HORIZON. In the first place, we shall suppose the inclination of the apparent orbit to be the same as that of the true. The condition for the middle of the eclipse will then be simply to have the apparent place of the Moon somewhere on the line of nearest approach. On both sides of S take Sm = Sm', = s + 90 when diff. dec. is negative These semidurations will give two times of beginning and ending; the one answering to the point M and the other to the point M". The middle of an eclipse in the horizon will take place from the first beginning to the second beginning, and from the second ending to the first ending. The places will be detennined by producing m M to a distance of 90 from m. If a great circle be drawn through S, so as to be at this point parallel to wM, it will evidently intersect the former at a distance of 90 and determine the same place. We shall therefore, in supposing the places to be determined in this manner, have the following formulae : On Eclipses. 73 First place of beginning, w t 90 ] cot i /r ,v sin / = sin i cos $ tan & = : r > (2) sin h must be taken in the 2nd semicircle, or between and 180 J First place of ending, Change the name of the latitude of the place of beginning, and to the hour angle h apply +180. The results will determine the place of ending. Second place of beginning, tan a sm / = cos a cos tan h = : 5 sin o Second place of ending, tan b sin I = cos 6 cos d tan ft r= : r sin d (3) The second places of beginning and ending will be two of the extreme points of the lines traced on the Earth. The other two extremes may be determined by com- puting cos w == ~ and proceeding as before, observing that n must be considered positive, and w > 90 when diff. dec. is positive. These four extreme points are the same as those of the Northern and Southern limits, the phase being simply external contact. (2) WHEN n >P' (s + - (4) found as above. (3) WHEN n>s + 90 when - (5) diff. dec. is negative. The phase will continue throughout the whole duration, and the extreme places may be computed from this value of w according to the equations (3). Having found the limits between which the phase is possible, the places for any intermediate times may be determined thus, t denoting the time from the middle, (i) > 90 when diff. dec. is negative, and the places by the equations (3). If n < s + ff, suppose n to be positive, and compute cos it) r = I ) sin a; 74 On Eclipses. Then for times, without the limits of this duration, we may determine four places; two with o><90 and two with ^>90, which will all fulfil the necessary con- ditions. The preceding results have been derived on the assumption of i' = i. They will be sufficiently approximate for a general drawing of the lines on a map, and more particularly as these phenomena cannot be subject to minute observation. When, however, from local circumstances or otherwise, greater accuracy is wanted, we must use the proper value of t f and the relative horizontal parallax reduced to the latitude thus determined. Since Z = 90, the condition for the middle of the eclipse, according to the equation (4) page 67, is i' v = or 1' = v. Let the figure at page 65 repre- sent the positions which answer to the particulars of the present case. Then as Mm = Mra' = P', the ZMrara'^Z Mra'w. Denote this angle by 0; the angles NraM, Nra'M by M,M'; and we shall have ZNmS = v ZNra'S = 180 v M.~0-~v M'=180 v ZMSra= 180 S > ZMSra' = S + v ZSMra = S + v ZSMra'" 180 (S + v + 0) With the triangles MSm, MSra', we hence find sin =2 sin (S + v) -*) si which, for computation, may be thus arranged : sin (S + v) ~ ~ - - to be + or but less than 90 C ' --(6) M '= The points m, m ; , may in some cases be both on the same side of S, and the value of S m is only necessary to indicate whether any portion of the Sun is eclipsed or not. To have an eclipse, Sra, taken as a positive quantity, must be less than s + the middle of an eclipse cannot be seen on the Earth under the assumed con- ditions; on the contrary, if Sra, Sra' so taken are both less than s + a, the angles M, M' may both be used, and consequently two places will be determined. In each case, similarly to (3), we adopt the formulae sin / =r cos M cos S tan h == -- - [ - - - - (7) On Eclipses. 75 VI. CENTRAL LINE. The places which in succession see a central eclipse are evidently determined by producing S M to a distance Z from S, so that inZ = ~ (1) for then the relative parallax P' will bring the centres to a coincidence. To determine the position of the place on the Earth for any given time we have in the triangle NSZ, thus formed, NS==90 S, Z NSZ = S, SZ = Z, and hence the following formulae tan 6 = tan Z cos S e to be + or and less than 90 tan h = . tan S tan I = tan (0 + 5) cos h COS {9 + o) h to be in the same semicircle with S sin Q sin Z cos S check - - cos (0 + ) ' cos h cos I - ' (2) In the course of the general central eclipse, one of the places on the Earth will have the central eclipse at noon. At this instant the bodies will obviously have true as well as apparent conjunction in right ascension, and .*. A = diff. dec. and S = 0. This place is hence determined thus: diff. dec. sm z = / = a + z }> (3) Z to have the same sign as diff. dec. App. time of true 6 = West Long, of place These equations (1), (2), (3), involve the horizontal parallax P', answering to a mean latitude of 45, which will be sufficiently near for ordinary purposes. Where an accurate result is wanted the calculation must be repeated with the use of the equatorial relative parallax properly reduced to the latitude thus determined. The first and last places on the Earth, which see a central eclipse, are to be found by the formulae at pages 60 and 6l. The preceding discussions comprise all that is necessary for the calculation of the lines which are shown in the maps now inserted in the NAUTICAL ALMANAC, and which are quite sufficient to indicate the general character of the eclipse that may be expected for any particular place. We might now proceed to show the application of these equations in the resolution of innumerable other curious and interesting problems; but such a field of speculation would not conform with the object of this paper, and may the more willingly be abandoned on the consideration that the means of solution may, in most cases, be readily elicited from the equations already established. The following classification of these equations will be found to exhibit, in a comprehensive form, all that will be requisite to direct and facilitate the operations of the calculator, and relieve the mind from any unnecessary reference or consideration. 76 On Eclipses. NOTATION. I) = the J) 's true declination. S = the O 's true declination. t= the true difference of right ascension in arc, or }) 's right ascension O's right ascension. D! =2 the }) J s relative motion in declination, or }) 's motion in declination O's motion in declination. ! er the }) 's relative motion in right ascension, or the motion of the }) that of the . Diff. dec. = the true difference of declination at d in right ascension, viz. }) 's declination O's declination, at that time. P r the }) 's equatorial horizontal parallax. v =r the O's equatorial horizontal parallax. P'= [9-99929] (P-). s = the }) 's true semidiameter. P'- A 7 These limits will extend throughout the entire duration of the general eclipse, and form the distorted figure of an 8, the first and last points being the places of begin- ning and ending on the Earth. 8. When n

90 when n is 10. for { b a t?} *e time of middle 11. to be less than 90 and positive 12. Place following, .,_ tan (S m) sm/ = cos(S m)cos5 tan h = - r sm ^ H = Apparent Greenwich time Longitude E. = h H h to be in the same semicircle with S m 13. Place advancing, tan (S + m) sin / = cos (S + m) cos J tan h = - Longitude E. = h H h to be in the same semicircle with S + m 14. FOR A MORE ACCURATE DETERMINATION, Find the values of D, $, P' A '. 15. Find P' =/> (P ), for a latitude equal to the complement of $ at 6 . /* sin i' = D! /* cos i' =; ! cos D + [9*41796] P 7 sin 5 diff. dec. + P' . K *o^ * sin l k = 7-: = < zw seconds = [3'55030] cos (i 7 i) /* 16. At the Place, When diff. dec. and $ have {Afferent 6 } signs ' app * time of true 6 = { ^^l ~ * which compared with the Greenwich apparent time of the true 6 , will determine the longitude of the place. 17. k cos i _ A' sin w A 7 /* > 4- O * tan 5 / to be of the same name as diff. dec. 80 On Eclipses. IV. PLACES WHERE THE MIDDLE OF THE ECLIPSE IS SEEN WITH THE SUN IN THE HORIZON. 18. When n < P' (s + P' (5 + s + cr, compute 90 when diff. dec. is negative. The places to be determined by proceeding with o> as for the beginning and ending of a phase. 22. FOR A MORE ACCURATE DETERMINATION AT ANY TlME, Find P' = j> (P T) for the latitude before found. Find (#), (y), S and A as in No. 14. For the time of 6 form the constants (A) = [0-58204] Wl cos D (B) = [0'58204] D, Compute v from the equations (A) + O) sin S (B) (y) sin I \ cos v = } T v ' X sm v = '. ^ P' cos S P' cos I 23. Then sin _sin(S + ^ to be + or but less than 90 24. . ; _ tanM sm / = cos M cos S tan h = : r- smS If K 9 K' be both less than s + ff, the angles M, M 7 may be both used in these equa- tions, and two places determined. If one of the quantities K, K 1 be greater than s+v, the Corresponding M will be excluded, and only one place determined with the other value. If P' A 7 only one limit will have place, viz. 26. FIRST AND LAST POINTS OR PLACES OF ENTRANCE AND DEPARTURE. n+ A 7 /cP' -= Places of entrance and departure determined as in Nos. 4 and 5, for the beginning and ending of a phase, using a = ( t) w and b = ( t) + w. For the appearance of external contact these determinations are included in No. 18, and therefore need not be repeated for these limits. 27. PLACES FOR ANY TIMES WITHIN THE LIMITS. Prepare the following constants, using S at 6 , / TV X ~~ / _ _r_ A ' s * n l u ~~ A C a ""-*- cosD' n n+ A 7 n. 7* -t- f\ ' E = c(n+A') 28. Let t be the time from the middle of the general eclipse cos w tan w 1 = t . E cos w M=(-0+ w/ 29. tan 6 = tan Z cos M n M tan / sine sin Z cos M tan (/i ') = - 1 ^ tan M tan / = tan (6> + D 7 ) cos (h 7 ) " cos (6> + D') cos (h 7 ) cos / < 90 and same sign as cos M ; and h ex 1 to be in the same semicircle with M. On Eclipses, 83 30. FOR A MORE ACCURATE DETERMINATION AT ANY TlME, Find P'~/> (P T) for the latitude before found. Also, with Z find the augmented semidiameter s' = s + augmentation, from the table annexed. Augmentation of the 3) 's Semidiameter. Argument True Zenith Distance Z. For P Var. for ForP Var. for For P Var. for Z = 54' 10' in P. Z = 54' 10' in P. Z = 54' 10' in P. o ii n o // /; n n 14*0 5-7 30 12 '1 4-9 60 6-9 2-9 1 14 '0 5-7 31 12*0 4-8 61 6'7 2 '8 2 14 '0 5-7 32 11-9 4-8 62 6-5 2-7 3 14-0 5-7 33 11-7 4'7 63 6-2 2-6 4 14 '0 5-7 34 H-6 4'7 64 6-0 2'5 5 13-9 5-7 35 11 '5 4-7 65 5 '8 2 '4 6 13'9 5-7 36 11 '3 4-6 66 5-6 2'3 7 13-9 5-7 37 11 '2 4-6 67 5 -4 2'2 8 13*8 5-7 38 11 '0 4-5 68 5 -2 2 '1 9 13-8 5-7 39 10-8 4-4 69 4-9 2*0 10 13'8 5-6 40 10-7 4.4 70 4'7 1'9 11 13-7 5-6 41 10-5 4*3 71 4-5 1-8 12 13-7 5-6 42 10-3 4'3 72 4-2 1'7 13 13-6 5-6 43 10 '2 4 '2 73 4 '0 1-6 14 13-6 5-5 44 lO'O 4-1 74 3 '8 1 '5 15 13'5 5-6 45 9'8 4-1 75 3-6 1 '4 16 13 '4 5-5 46 9*7 4'0 76 3 '3 1*3 17 13'4 5 '4 47 9*5 3-9 77 3 '1 1'2 18 13*3 5'4 48 9'3 3-9 78 2-8 1 *1 19 13*2 5*4 49 '2 3'8 79 2-6 I'l 20 13'1 5 '4 50 9-0 3-7 80 2 '4 i -o 21 13 '0 5'4 51 8 '8 3-6 81 2'1 0-9 22 12 '9 5 -3 52 8'6 3'5 82 1*9 0-8 23 12-8 5 '3 53 8'4 3 '4 83 l'7 0-7 24 12 '7 5'3 54 8'2 3 '3 84 1 '4 0-6 25 12-6 5-2 55 8'0 3'2 85 1 *2 0-5 26 12 '5 5'1 56 7'8 3*2 86 1 -0 0-4 27 12'4 5-1 57 7-5 3'1 87 0-7 0'3 28 12'3 5 '0 58 7'3 3-1 88 0-5 0'2 29 12 '2 4.9 59 7'1 3-0 89 0-3 O'l 30 12 '1 4-9 60 6-9 2-9 90 o-o o-o Then, f Partial ) ( s' + 90 when n is negative 35. S = ( t) + On Eclipses. 85 36. A sill Z = tan h =r sin0 check - - - - cos (0 + d sin (S at d ) tan = tan Z cos S tan S tan / = tan (9 + S) cos h sin Z cos S cos (Q -f S) cos h cos / , same sign as cos S, and less than 90' , same semicircle with S. 37. FOR A MORE ACCURATE DETERMINATION AT ANY TIME, Find P', S, A , as in No. 14, and proceed again with these as in No. 36. 38. PLACE WHERE THE ECLIPSE WILL BE CENTRAL AT NOON. (S at 6 ) cliff, dec. sin Z = , / = 5 + Z Apparent Greenwich time of true <5 = Longitude W. Z < 90 and same sign as diff. dec. 39. For a more accurate determination find the horizontal parallax for the latitude and with it repeat the operation. %* All latitudes in the preceding formulae are to be recognized as geocentric, and will therefore need reducing by the table at page 57. NAUTICAL ALMANAC, 183G. APPENDIX. 36 On Eclipses. EXAMPLES. For an elucidation of the practical application of the preceding formulae we shall take the Solar Eclipse of May 15, 1836. At the time of New Moon, viz. 2 h 7 m '0, the Moon's latitude ft is 25' 43", which being less than 1 23' 17" the eclipse is certain. See the limits at page 55. The elements of this eclipse, as related to the equator, are Greenwich Mean Time of 6 in R. A. May 15 2 21 22 -9 }) 's Declination - N. 19 25 9 '8 O's Declination N. 18 57 58 '8 D 's Hourly Motion in R. A. ------- 30 8 '3 O's Hourly Motion in R. A. 2 28 *2 3) 5 s Hourly Motion in Declination - - - - N. 9 58 '7 J s Hourly Motion in Declination - - - - N. 35*1 }) 's Equatorial Horizontal Parallax ---- 5423*9 's Equatorial Horizontal Parallax - - - - 8 '5 3) 's True Semidiameter 14 49 '5 's True Semidiameter 15 49 '9 from which we prepare the following values : O I II I II 2)'sDec. - - + 19 25 10 }) 's H. M. in R. A. 30 8 0's Dec. - - + 18 57 59 0'sH.M.inR.A. 2 28 Diff. Dec. + 27 11 i 27 40 3) 's H. M. in Dec. + 9 59 }) 's Eq. Hor. Par. 54 24 0's H. M. in Dec. + 35 0's Eq. Hor. Par. 9 D! + 9 24 Rel. Eq. Hor. Par. 54 15 log. - 3 '51255 const. 9'99929 P' - - 54 10 log. - 3-51184 I. BEGINNING AND ENDING ON THE EARTH. D, + 9' 24" 275128 (1) ! 27 40 3 -22011 9-53117 D + 19 25''2 cos 9 '97456 ftan 9-55661 (2) e +1Q 49 - - J jcos - - - 9-97349 (3) diff. dec. + 27' 11" - 3 -21245 n + 25 34 3-18594 sin t - - 9 '53010 (2) + (3) const. - - 3-55630 6 -27234 (4) c 3-52106 (4) (1) t - - + 19 m 56* - - c tan i - - 3 -07767 (5 - 15 2 21 23 15 2 1 27 - Middle of general eclipse On Eclipses. 87 p/ 54/ 10" A for Central Phase + ff - - 30 39 84 49 = A for Partial Phase r - Partial n - - + 3 -18594 A - - 3 70663 fcos - jtan- + 9-47931 -49999 c - - 3 '52106 d h m a ________ 2 54 57 - - 4 -02105 15 2 1 27 14 23 6 30 Beginning 15 4 56 24 Ending (-0 19 49 w - - - 72 27 92 16 - - - + 52 38 49' | T - Central n - - - A - - icos - - tan - c - - h 3 -18594 3 '51184 dog.P') h 9*67410 o -27109 3-52106 1 43 17 - - 3 '79215 15 2 1 27 15 18 10 Beginning 15 3 44 44 Ending (__) 19 49 u - - - 61 49 a ---- 81 38 ... + 42 PLACE OF PARTIAL BEGINNING. cos a 8 -59715 cos S - - + 9 -97576 tan a sin 5 tan h h H HI "40251 - + 9-51191 sin / 8 -57291 . . i -89060 / - - S. 2 9 7 Reduction 1 89 16 7 347 37 Greenwich time 23 6 30 Equation - - 3 56 Hin {time - - - 23 10 26. space - - 347 37' Latitude S. 2 10 Longitude W. 76 53 In the same manner may the places of Partial Ending, and Central Beginning and Ending, be calculated, which will come out o / o / Partial Ending - Long. E. 28 51 Lat. N. 35 13 Central Beginning Long. W. 98 16 Lat. N. 7 58 Central Ending - Long. E. 52 41 Lat. N. 44 50 II. RISING AND SETTING LIMITS. P 7 54 10 23 31 84 49 / // p?=. 11 46 q = 42 25 Since n > P' A ', these limits will extend throughout the whole duration of the eclipse ; and we may therefore calculate the position of a place for any time between the Greenwich times 14 d 23 b 6 m 30 8 and 15 d 4 b 56 m 24 s . As an Example take the time 15 d O h 30 m . 88 S m S +771 Assumed time - Time of Middle On Eclipses. d h m a 15 30 - - - - 15 2 1 27 3.*7 o no o 1 I / o . c .-> i n A 1 19 49 / {foYl - O.p i op 7 58 51 u> - . - 58 *) 1 78 40 34 2 3'J.*7 1 O 1 112 42 i A pi j p flog A - - - 44 38 " A p 12 56 A - - - - 17 43 - - 2-88986 Comp. log P 7 - - 6-48816 o / 2)18'93264 %m 17 *9 m 34 2 sin PLACE FOLLOWING. h m a cos (S m) 9*58648 tan (S m) + 0*37850 Greenwich lime 30 cos S - - - + 9*97576 sin 2 - - - + 9 '51 191 Equation - - + 3 56 time 33 56 sin / - - - 9-56224 tan h - '86659 / S. 21 24' h - 82 15 7 Reduction - 8 H - 8 29 1 H in \space 8 29' Latitude- - S. 21 32 Longitude- W. 90 44 PLACE ADVANCING. cos (S-fw) - - + 9 -85225 T y y/<>jv 9'SOSOl I 4P i o Reduction - 11 tan (S+m) 9 '99444 sin $ +9 '51191 tan h -4 h II + o '48253 ~108 13 Latitude - - - N. 42 29 Longitude --- W. 116 42 By taking S = ( t) + w instead of ( w, similar computations will give the places following and advancing for the interval t = l h 31 m 27* after the time of middle, or for the Greenwich time 15 d 3 h 32 m 54 s . Much time will be saved by taking the computations two and two in this manner. 1II.-PLACE WHERE THE RISING AND SETTING LINES INTERSECT. o / 90 o - - 18 58 / - - 71 2 On Eclipses. 89 p - - 9 '99872 P v - - 3 '51255 P'- - 54' 5" 3 '51127 sin - + 9*51191 const. - - 9'41796 + 4 36 +2 '44114 ^ . . - . 3 -22011 cos D - - 9 '97456 26 6 3 -19467 30 42 r= /i cost' - - + 3/26529 .- + 2-75128 - +~9~'48599 - + 9 "98056 - . - . +3 -28473 + 26 54 - + 3'20790 cos (t'-~ c) - - 9 "99948 k \- 3 -20842 +3 -20842 cost- - +9'97349 sin i h 9 '53010 3 -55630 + 3 '18191 3 '26458 + 6 -29482 cos w - - 9-91733 log; - - - +3'01009 sinu, - - 9 75036 h~~^- 3-01494 --- 3 '28473 12 T- 9-73021 App. Time true c$ 1 1 42 56 at the place 15 2-95424 ~~h m 7 2 21 23 8 4' - - _2j68445_ Equation 3 56 cos 9^99568 App. Time true 6 2 25 19 at Greenwich f time 9 h 17 m 3T ) T tan / - - -45953 Long, in { r } E. \space 139 84' J / - - N. 70 5l' Reduction 7 Latitude N. 70 58 Thus we find the required place to be in Longitude E. 139 24 r and Latitude N. 70 58', where simple contact will have place at sunset and again at sunrise; also the middle of the eclipse would be seen at midnight if it were not intercepted by the opacity of the Earth. The duration of the eclipse will correspond with the duration of the night, and therefore no portion of it will be visible. 90 On Eclipses IV. PLACES WHERE THE MIDDLE OF THE ECLIPSE HAS THE SUN IN THE HORIZON. In the present case n is >P' (-J+<0 and <.$+&. We must therefore proceed as in N 19. 1 . For the extreme Points, c - - 3-52106 P'- - 3 '51184 + 25 34 3 '18594 cF 30 39 - 3-84696 (1) 5 5 2 -48430 P'- - 3 -51184 . cos 8 '97246 - - 95 23' sin 9 "99808 (2) (0 19 49 7 3 - - 1 56 39 3 -84504 (1) + (2) o> 8 95 23 21 27 time of middle a 115 12 0448 time of beginning b + 75 34 3 58 6 time of ending PLACE OF BEGINNING, OR FIRST EXTREME PLACE. h m s cos a 9 '62918 tan a - - + '32738 Greenwich time - 4 48 cos $ + 9-97576 sin $ - - + 9-51191 Equation- - - - 3 56 time 8 44 sin / 9 -60494 tan h - h - H - '81547 / S.23 45 Reduction 8 o / 81 18 - + 2 11 . /ti in { I S space 2 11' Latitude S.23 53 Longitude W. 83 29 PLACE OF ENDING, OR LAST EXTREME PLACE. cos b +9 -39664 tan b - - + '58943 Greenwich time - cosS + 9*97576 sin $ - - + 9*51191 Equation- - - - sin/ + 9-37240 tan h 1*07752 f time H in / N.lsV h - - + 94V Reduction 5 H - - 60 31 Latitude N. 13 43 Longitude E. 34 16 On Eclipses, 91 2. For the extreme Times, cP' the value of r l taken out from the preceding logarithm of is l h 57 m 10*. n 2 1 27 time of middle 1 57 10 - - r l 4 17 first appearance 3 58 37 last appearance PLACE OF FIRST APPEARANCE. sin i +9 -53010 cos +9 -97576 sin I 9 '50586 I S. 18 42 Reduction 7 cot t - - + -44339 sin S - - + 9 -51191 0-93148 Greenwich time - Equation - - - - time o ; h - - 83 19 H - - + 2 3 f ti H in I I si space Latitude S. 18 49 Longitude W. 85 22 PLACE OF LAST APPEARANCE. Latitude N.I 8 49 h- H o / 83 19 180 96 41 60 38 Longitude E. 36 3 Greenwich time - Equation - - - - time H in I space 3 58 37 3 56 For the computation of places in this line, we have therefore the whole range between the Greenwich mean times O h 4 m 17* and 3 h 58 h 37 s . As an example, take the time l h 30 m . Time of Middle 2 l 1 30 cos a - - + 9*91132 cos S - - + < sin / . - 4. 9 -88708 / - -' - N. 50 27 Reduction - 11 o 31 27 : <-.)- -"-19 49 ?- 3 ' 846 9 6 15 34 - - sin - 9 '42881 a . . . 35 23 b 4 15 tana 9 '85140 sin 5 - - + 9 -51191 tan h - - h m s Greenwich time 1 30 Equation - - - 3 56 0-33949 h - - 114 35 H - - + 23 29 Hinf l s l time 1 33 space 23 29' Latitude - N. 50 38 Longitude W. 138 4 )2 On Eclipses, By similarly using the angle b we shall find the position for the interval 31 m 27' after the time of middle, or for the time 2 h 3~2 ra 54 s ; thus, Greenwich time 2 32 54 Equation - - - 3 56 cos b - - gin / - - + 9 "99880 + 9'97576 tan b - sin - tan h - 8 -871D6 - + 9-51191 + 9-97456 - + 9-35915 / - - - N. 70 35' Reduction - 7 Latitude - N. /O 42 h 167 7 H - - + 39 13 206 20 153 40 H in time 2 36 50 space 39 13' {W F The places may be computed by two together in this way ; and it will perhaps be a little more convenient to assume a value of t in the first instance. We may take any value which does not exceed r t or l h 57 m 10 s . In the present example we should take =:31 m 2/ s , and begin as under: (-0 IV o ; - 19 49 - 15 34 35 23 4 15 log t - - 3 ^7577 rP' 3 '84696 n sn - - .9 '42881 and then proceed for the places as above. Time of middle - - - / h m s 2 1 27 Q 1 27 O 1 & j Time before middle - Time after middle - 1 30 2 32 54 V. NORTHERN AND SOUTHERN LIMITS. 1. FOR THE PARTIAL PHASE, we have only Southern Line of Simple Contact, Constants E, cos w, D', '. i // s + 6" 14 56 ff 15 50 A' - --- 30 46 n - - - + 25 34 - - - + 3 '18594 n _ A' - ~512~ 2*49415 0-69179 c - - - 3 -52106 - - 2 '49415 P' 3 '51184 E 7 -17073 cos w 8 '98231 A' 3 -26623 cos i +9 ^7349 log u -f 3 -23972 u - - 28 57 S +18 57 59 D' +19 26 56 - - - 3 -26623 sin i +9 -53010 + T-79633 cosD'-f 9 '9/448 log ' 2 '82185 o! 11' 4 /; On Eclipses. 93 The extreme places will be the same as those which have the middle of the eclipse with the Sun in the horizon, page 90 ; and we may compute for any time between the corresponding times of beginning and ending, viz. O h 4 m 48 s and 3 1 ' 58 m 6 s ; or we may take any value of t less than l h 56 m 39 s . For an example take < = h 58 m 33". h m s 01 t - - 3 '54568 Time of middle - - 2 1 27 ( t) 19 49 E 7 '17073 u/ - 100 53 tan u' 71641 Before middle 1 2 54 M 120 42 cos u>' 9'2757l After middle - - - 3 - - - M + 81 4 cos w 8 '98231 7 4- ) + 23 6" + 3-14176 p _ 3 -51255 (*) - - + 35 cos(D) + 9-97419 P . 9-99901 log (a-) - sin J - - + 3 -32222 4- Q '51 208 log (y) - + 3 -11595 + 9 '51208 P/ ros ^ - 3-51156 Q -Q7574 J 3 j <* /* + 2 -83430 + 2 -62803 P'cosS- - 3 -48730 (a;) sin (A) - - + 11' 23" + 1 39 40 (y) sin S (B) - - + .7' 5" + 35 54 cos Z - - - 2 \ cos i' - 9 -80331 o -63740 + 1 51 3 f H- 28 49 sin 2 0- - - 9-16591 log + 3 -82367 3*487^0 {log + 3-23779 3*48730 sin - - - 9 '58296 2 30' 4 4 >. f-~0 35 48 M - , - - + 30 57' -1 Z - - - - + 50 27' '9 - a 1 a - -- - fa a' - - + 22 47 \log + 3-13577 -cos - - + 9'97419 tan - - - cos - - - P' 3 -10996 3 -33203 9 '77793 9 '93328 + 3 -39875 + 3 -51156 sin - cos - - - + 9-88719 h 9 -80383 . . _ 4. D/ - - + + D' + o 46 65 5-8 + 45 42 -3 tan Z cos M - - - - + -08336 '+ 9 "93328 tan Q - - - - + o -01664 sin e + 9 -85764 + O f\(> A QQ y o^yy lanM- + -23265 + 977793 tan - - - - + -01058 + O *S44 1 P tan (6 + D') y OTi-i i < + '33249 tan / - - - - + 0-1766I / NKAO on/ .e Reduction - - D(J ~U O 10 '4 Latitude - - N. 56 30 '9 Sin Z +9 '88719 cosM h 9 '93328 + 9 '82047 comp.cos(A *') + -15588 comp. cos / - - + '25630 - check + -23265 Greenwich time Equation - - - [time - - + 3 15-23 Hin [space - - + 4850'-8 45 42 '3 Longitude - - - W. 3 8 -5 98 On Eclipses. VI. CENTRAL LINE. We have, at page 87, found the semiduration of the central appearance on the Earth to he l h 43 m 17", which is therefore the greatest value of t for this phase. As an example for a time within the limits take the same value of t as in the two preceding examples. h m . o / *- - - - - 3-62325 c 3-52106 Time of Middle / _ 2 I I 1 27 n (-0 19 Cl 49 A -I Before Middle - After Mirl flip . * 51 11 27 97 - s - - . a . _i_ 71 31 30 19 tanw - - - '10219 cos w - - - 9 '79246 rc 3-18594 A 3 -39348 p/ 3 -51184 J - Remaining computation for the time 3 b 11 m T *? 27. \ tan Z - 0994 tan Z - - - - + 06994 sin Z - - - - + 9 88164 cosS + 9 92905 cos S - - - - + 9 92905. 1 A - - - + 44 56'0 tan0 - - - - + 9 ^99899 + 9 81069 1 10 *C () "* ^ ""I"" 1 *J O U sin 6 - - - - -f 9 84898 comp. cos A - - + 15009 4- a - + 63 54 -0 9 64339 comp. cos / - - + 24480 4. 20559 - - check - - - + 20558 tan S - - - - + 9 79354 ftan A - - - - + 9 '99913 4- 44 t;A A. 1 I i m s -f t 1 * l)\J V \cos A - - - - + 9 84991 Greenwich time 3 n 27 tan (0+5) - + 30990 Equation - - - 3 56 tan / - - - - + 15981 Hin| time " " 3 15 23 N.55 18''7 n in< [space - - + 48 51 T? p rln /> +1 on _ i n A /, i 44 57 XvcClU.CtJ.Ull Latitude - - - M. \J \-f N.55 29'- Longitude - - W. 3 54 A MORE ACCURATE CALCULATION. / // ex. corr. -7- * J ou */ i f IP cosD - - - "P fc 1.1 M. 1 \J + 9-97419 ^ - - + 18 58 28 ()---- + 3-11595 (X) - + 35 - <*) + 3 '32222 P-* 3'51255 s... + 3io 52 '. 7 {^ s s ;:: + 9 79373 + 9*92899 p - - 9 '99903 A - - - - + 3'39323 F. . 3 '51 158 Z ... + 4 9 35'-6{f ; f 9 -88165 + 0-06994 On Eclipses. 99 tanZ - - \. o '06994 sin Z - - - - H h 9 '88165 e 1 u 44 cos S - - / 55 '8 tan - - - - + 9'92899 cosS - - - - H H h 9-92899 - - + 9 '99893 h 9 '81064 & - - - H + $ - H - 18 - 63 58-5 sine - - . _ + 9 -84895 + Q *6433 1 comp. cos h - - J comp. cos / - - H - - check - - - H h 0-15020 - '24480 + '20564 h '20564 tan S - - - - + 9-79373 h - - - H h 44 / Ttan h - - [cos h - - tan (0 + < tan 1 - - i - - + 9'99937 _ . + 9 -84980 5) . + -31000 Greenwich time Equation - - - {time - - - space - - - h m 3 11 27 3 56 - - + 0-15980 Nr>50 10 .7 h 3 15 23 h 48 50''8 1-44 5*7 '5 1O 'ft Latitude - - - N. 55 29 *3 Longitude - - W. 3 53 '3 CENTRAL ECLIPSE AT NOON. DiflT sin / x' z 1 1 Therefore, as cot h 1 = , tan D ; - sin A', = sin P, we find NAUTICAL ALMANAC, 1836, APPENDIX. h 102 On Eclipses. cot h 1 = cot h p sin P cos / - - ; - cos D sm /i Or, -~, / p sin P sin A sin A' tan D' = ( 1 - - - - tan D \ sm D J sin h * A -**'=/ e^L* \cos D sm tanD _ tan D'/ j> sin P \ sin h sin h' ~~ \cos D sin h) ^ (1) which present a direct method of calculating the apparent position of the Moon, at any time, from that of the true. The former of these equations is evidently subser- vient to the other, and must necessarily be computed first. As the calculation of these expressions will, in general, require seven places of figures, it will be more convenient to determine the simple effects of the parallax, or the small differences A.R. A.R.', D D', for which other expressions may be derived from them. Let A.R. A.R.' ==: h' h = A h y and D D' = A D ; then by multiplying the equation i. L M. n p sin P cos / cot h cot h' = - cos D sm h by sin h sin h', the left-hand member will become sin (h 1 h) or sin A h. Again we have . p sin P cos / . . * . sin A h = sm h 1 cos D tan D tan D' sin h sin h 1 . f sin P sin I cos D But tanD tanD' tan D tan D' sin h sn sin h sin (D (J__JL\ anI y \ sin h . sin h 1 J sin /*' sin h sin h cos D cos D' sin h sin h 1 sin A D 2 sin % A h cos (h tanD' A/*) sin A cos D cos D' Equate this with - =- : - , and we find cos D sm h sm h sin h' tan sin AD cos D cos D' j> sin P sin cos D 2 sin A A cos(/i + i A A) sin D' sin h' sin A A p sin P cos / sin h 1 But 2 sin % A A = = * - - - r cos is A n cos D cos A A Substitute this value and multiply by cos D cos D', and we deduce cosD' sin A D = p sin P ! sin / cos D' cos / sin D 7 cos (// (A + iA/0 1 cos \ A A J On Eclipses. 103 We shall therefore have, for the parallax of the hour angle, and that of the de- clination. (P cos/) sinP sin A ft = 1 -^ sin h' cosD sin A D = sin P \( f sin 1) cos D' - (o cos /) sin D' cos A (2) These are still however not adapted for direct calculation, since they involve the apparent quantities ft', D', which it is our object to determine. The only use that can be made of them is first to use the true quantities, in order to get the parallaxes and apparent values approximately, and then to repeat the operation. To avoid this difficulty, substitute in the former ft + A ft instead of ft', and in the latter put D A D instead of D' and we get, by expansion, sin A ft = - (sin ft cos A ft -f cos ft sin A ft) sin AD rr^sinP cos AD jsin/ cosD cos/ sinD COB (* + **&) 1 I cos i A ft J + f sin P sin A D \ sin / sin D + cos / cos D . * . > I cos ^ A ft J Divide these by cos Aft, cos AD, respectively, and solve for tan Aft and tan AD, and we find tan Aft == tan A D = p cos / sin P \ 1 Sin ft cos D J / P cos / sin P \ 1 cos ft \ cos D J f sin P | sin / cos D cos / sii (3) cos(ft + _Aft) cos 4 A ft . -r, ( . . COS (ft+ T Aft) 1 f sm P < sm / sm D + cos / cos D r, tanD (P sin / sm P) cos D \ 1 tan/ cos i A/i (/J + TA/0 COS i A ^ I 1 + tan/tanD cos (ft + A ft) cos T A ft (4) These expressions are all of them perfectly rigorous, and better suited to calcu- lation than they would appear at first sight. The process of the calculation, in which five places of figures will be sufficient, is more detailed in the following equations : (/>cos/) sinP cosD n sin h tanA/i= j- 1 n cos/4 h 2 104 On Ecli c =r (y sin /) sin P \\ k tanD n. 2 = cos A h _k__ tan D c cos D (1 n t ) 1 c sin D ( 1 tan A D The expression (4) for tan A D may, however, be neatly resolved by spherical triangle as follows : Assume cos (h + i A/0 (6) means of a cos (A) = cos -j A h (a) (/O being very nearly equal to h + T A A. And let N be the North Pole, Z the central zenith, and M the Moon; then NM = 90 D, NZ = 90 / and the Z N = h. Without changing these values of NM, N Z, let us suppose the hour angle N to become increased to the value of (/O; and with the triangle so constituted suppose the altitude of the Moon to be , so that Z M = 90 e then the spherical relations sin ZM cos M = cos NZ sin NM sin NZ cos NM cos N cosZM = cosNZ cosNM + sinNZ sinNM cosN gve cos cos M = sin / cos D cos / sin D cos (A) . = sin / cos D cos / sm D cos $ A ft sin c = sin / sin D + cos / cos D cos (A) cos A + _ = sin / sm D 4- cos / cos D cos k A h Comparing these with the former expression of (4) we have therefore _ cos M ..... _ (p sin P) cos e tan A D = t r , . '^ 1 (^sin P) sm Before this can be used the angles M and must be determined. Draw ZD perpendicular -to MN, and by spherics, tanND = tanNZcosN sin MD tan M = tan ZD sin N D tan N sin ND . * . tan M = - - tanN Also by (c) sinMD tanMZ ~ l ,- , or cot MZ = cot MDcosM - cos M sin ND BinMD tan 1\I cos N sin M cos N sin NZ (d) tanN cos M sin N cos M sin MZ On Eclipses 105 Let now ND = 0, and MD = MN e = 90 (0 + D) ; and the equations 0> (ft)? ( c )> ( ( 0> ( {> )> (/)) will give the following cos (A + A A) f , cos A A tan r cot / cos (A) tanM= ^7?TD) tail(/ ' tan rr tan (0 + D) cos M sin cos (A) cos / cos (0 + D) cos M cos c (p sin P) cos e tan A D = ^ --^ cos M 1 ( p sin P) sine in which the equation (e) is used as a check on the preceding compulations. This check affords a good security to the accuracy of the work, and gives to these equations a decided preference over those of (6), although a trifle more perhaps in point of calcu- lation. They have also another advantage, inasmuch as M may be considered as the parallactic angle and e the altitude of the Moon; the former of these is useful in deter- mining the position of the line joining the centres of the two bodies in relation to the vertical, and the other is useful in finding the augmentation of the Moon's semi- diameter, which we shall now consider. If s' denote the Moon's apparent semidiameter, and s her true semidiameter as seen from the centre of the Earth, the actual semidiameter of the Moon will be represented by both r sin s and r' sin s' ; also, if a perpendicular be drawn from the centre of the Moon upon the radius f produced, this perpendicular will be represented by both r sin Z and r 1 sin Z'. We must therefore have - = sin s sin L Let M be the true position of the Moon, in the preceding figure, and sin ZM sin ZNZM = sin NM sin N will be sin Z sin ZNZM ~ cos D sin A; for the apparent position of the Moon the angle NZM will remain the same, and sin Z' sin ZNZM = cos D 1 sin h'. sin Z' cos D' sin A' sin Z cos D sin A Also, by means of the equations (8), (9), page 53, sin Z' _ p sin P sin Z' sin z cos z cos 2 sin Z p sin P sin Z p sin P sin Z p sin P sin Z 1 p sin P cos Z sin s f sin Z ; cos D 7 sin h 1 cos z , . sin s sin Z cos D sin A ' " 1 p sin P cos Z All the preceding formulae are strict in theory. It now remains to consider what allowances may be made and what facilities given in their actual calculation. In the first place the value of cos 1 A A may be safely assumed equal to unity, and may therefore be rejected in the equations (2), (4), (6), and (7), so that (A) = A + ^ A A : it may be shown that this supposition cannot involve an error of more than 0" '03 in the value of A D. 106 On Eclipses. Also, as the arcs P, A A, AD are small, we must have very nearly an A h tan A D AD = tan 1" = [4 -68557], where P, A /t, A D, denote respectively the numbers of seconds they contain. These equations may be made more exact, for the limits between which the angles are always com- prised, by adopting numbers differing a little from sin \" and tan 1"; thus, by assuming sin P = [4 '68555] tan A h = [4 -68561] P A h The first supposition will not in any case involve an error exceeding that of 0" *05 in the value of P, nor the second an error of more than 0" *1 in the value of A/I, and these are much too small to merit attention ; the latter assumption applies equally the same to AD. Thus we shall have (/i) = h -f i A/t, sin P r [4 '68555] P, A h = [5 '31439] tan A h t A D = [5 '31439] tan A D ; also A h = A or, the parallax in right ascension. The equations (3) and (7) may therefore be commodiously arranged as follows: c==[4'68555]/> m = A cos cosD n = k cos h (9) In By taking h less than 180, positively or negatively, A will have the same sign as h. (/i) ~ h + ^ A oc G~ cos tan Q =r cos (A) cot I sin e B COS M COS n v = A sin tan(/i) cos I tan = tan (0 + D) cos M sin0 G check - - cos (0 + D) AD = [5 -31439] AB (10) The auxiliary arc may be taken out in the first quadrant, + or ; calling to 180 the first semicircle, and 180 to 360 or to 180 the second semicircle, the paral- lactic angle M must be taken out in the same semicircle with h ; and A D will have the same sign as cos M. It will appear by the preceding investigations that the values of A , A D, so deduced, are the quantities to be subtracted from the true values of A. R., D, to get the apparent. As the number n is always very small, the values of comp. log. ( 1 n) to the fifth place of figures may be comprised in the following useful Table under the title of Correction of Log. Parallax, and conveniently taken out with the nearest third figure of the argument. On Eclipses. 107 Correction of Log. Parallax. Argument : log. n. Log Corr. Log Corr. Logra Corr. Log n Corr. Log n Corr. 5 '00 7 'ioo 54 7 '400 109 7-/00 218 8 -000 436 10 no 55 410 112 710 223 010 447 20 1 120 57 420 114 720 229 020 457 30 1 130 58 430 117 730 234 030 468 40 1 140 60 440 120 740 240 040 479 50 1 150 6l 450 123 '750 245 050 490 60 2 160 63 460 125 760 251 060 501 70 2 170 64 470 128 770 257 070 513 80 2 180 66 480 131 780 263 080 525 90 3 190 68 490 134 790 269 090 537 6 '00 4 200 69 500 137 800 275 100 550 10 6 210 71 510 141 810 281 110 563 20 7 220 72 520 144 820 288 120 576 30 9 230 74 530 148 830 294 130 590 40 ll 240 76 540 151 840 302 140 604 50 14 250 77 550 155 850 308 150 618 60 17 260 79 560 158 860 315 160 632 70 22 270 81 570 162 870 323 170 647 80 27 280 83 580 165 880 331 180 663 90 34 290 85 590 169 890 338 190 678 7 4 oo 43 300 87 600 173 900 346 200 694 7 *ooo 43 310 89 610 177 910 355 210 710 010 44 320 91 620 181 *920 363 220 727 020 46 330 93 630 186 '930 371 230 744 030 47 340 95 640 191 940 379 240 761 040 48 350 98 650 195 950 388 250 779 050 49 360 100 660 199 960 398 8 -260 798 060 50 370 102 670 204 970 407 070 51 380 104 680 209 980 417 080 52 390 107 690 213 7 '990 427 090 53 7 '400 109 7-700 218 8 '000 436 7*100 54 This correction is additive when n is positive, and subtractive when n is negative. For the parallax in declination it will always be additive if the Moon be above the horizon. For the augmentation of the Moon's semidiameter we may assume cos z = I and Z = 90 e, so that _ _ 1 _ l s I f sin P sin e 1 n^ n t being the number which enters into the computation of A D. Hence s _ [9 -43537] P s ~ 1 w, 171, - - - - (11) 108 On Eclipses. This and tlie last formulae, for A c*, A D, entirely preclude tlie necessity of Laving' recourse to a table of the sines and tangents of small arcs, and possess much unifor- mity and simplicity in their application. To get the relative parallax of the Moon with respect to the Sun, we must use P IT, instead of P. If, therefore, P' denote the value of j> (P TT), or the relative horizontal parallax reduced to the latitude of the place, we must use sin P', instead of p sin P, in the preceding formulae. The determination of the apparent relative positions of the centres of the two bodies, as well as the augmentation of the semidiameter of the Moon, at any time, has now been reduced to a practical and expeditious set of formulae. A series of these apparent positions of the Moon, with respect to that of the Sun, will trace out her apparent relative orbit; and the contact of limbs will evidently take place when the apparent distance of the centres becomes equal to the sum or difference of the semi- diameter of the Sun and the augmented semidiameter of the Moon. For a distance equal to the sum of these semidiameters we shall have partial beginning or ending ; for a distance equal to their difference we shall have { annu/ar } be S innin g or ^ing, when s' {>} a Since the hour angle of the bodies is subject to the rapid variation of nearly 15 per hour, the effect produced by parallax will be of so irregular a nature as to give a decided curvature to the apparent relative orbit of the Moon. This curvature will be more strongly characterized when the eclipse takes place at some distance from the meridian or near to tbe horizon ; and the apparent relative hourly motion of the Moon, even during the short interval of the duration of the eclipse, will, through the same irregular influence, experience considerable variation. These circumstances will, in some measure, vitiate any results deduced in the usual manner, by supposing the portion of the orbit described, during the eclipse, to be a straight line, and using the relative motion, at the time of apparent conjunction, as a uniform quantity. The method we are about to pursue is very simple, and consists in assuming any time within the eclipse, and computing for this time the relative positions and motion of the bodies, and thence finding, without any reference whatever, either to the time of the middle of the eclipse, or to the time of conjunction, the times of beginning, greatest phase and ending, and the relative positions of the bodies at these times. The nearer the assumed time is to the time of the greatest phase, the more accurately will the time of that phase be determined ; and, similarly, the nearer that time is to the time of beginning or ending, the more certainty will attach to the determination. To find the apparent relative motion of the Moon, we must first determine the vari- ation which takes in the parallax. For this, take the equations (2), page 103, viz.: , sin P 7 cos/ . sin A = sin A h = sin h 1 ccsD Bin A D = sin P' { sin I cos D' - cos / sin D' cos ( ; * + I cos^ A or, substituting small arcs instead of their sines, A , = p,2ll s ; n/l < cos D AD = F j sin / COB D< - cos / sin D' 2iii^^il \ cos * A h On Eclipses'. 109 Since a portion of the apparent disc of the Moon is projected on that of the Sun, the apparent declination D' can differ very little from c. As the hourly variations of these small quantities are only required approximately, we may therefore use 5 instead of D', and neglect A /t, so as to have / cos / A a = P' - = sin h cosD A D ~ P' (sin I cos 5 cos / sin cos A) which expressions, though rough values of A , A D, will give their hourly vari- ations pretty accurately. For these, observing that h is the only quantity which, by its rapid variation, has any sensible influence on these values, we have by differen- tiation d ( A ) / _,. d/i . . A cos -V dt dt But by the equations (9) m [4 '68555] P'cos/ n = [4 '68555] P' =r cos/i L cos D Substitute, therefore, cosD P'cos/ =[5 '3 1445] 7?i and we get rf(AD) dt = [5 -3 1445] (-^ sin I'M m sin c^ sin If we adopt 14 29 7 as a mean value of-y, we shall have -j- sin 1" = [9 "40274], and [5 '31445]( ^ sin 1" J [4 71719] or [4 7172]. Therefore, if (5), the value of the Sun's decimation at the time of the middle of the eclipse, be adopted in the value of j - -, we may form the constants = [4 7172] 1 and then, using A ,, A D! in place of C , -- , we shall have A* =Q l n AD 1 = Q 2 si which offer a simple calculation. 110 On Eclipses. Let now, at any assumed time within the duration of the eclipse, S and M be the apparent positions of the centres of the Sun and Moon ; and B M E an arc of a great circle coin- ciding with the relative direction of the Moon's motion at that time, which arc we shall first adopt in place of the curvilinear orbit actually described. On the circle of declination, S N, demit the great circle perpendicular M d, and suppose B and E to be the positions of the Moon at the respective times of partial beginning and ending of the eclipse, and n the middle point. Assume SB = SE = ,$ / -j- is the apparent difference of the right ascensions of the bodies, and that D' D A D, is the apparent declina- tion of the Moon ; and that x = { D' + ( A a) corr. } y = { A } cos D' and consequently also a; 1 =D 1 ~AD 1 cos D' (H) (15) Moreover, the figure occupying so small a portion of the sphere, and being com- posed of arcs of great circles, we may, without any appreciable error, treat these arcs as straight lines ; thence we shall obviously have a; cot i = sin S cos S Hourly motion in the orbit = cos i 71= Wcos(S + Again, in the triangles B S M, E S M, - - - (16) and consequently, by plane trigonometry, 112 On Eclipses. 0} EM = COS (U COS W With the above hourly motion in the orbit we shall therefore have Time of describing BM = ZUL* s in { ,, + (S + ) } ?/! cos o> W cos e . n M = sin ( S + i) W cos t EM =r sm { w (S + t) } ?/, COS W Let now, t 2 be corrections to be applied to the time assumed to get the times of beginning and ending, and (0 the correction for the time of the greatest phase. Then we have evidently {*i ] [ BM ] f negative 1 (t) \ = the time of describing i n M > with a < negative [sign. e,J I EM J [ positive J To have these times expressed in seconds, assume c = Wcos ' x 36oo _ w cos ' . t yi cos a> 7/j cos and then we shall derive /j = csm { (S-f ">} * g :=csiii { (S + t) + *>} (/) =r ccos w sin { (S + t)} and hence {beginning j f c sin { (S + t) w} 1 greatest phase > = Assumed time + \ ccoswslnf (S + t)} >-(18) ending [ csin { (S + + a '} J It has been observed, that any one of these values will be the more to be depended on the more nearly it approximates to the assumed time. Thus, if the assumed time be within ten minutes or so of the end of the eclipse, the point M will approximate so closely to the point E, that no sensible error can arise by supposing the small portion M E of the orbit to be a straight line, and to be passed over by the Moon with an uniform motion. This circumstance renders it advisable, in the first instance, to take the assumed time near to the time of the middle of the eclipse, so as to give, a good result for the time of the greatest phase, and results for the times of beginning and ending, which may be nearly equally relied on. Such a computation will be suf- ficiently exact for the usual purposes of prediction. When the time of beginning or ending is wanted to great minuteness to compare with observation, it will only be necessary to repeat the operation for a time assumed as near as convenient to the first determination, which will mostly give within a fractional part of a second of the true theoretical result ; a degree of accuracy, however, seldom wished for, and quite unsup- ported by the present state of the lunar theory. To fix on a time near to the middle of the eclipse for the radical computation, one of the most simple expedients will be to determine roughly the time of the apparent conjunction. On Eclipses. 1 13 We shall now briefly consider the apparent positions of the Moon, as related to the Sun's centre. It is clear that S is the angle of position of the Moon's centre from the North towards the East, at the time assumed ; also, that the angle N S B = to + t is the similar angle of position from the North towards the West at the time of begin- ning j and that the angle N S E = w i is the angle of position from the North towards the East at the time of ending; and that the angle N Sn = t is the same angle towards the West at the time of the greatest phase. Therefore, by estimating all these angles towards the East we shall have {beginning | f ( _ 4 ) _ w J greatest phase > Z of 3) 's centre from N. towards E. = |( _ t ) [-(19) ending j (( _ t ) + w J In the computation of the parallax in declination we find an angle M, which in practice may be supposed to be the angle N S Z for the assumed time, the zenith Z being reckoned towards the East ; consequently, at this time we shall have S M for the angle of position of the Moon's centre from the Zenith towards the East. At any other time the parallactic angle M for the latitude of Greenwich may be taken from the following table, arguments the corresponding apparent time and the Sun's decli- nation. This table, for any other place, may be computed by formulae, such as at page 105, viz. tan = cot / cos h tan M = 7^ r N tan h cos(0+c>) h being the angle answering to the apparent time. Those who may be engaged in the computation of Eclipses, for any particular places, \vill find considerable facility in the formation of similar tables. For an Occultation of a Star by the Moon the argument, instead of the apparent time, will be the star's hour angle, or the sidereal time minus the star's right ascen- sion. In this case the required positions will be those of the star with respect to the Moon's centre, which will therefore be different from the angles of position for a solar eclipse, in which the Moon's centre is referred to that of the Sun. The angular posi- tions of the contacts at immersion arid emersion will consequently be determined in the same way as for an eclipse of the Sun, and will be estimated in the opposite direc- tions. Thus, for an Occultation, A . f immersion 1 , ~ , f XT . , -r, f(180 t ) w} At 1 emersion } Z of * from N " towards E ' {(!*- ,) + .) And so must 180 be applied to the other angles of position, as expressed for a solar eclipse : this will make the expressions for the direct images of occultations the same as those for the inverted images of eclipses of the Sun, in estimating the contacts either from the north point or from the vertex. 114 On Eclipses. Parallactic Angles for the Latitude of Greenwich. {same sign as 7i) Arguments: Apparent Hour Angle and Declination. Dec. Hour Angle h. North. o o o o o o o o o 10 20 30 40 50 60 70 80 90 100 110 120 130 140 o o o o o o o o o o o o o o 8 15 22 27 31 35 37 38 39 38 37 35 31 27 1 8 15 22 27 32 35 37 38 39 38 37 34 31 27 2 8 16 22 28 32 35 37 38 39 38 37 34 31 27 3 a 16 22 28 32 35 37 38 39 38 36 34 31 26 4 8 16 23 28 32 35 37 38 39 38 36 34 31 26 5 9 16 23 28 33 36 38 39 39 38 36 34 30 26 6 9 17 23 29 33 36 38 39 39 38 36 34 30 26 7 9 17 24 29 33 36 38 39 39 38 36 34 30 26 8 9 17 24 29 34 36 38 39 39 38 36 33 30 25 9 9 17 24 30 34 37 38 39 39 38 36 33 30 25 10 9 18 25 30 34 37 39 39 39 38 36 33 30 25 11 9 18 25 31 35 37 39 39 39 38 36 33 29 25 12 10 18 25 31 35 38 39 40 39 38 36 33 29 25 13 10 19 26 31 35 38 39 40 39 38 36 33 29 25 14 10 19 26 32 36 38 40 40 39 38 36 33 29 25. 15 . 10 19 27 32 36 39 40 40 39 38 36 33 29 24 16 n 20 27 32 37 39 40 40 40 38 36 33 29 24 17 11 20 28 33 37 39 40 41 40 38 36 33 29 24 18 11 21 28 34 38 40 41 41 40 38 36 33 29 24 19 11 21 29 34 38 40 41 41 40 38 36 33 29 24 20 12 22 29 35 39 41 41 41 40 38 36 33 29 24 21 12 22 30 36 39 41 42 42 40 39 36 33 29 24 22 12 23 30 36 40 42 42 42 41 39 36 33 29 24 23 13 23 31 37 40 42 43 42 41 39 36 33 29 24 24 13 24 32 38 41 43 43 42 41 39 36 33 29 24 25 14 25 33 38 42 43 43 43 41 39 36 33 29 24 26 14 26 34 39 42 44 44 43 42 39 36 33 29 24 27 14 26 35 40 43 44 44 43 42 39 36 33 29 24 28 15 27 35 41 43 45 45 44 42 40 37 33 29 24 29 16 28 36 41 44 45 45 44 42 40 37 33 29 24 By .subtracting the parallactic angle, for the respective times of beginning, greatest phase, and ending, from the foregoing angles of position of the Moon's centre from the North towards the East, we shall evidently obtain the same angles from the Zenith or Vertex towards the East. If, however, the operation be repeated for the accurate determination of the times of beginning and ending, we shall have in the calculations the angle M, also at these times. Let i l9 u^ M l be the angles appertaining to the beginning, and t s , u^ M 2 those for the ending, and we shall evidently have the following values, which will be more accurate than the preceding : On Eclipses. 115 Parallactic Angles for the Latitude of Greenwich. (same sign as /*) Arguments: Apparent Hour Angle and Declination. Hour Angle h. Dec. South. o o o o o o o o o a 10 20 30 40 50 60 70 80 90 100 110 120 130 140 o o o o o o o o 8 15 22 27 31 35 37 38 39 38 37 35 31 27 1 8 15 21 27 31 34 37 88 39 33 37 35 32 27 2 8 15 21 27 31 34 37 38 39 38 37 35 32 28 3 8 15 21 26 31 34 36 38 39 38 37 35 32 28 4 7 15 21 26 31 34 36 38 39 38 37 35 32 28 5 7 15 21 26 30 34 36 38 39 39 38 36 33 28 6 7 14 20 26 30 34 36 38 39 39 38 36 33 29' 7 7 14 20 26 30 34 36 38 39 39 38 36 33 29 8 7 14 20 25 30 33 36 38 39 39 38 36 34 29 9 7 14 20 25 30 33 36 38 39 39 38 37 34 30 10 7 14 20 25 30 33 36 38 .3.9 39 39 37 34 30 11 7 14 20 25 29 33 36 38 39 39 39 37 35 31 12 7 14 20 25 29 33 36 38 39 40 39 38 35 31 13 7 14 19 25 29 33 36 38 39 40 39 38 35 31 14 7 13 19 25 29 33 36 38 39 40 40 38 36 32 15 7 13 19 24 29 33 36 38 39 40 40 39 36 32, 16 7 13 19 24 29 33 36 38 40 40 40 39 37 32 17 7 13 19 24 29 33 36 38 40 41 40 39 37 33 18 7 13 19 24 29 33 36 38 40 41 41 40 38 34 19 7 13 19 24 29 33 36 38 40 41 41 40 38 34 20 7 13 19 24 29 33 36 38 40 41 41 41 39 35 21 6 13 19 24 29 33 36 39 40 -42 42 41 39 36 22 6 13 19 24 29 33 36 39 41 42 42 42 40 36 23 6 13 18 24 29 33 36 39 41 42 43 42 40 37 24 6 13 18 24 29 33 36 39 41 42 43 43 41 38 25 6 13 18 24 29 33 36 39 41 43 43 43 42 38 26 6 13 18 24 29 33 36 39 42 43 44 44 42 39 27 6 13 18 24 29 33 36 39 42 43 44 44 43 40 28 6 12 18 24 29 33 37 40 42 44 45 45 43 41 29 6 12 18 24 29 33 37 40 42 44 45 45 44 41 f beginning For < greatest phase ending Z of }) 's centre fromN. towards E. = Z of 3) 's centre from Vertex towards E f (-O-^-Mn .=](-0-M [- I ( ') + "a M'J (20) These angles relate to the natural appearance or direct images of the bodies. For the same angles, as they will appear through an inverting telescope, + 180 must be applied : this may be simply done by using (180 t) instead of ( i). 116 On Eclipses. To find the time when the apparent conjunction takes place, let t denote the interval, in units of an hour, to be applied to the time of the true conjunction, and h the com- mon hour angle of the bodies at the true conjunction. Then the position of the Sun not being supposed to be influenced by parallax, the common apparent hour angle of the bodies, at the time of the apparent conjunction, will be h' = h-\- 15 . t ; and therefore, at this time, = l t A a = (P 1 ^^] sin (A + 15 . so that the condition for apparent conjunction, viz. ' rr A = 0, gives M (V ~ N U n '( / *- M5 - o = ( 21 ) \ cosD j for the determination of the interval t which from this equation will be best found, perhaps, by the usual method of double position. We only want, however, an approxi- mate value, and may therefore avoid much unnecessary labour in estimating this time. Thus, at the time of true conjunction, the same approximate formulae may be adopted as used at page 109, viz : _.. cos/ . A P' sin h cosD .. / dh , A cos / A != F -r- sin 1" ) cos h \ dt J cos D in which applies to the Moon. It is evident then, as the true positions of the bodies have no difference of right ascension, that A is the apparent difference of right ascension ; and consequently, as the relative apparent motion in right ascension is ! Ai or l P'( sin I'M ^ - cos/t, the correction t to be applied to \ dt J cos D the time of true conjunction to get that of the apparent, will be . cos/ P' -=r- sm h . . cosD sm/t D/ / dh . A cos/ cosD / dh . A P' r- sm 1" cos h oil -=rj r 17 sm * cos h \dt J cosD P'cos/ \ Make now the following assumptions : (D + a'corr.) S a cos D' p = j cos i sii \ * - - (4) ; corr.) } sin i H a cos D' cos t AD A a cos D' . > = r cost smt k k Jfr (5) k k A q = j- A D sin t -J A a cos D ; cos t and, observing the above values of x and y, the equations (2), (3), will become rfrsT+fcsinw (g A?) ) NAUTICAL ALMANAC, 1836. APPENDIX. i 118 On Eclipses. Let 7, Y'j be determined by the equations and p, 9, will take the following values p =: Y CO s (y 4. t ) q r= &y sin (Y' + It yet remains to determine the values of Ap, A 1 ! COST A J To simplify the expressions, let _ [5 -31439] A cosD / (1 -n)A' cosD [5 -31439] A [5 -31439] A c 7 -**. cos D a = -7- sin D (1 wO A' (1 nC) A' and b A ' cos / sin h -^v~ AD = cA ; sin/ A ; cos / cos T A == c A ' sin / a A ' cos / cos h + a A ' tan cos / sin h These substituted in (5) give Ap = c cos i sin / cos / 1 a cos i cos h ( a cos t tan b sin t) sin /i 1 A 9 = Arc sin i sin / cos / ! ka sin t cos A (ka sin i tan j- 6 cos t) sin h > The value of b contains the factor , for which we have cosD cos D' = cos AD (1 + tan D tan AD) Substitute the first value of tan AD, page 103, and cosD' - = cos AD i of the fraction, cos D 1 p sin P {sin / sin D + cos / cos D cos (h) } Or, putting h instead of (A) in the numerator, which cannot sensibly affect the value cos D' 1 n =r- s= cos A D cosD 1 Wi On Eclipses. 119 This, supposing cos AD = 1, reduces the values of the constants a, 6, c, to the following, ~ [5-31439]A j (l-*i) A' V ..... (9) c = 6 cos D a = 6 sin D > If e be a small arc determined by g cose = 6, g sine = a tan, we shall have a cos i tan -- b sin i == # sin ( t + e) = cj cos (90 + t e) &a sin t tan - + kb cos L kg cos (t e) = kg sin (90 + t e) However, as e must always be a very small arc, we may suppose cos e = 1 ; also = p L 7 sin / + 7 r cos / cos (^'+X) 1 t-(T q) +^smw + L // sin/ 7" cos / cos (f ;/ + X) J After computing the constants k, p, g, L', L/ 7 , V'j Y'"* b Y rneans of the equations (1), (7)> ( 8 ) (9)> ( 10 ) (H)j (13), and (14), we shall thus have two numerical equations for the determination of w and the Greenwich time t of the phase, for any place whose latitude is / and longitude X. The accuracy of the determination will principally depend on the proximity of the resulting time t to the assumed time T ; and therefore the result will be near the truth for all places where the phase will take place near to this time. In making these calculations for any particular portion of country, which for the partial phase will be necessary for both the beginning and ending, it will be best in the first instance to fix upon a place near the centre and compute the eclipse for that place, which computation will furnish good mean values for the data D, , 5, ' corr., AD, A , t, y A', A, and comp. log (1 nj. i 2 120 On Eclipses. = 7" I = -L" i (16) By supposing 7 cos /' = 7 7 I" cos / /7 sr 7" ' sin /' = L 7 " sin /" the expressions L 7 sin / + 7 7 cos / cos (Y^ 7 +X) L 7/ sin / -f 7 /7 cos / cos (Y^' + X) will take the forms t! {sin /' sin / + cos I 1 cos / cos (y^ 7 + X) } /7 {sin I" sin / + cos I" cos / cos (f " + X) } and, without the factors ', 7/ , will represent the cosines of the distances of the pro- posed place from two other places whose latitudes are / 7 , l" t and west longitudes Y*', V"- The former of these two places will be near to the southern pole of the true relative orbit, and the latter will be near to the orbit itself, and will precede the Moon by a distance nearly equal to 90. For purposes, which do not require great minuteness, the preceding equations will admit of some simplification by neglecting the small angle e. Add the squares of the equations (13) and (14), observing that c 2 + 2 = fe 8 , and which give the general relation L" 8 7 /72 /v rt By neglecting e, \ ^ 9 + *> cos x ~ sin i, sin x = cos t ; and then /< = v (17) which united with the equations ( 16) give ' = b, %' ^kb, and hence Or, C COS t 'l ri b 7' = ' cos l'~b cos /' = cos D cos t sin t = cos D sin i 7" = " cos l"~kb cos /" ,"-m= * is "' x = COS I COS L k b cos/ 77 cos/ 77 sin /' = cos D cos i L 7 = -6 sin/' 7':= 6 cos/' n' H) = sin D cos i b l sin (V' H) = shit (20) 7-r- ^ cos D sin t kb -^-cos(V" H) = sinDsint l ----- -- (21) ^-BinCV" H) = cost in which the coefficients c, a, will not be required. III. TRANSITS OF MERCURY AND VENUS OVER THE Disc OF THE SUN. These phenomena are, in many respects, analogous to that of an annular eclipse of the Sun, and admit of a similar calculation; the principal distinction consists in the negative sign of the relative motion of the Planet in right ascension, which will make the inclination of the orbit always obtuse, and therefore render some modifications necessary in the determination of the particular species of the other angles which enter into the computation. To avoid any confusion that might thus arise, we shall adopt the Sun as the moveable body, and refer his positions to that of the Planet which we now suppose to be stationary. Thus, S = the 0's declination. D = the planet's declination. it = the O 's equatorial horizontal parallax. P = the planet's equatorial horizontal parallax. = the J s right ascension minus that of the planet. x = ($' + a'corr.) D. y = ' COS y. Xi = the 's motion in declination minus that of the planet. y l = (0's motion in right ascension minus that of planet) -cos $', and so we might proceed as with an eclipse of the Sun, only observing that the rela- tive parallax p (IT P) is a negative quantity, and that the positions of the contacts on the limb of the Sun, as in the case of an occultation, will be at points opposite to those which come out in the calculation. However, as the relative parallax is always very small, the ingress and egress of the planet will be seen at all places on the earth at nearly the same absolute time ; it will, for this reason, be best to compute first the circumstances for the centre of the earth, and then to ascertain the small vari- ations produced by parallax for any assumed place on the surface, which may be readily deduced from the preceding equations for the reduction of an eclipse of the Sun. Let w, (), be the values of o>, t, for the centre of the earth, and, by separating the effects of parallax from the equations (6), 122 On Eclipses. cos w = p (0 = (T-?) + ft sin w A cos w = A p A / ~ A cos { ~ X + w } = sin { i + w } . We shall therefore have for the time of ingress or egress the following general expression, in which the terms within the brackets depend on the position of the place of obser- vation ; also the upper signs apply to the ingress, and the under signs to the egress. t = T q + k sin w cos{ i+w} . , / . k cos{ -i+w} , sin{ i + w} . \ sm h cos / sin w J kb sin/ ( sin 5 sm w v sin w cos/i Assuming k" = : , this expression will resolve into the following : psinw tan i = - k [3-55630] - y\ (^ + corr.) D 7 cos"^ cos^ cosw = 7 cos (^ -f ^ = *-/ sin (y + i) (0= T q + * sinw (a) (O A sin w L" = cos{( i) + w} l^-cosC^" H) = cos {( t) + w} sinS R, " p cos / cos W + X) L" /> sin / } On Eclipses. 123 In these equations H the O's true hour angle from the meridian of Greenwich, at the time () For I exterior 1 contact of limbs, A = { ' + '1 I interior J \ a s] For contact of centre of planet with O 's limb, A = a s denoting the true semidiameter of the Planet, and a that of the Sun. The equations (a), (5), (c), (d), will serve to determine the constants (), 7", L", ^", for the times of ingress and egress, and then there will result two numerical equations of the form (?) to reduce the phenomena to any place on the earth's surface. For the points on the limb of the Sun we shall have At { in S ress \ angle from N. towards E = |(180-0-w j for ^. I egress f I (180 0+wj "~^~ w > for inverted image; which will be sufficiently accurate for all places on the earth. The time T may be assumed near to the time of conjunction in longitude, or right ascension, as it may suit convenience. For Mercury, if very minute accuracy is wanted, it may be necessary, for more correct values of (0, to assume two times T near to the times of ingress and egress ; but it is very questionable whether such a precarious extent of accuracy would sufficiently recompense the time expended on the calculation. IV. OCCULT ATIONS OF STARS BY THE MOON. These may be calculated in the same manner as Eclipses of the Sun, the only differ- ence in the operation consisting in the star having neither motion, parallax, nor semi- diameter. But, where great minuteness is not wanted, these particular circumstances will afford some degree of simplification to the expressions, if that parallax of the Moon be adopted which would answer to the star as an apparent place, since this parallax, at the times of immersion and emersion, will then be precisely that of the respective points of the Moon's limb which come in contact with the star; and thus the augmen- tation of the Moon's semidiameter will be evaded, so that the true semidiameter may be employed. For this novel and judicious expedient we are indebted to Carlini. See Zach's Correspond ance, vol. xviii. page 528. As in the case of the Sun, let 3 denote the declination, and h the hour angle of the star ; and let P represent the equatorial horizontal parallax of the Moon. Then, for the effects of parallax in right ascension and declination, we must substitute S for D', and h for h 1 in the formulae (2) at page 103, which thus become, disregarding ^ A h, _ cos / A = p P sin h cosD A D = p P (sin / cos B cos / sin cos A) As soon as the immersion takes place, these expressions will represent the parallax of that point of the Moon's limb which is in contact with the star; and, therefore, the application of this parallax to the centre of the Moon will produce an apparent dis- tance A ', of the centres, equal to the true semidiameter s of the Moon. Also as the star, in the course of the occultation, is only affected with its apparent diurnal motion, the hourly variations of the above values will be 124 On Eclipses. fdh . ,\ cos / A , = p P sin 1" ) cos h \dt ) cos D A D! = p P ( -T- sin I'M cos / sin 5 sin h in which is 15 2' 28", the hourly diurnal motion of the Earth, and therefore gsinl"=[9-419l6]. Assume , rn cos U ' = p cos / =r (1) which are constant coefficients depending on the latitude of the place ; then 00). p 0(3). p A = sin h A j = = cos A cos D cos D A D = (0 (2J cos 2 C1) sin cos A ) . P A D! = (3) . P sin 3 sin h If, in the values of A, Ai, we use cos instead of cos D, the values of #, y, a'^y^ page 111, will become x = (D 3) (0 (2) . P cos S (1) . P sin 3 cos A) y r a cos 3 (1) . P sin h > XON arj = D! (3) . P sin 5 sin h y t = ai COS 5 (3) . P COS h in which we have disregarded the correction. With the values of x 9 y, x lt y,, so found, we may then proceed with the equations (16) and (18), pages 111 and 112, as in the case of a Solar Eclipse. This method is similar, and, as far as accuracy goes, the same as the recent method of Professor Bessel, who divides all the quantities by the equatorial horizontal parallax of the Moon, He assumes ot. cos B #i cos 0* - *rv *^^ P " ~~p P p L P u = (l) sin h u 1 = (3) cos h v = (2) cos ^ (1) sin ^ cos h v 1 = (3) sin 5 sin h so that if we change the signification of the symbols or, y, ari, y t , and suppose them now to represent the preceding values divided by P, we shall have x = q v x l z=. q 1 v 1 1 , . s y = p M y l ^=p l u' ) These values being adopted, in proceeding with the equations (16) and (18) we must use A ' = -^-, the value of which, according to Burckhardt's Tables de la Lunc, (Paris, 181.2), page 73, is [9'43537]. Much facility is thus given to the calculation ' sin Z = sin sin w - - - - (8) because the squares of these three equations added together will give unity on each side. By these equations we shall hence have sin D' cos Z = sin D' cos sin w sin Z cos M sin Z (cos i cos ta 1 -f- sin t sin w') == (cos a-' sin Z) cos t + (sin w' sin Z) sin t ES cos i cos w + sin i sin sin w and consequently sin / =r cos D' cos i cos w + sin w (sin D' cos + cos D' sin i sin 0) which now involves only one variable 0. Again, assume two arcs 0, y, which will fulfil the equations cos cos y =: sin D' ...... (9) cos sin y = + cos D 7 sin i - - - (10) A third equation will follow from these, viz. sin 6 r cos D' cost ------(11) because, as before, the squares of these three equations will together make unity. The value of sin / will now become sin / cos w sin + sin w cos cos (0 -f V) The angle + V being the only variable in this expression, it is evident that the greatest value of / will have + y =r 0, and the least + V = 180. Therefore, f greatest 1, r , f # + w 1 . r f northern 1 v ., I least f value of ' = { 6 - w } ' usm w for { southern } hmlt These would be the extreme latitudes for the appearance of the occultation if the Earth were a transparent body ; as this, however, is not the case, it will be necessary that the star should be above the horizon, a condition not included in the preceding equations. The zenith distance Z must not exceed 90, and therefore cos Z must necessarily be a positive quantity. By the equation (6), cos Z must have the same sign as cos0, and this must be the same as + cos "^ for northern limit, or cos ^ for southern limit, because in the former case + ^ = 0, and in the latter + V = 180. But, by (9), cos V must have the same sign as D'. Consequently For limit > cos Z has the same sou t > - D It is evident, therefore, that the extreme northern limit will have the star below the horizon and be excluded when D' is negative, and that for the same reason the southern limit will be excluded when D' is positive. Thus the only admissible extreme limit will be determined by the equations (12) using upper signs when D' is positive, and under signs when D 7 is negative. The other limit for the actual appearance of the occultation will evidently be one of On Eclipses. 127 the two places where the other limiting line meets the rising and setting limits, and will be determined by cos w t: sin / 2 == cos D' cos -j ( t) + w r - - - (13) using, as before, upper signs when D 7 is positive, and under signs when D' is negative. The equations (11), (12), (13), for convenience in determining the species of the angles, may be put in the following form, n-A 7 + n + A 7 cos w pi P/ sin 9 = cos D' cos t > - - (14) I, == Wl sin 4 = + cos D' cos (w a t) observing that w 1} w 2 , 0, and i, must here take the same sign as D'; also under } si S ns when These formulae are applicable to a solar eclipse. For an occultation of a star by the Moon, P'will be the Moon's horizontal parallax, and A' her semidiameter, which, as these limits are not wanted very accurately, may be regarded as true quantities ; also we may neglect u and so take instead of D 7 . Since t= [9'43537] = '2725, the formulae for an occultation will hence be tan i = COS cos = + "2725 n = (diff. dec.) cos i cos w 2 = + + -2725 sin = cos $ cos i l sin / 2 T cos cos (w 2 t) (15) in which we also give to the angles W! , w 2 , i, 0, the same sign as S, and use upper signs when S is positive, and under signs when 5 is negative. We may also observe, that, 1 . When 5 is North, / t is the most northern limit ; and when is South, l v is the most southern limit. 2. When Wi is imaginary, / t will be 90, and of the same name as J. In this case the occultation will be visible about the pole of the Earth which is presented to the star ; the visibility will extend beyond the extremity of the disc of the Earth as it would be seen from the star. 3. When w a is imaginary, / 2 will be the complement of S and of a different name from . In this case, if we consider the disc of the Earth as seen from the star, the visibility of the occultation will extend beyond that extremity of the disc which has the pole on the other side of it. After an occultation is computed for any particular place, if we deduct the star's right ascension from the sidereal times of immersion and emersion we shall get the hour angles of the star, + West, East. By comparing these hour angles with the semidiurnal arc of the star, we can distinctly ascertain the positions of the star with respect to the horizon. 128 On Eclipses. V. ECLIPSES OF THE MOON BY THE EARTH'S SHADOW. These may be also resolved in the same way as those of the Sun. The absolute positions of the Moon and Shadow being independent of the position of the spectator on the Earth, the determination of parallaxes will be here unnecessary, which much simplifies the calculation of these eclipses. The considerations requisite to be attended to, by way of distinction, are the following : Semidiameter of the Shadow -r (P' + IT A =c(P ?r) m = s = [9 -43537] P 3. Take out D, S, , D,, for the time T. h == sidereal time at place minus }) ' s right ascension, to the tenth of a minute, in arc. m n = k cos h cos D A = [5 -31439] k sin h [corr. for n\ A ! = Qi n A D! = Q 2 sin /t Correction for w to be taken from the table on page 107 4, tan = cos (/t) cot / tan M = - _____ tan (A) cos check - - G = cos (h) cos / tan e = tan (0 + D) cos M B = cos M cos e sin G ~ 5" cos (0+D) M to be in the same semicircle with h On Eclipses. 131 A sine AD =r [5 '31439] A B [corr. forw,] s' r= s [corr. for w J Correction for rii to be taken from the table on page 107 5. D'~D AD y = ( A a) COS D' y t = ( ai A i) COS D' or = (D' + a'corr.) S x v = D t A D! = Wcosj sin S cos S _ W cos t [3 -55630] 7. n H cos w = c = A cos = c sn a t == c sn Time of greatest phase = sum of times of beginning and ending When n < s 1 132 On Eclipses. 9. FOR A MORE ACCURATE CALCULATION OF THE TlME, &C., OF BEGINNING OF THE PARTIAL PHASE, assume a convenient time near to the preceding determination. For this time, take out the quantities D, D M , , oc l9 from the Ephemeris; and pro- ceed as in Nos. 3, 4, 5, 6, 7, omitting 6, 2) and the times of greatest phase and ending. Let MI, ( tt>u be the values of the angles in this computation , then, for the posi- tion of the point of contact on the limb of the Sun, Angle from iy^ j towards the East = i/Z^Z^M } for direct ima S e< Angle from towards the East = fiJi; for inverted image. 10. FOR A MORE ACCURATE CALCULATION OF THE TlME, &C., OF ENDING OF THE PARTIAL PHASE, assume a convenient time near to the first determination. For this time, take out the values of D, U^ , , t ; and proceed as in Nos. 3,4, 5, 6, 7> omitting a, t it and the times of beginning and greatest phase. Let M a , t 2 , w 2 , be the angles in this computation; then, for the position of the point of contact on the limb of the Sun, Angle from {y^} towards the East = j [~^ + ^_ M J for direct imag6 ' Angle from j^J towards the East = { [jjfc fc iiwerted i II. FORMULA FOR REDUCTION TO DIFFERENT PLACES. 11. Instead of Nos. 5, 6, 7> substitute the following : D 7 = D AD ' = A y l =(i A0 cosD 7 tant = k =r [3'55630] 2/1 i (D + 7 corr.) a cos D p r= 7 cos (V^ + 7 ^ 7 sin (^ + t) T q = T 7 12. , [5-31439] A 6 = j [corr. for Hj A e m minutes = [7-9208] A sin D v = (90 + e 13. H =5 the true Greenwich hour angle of }) at the time T L 7 L 7/ r= cos D cos i -yy- := cos D sin i b kb yl ylt -7- COS (y'~ H) rr: sill D COS 4 -rT- COS ($" H) = Sill D Sill o kb yl yfl -j- sin (^' H) = cos x -rr- sin (^ 7/ H) = sin x On Eclipses. 133 14. The constants T 7 , k, p, L 7 , L/ 7 , 7 7 , 7", being so computed, the angle w and the time t of the phase for any place whose North latitude is / and East longitude X, will be determined by the two following equations, in which the upper sign relates to the beginning and the under sign to the ending. cos a? = p L 7 sin / -r- 7' cos / cos (X -f y 7 ) t = T 7 + k sin w + L" sin / 7 7/ cos / cos (X + y 77 ) The result will be the most accurate when the place is near to that on which the previous part of the calculation is founded. III. TRANSIT OF MERCURY OR VENUS OVER THE DISC OF THE SUN. (Same notation for the Planet as for the Moon.) 1 5. Assume the time T near to the time of conjunction in longitude, or right ascension, = Sun's right ascension Planet's right ascension in arc KI =r hourly variation of D!= Sun's hourly motion in declination minus that of the Planet For contact of Planet's centre with Sun's limb, A = a D, tan i = k r= [3-55630] 7 cos y = - cos 3 A cos i _ cos S corr.) D A cos w = 7 cos (V + q =z ky sin (^ + t) 16. H = the true Greenwich hour angle of at the time T kb sinw L 7/ = cosS cos {( c) + w} y" -jji cos (y 77 H) = sinS cos {( i) + w} ^ 8 i n(v ,//_H)=sm{(-0 T w 17. Then, for the centre of the earth, (0 = (T 9) + k sin w and, for any place whose latitude is / and east longitude X, *=(*) + {7" p cos / cos (\ + y") L 77 p sin /} using the upper signs for the ingress, and the under signs for the egress. The positions of the points of ingress and egress, estimated from the North point of the Sun's limb towards the East, as the transit would be seen from the centre of the earth, will be determined in the same manner as for the immersion and emersion of an Occultation, No. 19, using w for w. These angles may be assumed to be the same for any place on the surface, the effect of parallax being so very minute. NAUTICAL ALMANAC 1836. APPENDIX, 134 On Eclipses. IV. OCCULT ATI ON OF A STAR BY THE MOON. GENERAL LIMITS OF LATITUDE. 18. (! and D x at true 6 ) D t tan i = n = (diff. dec.) cos t ! COS cos Wi = + ~ -2*125 cosw 2 = + ~ + -2725 sin 9 = cos cos t A = Wj B sin / 2 = + cos 5 cos (w 2 t) w i> w 2 , t, 0, same sign as I u PP er 1 signs when is \ P osit ; ve 1 \ under j \ negative J When w t is impossible, l^ = 90, with the same name as $. When w 2 is impossible, / a = complement of , with different name from CALCULATION FOR PARTICULAR PLACE. 19. For the latitude of the place prepare the constants M 0( 3) = [9 -41916] (U cot / which will serve for all Occultations at that place. For the time of true <^ find h = sidereal time at place right ascension of Star and thence determine the time T, as in No. 1. For this time take out the quantities P, s, D, D!, a, i ; and compute x = (D S) (0 ( ^.Pcosa (1) . P sin S cos A) y = cos ^ (1) P sin A y. = ai COS 2 . P COS A, With these proceed as in Nos. 6 and 7, using A' = * = [9 "43537] P. 20. For the positions of the points of immersion and emersion on the limb of the Moon, At "on'' angle from North towards Jl for direct image. At {"SSJ 8 ari g lefromNorthtowardsEast = l(Zi)^w} for inverted ima 8 e ' For the same angles from the Vertex we must deduct the parallactic angle for each time. 2.1. If an accurate calculation is wanted, proceed as with a Solar Eclipse. On Eclipses. 135 V. ECLIPSE OF THE MOON. 22. Fix on a convenient time near to the time of opposition in longitude, or full moon; and for this time find P, s, TT, , AD t Partial A 7 - - - - 30 48 '3 Annular A'---- 051 '5 D + AD + I) o / // 19 33 43 35 26 + 23 49 A oc + 23 15 + 18 58 17 a' + 34 f + 22 1 ' corr. (log +1*53148 \ log + 3 '12090 185829 cos D'+ 9*97574 - - - +9-97574 7 f \ x - 12 y - + 1 -50/22 y l - + 3 '09664 (1) 138 On Eclipses, y - + 1 -50722 x - i -07918 4- HO 28 * t (tan S \cos S 9 ' 42804 y l - + 3-09664 (1) Xi - -f 2 '65514 cot i +0 '44150 54364 i + 19 53 '5 W - + 1 '53554 (S + t) 130 21 '5 - cos 9-81129 n 1 '34683 Partial - - log A ' 3 -26677 w + 9041-1 cos w 8 -08006 cos i +9 '97328 - - + 1 '53554 const. 3 -55630 + 5 '06512 (2) H + 1 '96848 (2) (1) - 8 '08006 -221 2'6 39 40 '4 c 3 -88842 sin a +9 '81732 c 3 '88842 sin b 9 '80510 PARTIAL. -(S+0 a b ANNULAR Assumed time Beginning - - Longitude - - Beginning - - n - - Annular - - log A' + 11533''-9 cos vo 130 21*5 c 3 70574 -f 3 -69352 h m s 1 24 39 3 13 - h m s t a + 1 22 18 3 13 1 48 21 12 44 Greenwich mean times, W. 12 44 W. 1 35 37 Edmburgh mean times. 1 -34683 1 '71181 H + 1 '96848 9 '63502 9 '63502 2 '33346 9 -96047 c 2 -33346 sin b 9-40711 245 55 '4 sin a + 14 47 -6 Assumed time Beginning Longitude . ."' Beginning 2 -29393 + 1 -74057 h m s h m s 3 17 t z + 55 3 13 3 13 3 9 43 12 44 Ending 3 13 55^' ( mean times. W. 12 44 W. 2 56 59 Ending 3 1 111 Edinbur g h & 1 mean times. POSITIONS OF CONTACTS FOR DIRECT IMAGE. (-0 -19'9 w +907 Partial contact at { J^J** ; ] _' * } f rora North towards j ^f (-0 - 19-9 u 4- 115 '6 Annular contact at ( be g hinin S { ending - from North towards West. East. On Eclipses. 139 For the same angles from Vertex we must estimate them towards the East, and deduct the angle M, thus Beginning 135 '5 M H-31'9 Ending + 95 '7 M +31-9 167'4 towards West. 63 '8 towards East. COMPUTATION FOR l h 48 m , FOR AN ACCURATE DETERMINATION OF PARTIAL BEGINNING. / // D + 19 19 35-9 a + D! + 9 26 Edinburgh Sid. Time at Greenwich f ill nm O 1 II 18 57 39-3 h m Mean Noon - - 3 20 1 15 23 '2 27 38 14-4 7-9 Sidereal Equivalei m _ - _ _ 7 '94712 cos D - - 9 '97481 k - - - - 7 -97231 cos h - - + 9*95707 it for 1 I 48 [ 48 }'s R.A. {time arc Const. - - 5 8 _______ 3 28 32 '2 18 '2 14 -0 i on;O 3' '5 2-1764 ~T &<* 5-31439 7 'Q7231 sin h - - - corr. for n - / J i "0 1 370 n - - - Qi log - - A !- - h (h) - : e - - - D + D - 7 '92938 47172 _l_ 2 'Ql 730 O \ A - - - - cos - - - - cot/ - - - - tane - - - - sin B - - "-'*-' - cos - - - - ~r * J L i u * - + 2 -6466 - + 13' 46"'6 flog - IAD, + 1 -8033 - + 7' 23" / - + 25 3'5 - + 6-9 - + 25 10 -4 / - + 31 36 '7 - + 19 19-6 - + 50 56 -3 + 1' 4" + 9 -95666 + 9-75001 + 9 -83256 cos / + 9 '78922 G + 970667 + 9*78665 + 971946 + 9 -79945 B tan (A) - - - o / [tan MI - - - + 9 '92001 - - check + 9 -67209 + 9-59210 - + 9 '92002 LCOS M 1 tan(0 + D) - + \) yoyi i - 09068 COSf - - - T + J 9 yuyn 81754 Q 05Q7Q B - - - - 4. () 78665 idii - cos sin - - - - - + - + 9 ( J 81754 87733 1 Q*7 1 1 const. - - 5 5 s 31439 10104 1Q71 1 . iy / 1 1 *-Jl L L 07444 corr for n \ 518 flog - - - 3 30333 IAD + 33 ' 30"-6 140 On Eclipses. log s - 2 -94904 518 {loo- - 0x400 -pv log - ? / i c n *n AD! - - s #! - - - D - - AD - / - +19 19 - + 33 // 35 30 '9 6 A 7 - - a A a 30 49 '9 15 23 -2 a, + + 13 46'6 A! + 27 38 7 23 ' corr. - + 18 46 - + 18 57 5 2 39 3 '2 3 | ' \log - cosD' 29 9 '8 + 3 '24299 log - + + 9 -97627 + 20 15 3 -08458 9 -97627 1 4 8 22 - - 11 31 '8 S ---- 112 39' '81- y - 3-21926 y t - + 3 '06085 (1) x - 2 '83998 x l - + 2 70070 (tan S + '37928 cot t t + '36015 ] - -T - Ism S 9-96510 cos tl +9*96215 --- + - 3 fi 3 -06085 A' 3-26715 90 + t - 1 13 34 '5 k + 3 -72475 6 + -24953 x - i 13 32 '2 D + ' corr. 6+3 '97428 o / // 19 19 35 -9 1 2'2 J cos D' + 2 9 96530 97627 & + 18 57 39'3 A 7 7 sin ^ 2 94157 . . A/ 3 "12018 _ i// ooO oo/.o J t an y 9 82139 T t + 23 34 *5 i cos y + 9 92092 A / V + l 9 57*7 A' A' i 3 19920 -26715 Q321 1 cos(V+0 + 9*99341 sin f' + O ~ 9 23802 {***" J |**& + 9 '92552 A; ""*'" 3 72475 p + '84240 -- 2 '89488 01 A + Loner. 25 3'-5 3 10 *9 W. * + 1 13 5 48 HP i . i o 1 K. cosD + 9*97481 cost + 9*96215 6 - - + -24953 cosx tan sin L' - - + -18649 sin D + 9*51977 cos t +9 -96215 + 9*48192 9 -60134 -11942 9-90109 r' H 5246 / -8{ t ? l*i H + 28 14 '4 +9 70025 6 - - -24953 y' . . 24 32 '4 - + 9 '94978 cosD + 9*97481 sin i +9 -60200 kb + 3-97428 H + 28 14-4 -j- 110 1-5 L" + 3 -55109 sin D + 9 '51977 sin t +9 -60200 sn sn + 9*12177 + 9 -96228 + -84051 + 9-99552 + 9-96676 kb - - 3 '97428 7" + 3-94104 142 On Eclipses. We have hence, for the Greenwich time t of beginning, at any place whose latitude is /, + North, South, and longitude X, + East, West, the two following equations, which may be safely depended on for any place in Scotland or the North of England. cosw = 0-84240 --[0-18649] sin / + [9'94978] cos/ cos (X 24 32''4) f2 h l m 5 s [372475] sin w+ [3-55109] sin/ [3-94104] cos/ cos (X+ 110 l'-5) Contact on 0's limb, w + 23 34' '5 from the North towards the West. As a check on this calculation take the assumed radical place, Edinburgh, and /=+5546 / '9, X = 3 10' '9, giving u = 89 6' '9 and* l h 45 m 24% which per- fectly coincide with the results of the original calculation. Similar calculations for the ending of the Eclipse give the equations, coso; = 0-93848 [0-20291] sin /-f [9-88677] cos/ cos (\+ 2/ 6'7) f == l h 38 m 33"+ [3-66890] sin w + [3-35544] sin/ [3'90073] cos / cos (X+ 153 3'-8) Contact on 0's limb, w 16 56' -2 from the North towards the East. Also by calculating with T 2=: 3 h 1 3 m for the annular phase there will result cos ct' = 29-66600 [175159] sin /+[ 1-46950] cos/ cos (X + 1 42'-4) *=l h 43 m 7 8 + [2-14475] sin u> + [3-45484] sin/ [3-92550] cos /cos (X+ 131 55'-9) Contact on 0's limb, 19 53' -5 + o> from the North towards the East, the upper sign appertaining to the beginning and the under sign to the ending. If cos tv > l the place will be without the limits, and the eclipse will not be annular. By taking /= +55 46''9, X= 3 10' '9, the results will exactly correspond with the special calculation. Note. The expression of cos u> for the annular phase, as the appearance of this phase is comprised within narrow limits on the surface of the Earth, will afford a very convenient and simple determination of the places which range in those limits as well as those which range in the central line ; and we may expect very accurate results throughout the portion of country originally taken into consideration. Thus for the Southern limit we must obviously have cos w = + 1 , for the Central line cos w =r 0, and for the Northern limit cos u> = 1 ; and hence the following conditions : {+ 1 ) f southern limit. > for < central eclipse. 1 J ( northern limit. By making the assumptions n 1 cos N' = 7' cos (X+VO I f \ + n'sinN'^L 7 j " they will give f p -f 1 1 [ southern limit 1 n 1 cos (N' + /) = < p > for < central eclipse ?----(*) ( p 1 J ( northern limit J If we therefore take any meridian whose East longitude is X, these two equations (r), (s) will serve to determine the extreme latitudes /, on this meridian, between which the eclipse will be annular as well as that where it will be central. For the preceding eclipse, these equations will be n 1 cos N' = [1 -46950] cos (X+ 1 42' '4) n' sinN 7 = [1 '75159] { [1 -45737] ] f southern limit. [1 -47226] V for < central eclipse. [1 '48665] J ( northern limit. On Eclipses. 143 If we take, for example, the meridian of Edinburgh, and use X 3 10''9, there will result, o / Extreme Southern Point of annular appearance, N. 54 19 *7 Point of Central appearance, N. 55 20 '4 Extreme Northern Point of annular appearance, N. 56 21 '7 which are geocentric latitudes. III. CALCULATION OF THE TRANSIT OF MERCURY, Nov. 7, 1835. The conjunction in right ascension takes place about 7 h 38 m ; take therefore T r= 7 h 40 m , an d we readily find from the ephemeris the following data, 5 16 15' 58" '2 O / // D 16 22 4 "2 D! 2 32 '6 s 4'8 * + 10 '95 v + 5 32'7 a 16 10 '4 TT 8-66 P 12 -66 With these quantities the calculation, for external contact of limbs, is as follows : P a 16 10-4 s 4'8 A 16 15 '2 // 12-66 8-66 4 -00 - - - - -60206 A 2 -98909 + 1 '03941 b + 7 "61297 i + 2 '52205 cos + 9 '98226 ...... +9 '98226 O f // $16 15 58 '2 corr. D 16 22 cos + 1 -02167 2) of COB) + 2-50431 4-2 acos$+ 1 -02167 D, 2- 32-6 - - 2-18355 + 2 '5.0431 6 6 -0 - - - - + 2 -56348 i t 25 32 '3 ' t f tan^ + 8 '45819 23 53-6 -0+9-96109 sin cosw +9 -53566 w + 6955'-4 cosf + 9*99982 + 2 -5636T A 2 -98909 , f tan 9 -67924 e qo .q 1 d \cos + 9-95535 A 2 '98909 const. 3 -55630 sinw +9 -97278 k + 3 -99643 7+9 ^7457 k + 3 -99643 9*60749 3 -17849 q O h 25 m 8 8 '3 T + 7_40 T + 8 5 8-3 + 6 -50074 k + 3 -99643 b + 7-61297 kb + 1 '60940 sin w + 9 ^7278 k" + 1 -63662 cos S + 9 '98226 k" cosS + 1 '61888 sinw +3-96921 - 2 35 15 Mean time of j 1 ^ 688 egress 10 40 23 -Q } for the centre of the Earth - 144 On Eclipses. CONSTANTS FOR REDUCTION OF INGRESS. Equa. -f | time -f (arc + - * + \v I W 5 29 52 7 16 10 -0 5 46 2*7 8630 / '7 25 32 '3 69 55 '4 44 23 'I Y<" H 105 58 '3 *" 19 27 -6 - - - - cos + 9 '85410 - - - - sin 9 '84477 sin 5 9 "44733 9 '30143 - 9 '30143 s$ + 1 '61888 L" + 1 -47298 f tan + { sin 9 '98290 + 9 '86187 k" + 1 -63662 7" + 1 -49841)" CONSTANTS FOR REDUCTION OF EGRESS. k m s 10 40 23 '9 Equa. + 16 9 -2 H in [time + 10 56 33 '1 (arc + 164 8'-3 * "{ 1 95 27 -7 88 28 -0 252 36-3 107 23 '7 - - - COS sin o 8 -9 '97854 44733 _ - _ _ sin + 9 99802 + 8 42587 . . . . -"V + 8 42587 { tan f 1 57215 \ sin + 9 '99984 k" cos $ + 1 61888 k" -** + 9 i '99818 63662 L" -59742 y" + 1 -63480 The former part of the calculation repeated for the times 5 h 30 m and 10 h 40 ra we shall find more accurate times of ingress and egress, for the centre of the earth, to be 5 h 29 m 56 s and 10 b 40 m 31% which however still cannot be depended on within a few seconds. More reliance can be placed in the amount of reduction for parallax. The times reduced for any place whose North latitude is /, and East longitude X, viz. : Ingress, Nov. 7 d 5 h 29 m 56 8 + [T4730] p sin/ [1'4985] /> cos /cos (X 19 28 7 ) Egress, - 10 40 31 + [G'5974] p sin/ + [1'6348] /> cos/ cos (X 107 24 ; ) will indicate, with considerable accuracy, the difference between the times at any two places. The positions of the contacts on the Sun's limb, for an inverted image, will be ; [ Jf ' } from the North towards the { Contact at On Eclipses. 145 IV. OCCULTATION OF A STAR. On January 7, 1836, the star t Leonis, whose right ascension is 10 h 23 m 26*'4 and declination N. 14 58' 39", will be Occulted by the Moon. LIMITS OF LATITUDE. At the time of true 6 in right ascension, viz. 12 h 12 m I) 8 , we have the following data, O I II I II D + 15 33 2 D! 11 47 $ + 14 58 39 ! + 30 41 P + 56 4 D 5 + 34 23 with which we proceed thus : D! 11 47'- - 2 '84942 cri + 30 41 - - +3 -26505 9 -58437 S + 14 59' cos + 9 '98498 (tan 9 -59939 i 21 41 < -, Icos + 9*96813 cliff. dec.+ 34' 23" h 3 '31450 n "T 5 " const. O / WL -f 147 24 - nat. cos 5699 2725 8424 2974 n + 3 '28263 P+56' 4"- -+ _ " + -5699 - - + 9 -75577 iv a + 107 18 - nat. cos L + 21 41 - log. cos -f 9'968T~(1) + 86 37' - log. cos + 8 -8833 (2) log. cos 5 + 9 '9850 (3) Q + 63 51 - log. cos + 9-9531 (l) + (3) /t + 83 33 4 14 / 2 4 14 log. sin / 2 + 8 -8683 (2)+ (3) The star may therefore be occulted between the parallels of latitude N. 83 33' and S.4 14'. The parallel of Greenwich is within these limits; and if the hour angle of the star be computed roughly for the meridian of Greenwich, the star will be found to be considerably elevated above the horizon. A special calculation for the Observatory of Greenwich will consequently serve as an example of the circumstances for a par- ticular place. CALCULATION FOR GREENWICH OBSERVATORY. Constants (1) , 0< f >, 0< 8) . P ---- cos/ 9-99913 9-79610 (l) +9 '79523 +9 '79523 cot/ + 9-90381 Const. - - 9 '41916 0W 1- 9-89142 (3) -f 9*21439 These will be constant for all Occupations at Greenwich. h in s Sidereal time at mean noon 19 4 22 '4 Star's right ascension - - - 10 23 26 '4 h at mean noon ----- 15 19 4 '0 -------- Mean time of true 6 - - - -f 12 12 T - - - - ;: - < + 2 4 -0 Acceleration h at true 6 h m 15 19 n 6 1 49-4 35 Acceleration - -f time 4 11 14 -6 arc - - 62 48'-7 -I With this and i = 30'- 7 we find, by the table ) at page 129,T = Il h 6 m . J h at mean noon is put down negatively, in order to have more readily the other values of h less than 12 1 ' or 180. 146 P 56' 4" - On J - + 3 -52686 + - + 9 '89142 cosh + Eclipses. 3-52686 9 '65983 sill h + 3*52686 -9-94915 cos a - - + 3 -41828 + - + 9 "98499 sin a + 3 -18669 9*41236 sinS 3 -47601 + 9*41236 r + 3-40327 + 2 -59905 2-88837 I + 42' 11" ?+ 9 '79523 ^ + 9 "21439 D-S - + 48 + + 38 3 - + 47 22 + Q JO 2 -39428 I *i - - 2' 7" 11 42 9 35 y *y f _ __ 33/ 54" fi - + 30' 44" t cos S - - P sin h - - 0w ... 3 '30835 - + 9 '98499 t 3 -29334 1 32' 45" - 3 -47601 P - - + 9 "79523 Const. cos a - ;:;: I 3-52686 P ( f s/l + 3 -26576 + 9 "98499 + 3-25075 + 29' 41" * ' t f 3 -27124 A'- 2 -96223 + 2 "40108 t 31' 7" t + 4' 12" { ;;;. X - - - - tan S - - 1' 38" 1 "99123 - + 2-74741 9 -24382 S 956'-6 cotl " + 25 29 + 3 '18441 -2-75967 o -42474 cosS - - - + 9 "99343 i 20 36 -6 cos i - + 9"97128 W - - - 4- 2 'T'i^QS - -4- 2 "*7 5 3Q8 cos ( S + 0+ 9*93508 (S + i) + 30 33 -2 3 -55630 n - - - A' COS la - - - + 2 -68906 2 -96223 - + 9 '72683 - co - - + H - - 57 47 *0 - cos w - >*7 1 3 *8 r> + 6-28156 + 3 -09715 + 9*72683 + o > *7nqp sin a - - - 9 '66045 b - - + 88 20 '2 sin b - + 9 '99982 3 -03077 nh i *?m.Q / + 3 -37014 + nh OQ m ' 1 u I/ y 1 1 fi u oy i HA 1 48 ' 1 H4 *i *1 TVfpfin tinif^ Acceleration S. T. mean : 1 -8 noon 19 4 *4 Acceleration -^ S. T. mean noon 2 *0 19 4 -4 C KA .0 6^1 '5 - Sid times Star's R. A. - 10 23 *4 Star's R. A. - 10 23 "4 f Im. h - - 4 29 *1 = 67 [Em. h == - - - - 3 31 "9 = 53 IParallactic Z - 39' 7 \Parallactic Z - 36'9 ( t \ i on A ( i } , pp. ./ V */ \ i) J- 5*7 -8 On Eclipses. 14' These angles are for the inverted image; and, being estimated towards the East, the negative values must be considered as towards the West. The decimation of the Star gives for the latitude of Greenwich a semidiurnal arc of 7 h 23 m ; as this exceeds the value of h both at Immersion and Emersion, the Immersion and Emersion will both occur above the horizon. V. CALCULATION OF THE ECLIPSE OF THE MOON, April 30, 1836. The Opposition or Full Moon takes place at 19 b 58 m . For the computation assume the time 20 h O m . 19 h 20 h 21 h hms hms hms }) 5 sR.A. 14 32 51'35 - - 14 35 11 '19 - - 14 37 31 '43 0'sR.A. + 12 h - 14 33 52 '38 - - 14 34 1 '91 - - 14 34 1 1 '45 (time 1 1 '03 ami 9 '28 1 space a = + 15' ' 19 + 3 19*98 + 50' 0" 15 15 -, ,/, '9 + 32 ll <*' = + 32/ 38 " U 19' })'sDec. 14 5 a cor. - - 0'sDec. - - + 15 6 35 1 T~l6 II 191 of + 61' 16" x = + 47 21 + 33 29 20 h 21 h O j // o / n 14 19 58 !; 14 34 32 1 + 15 7 20 + 15 8 6 + 47 21 + 33 29 / ei Ji s - 13' 54 " a +3-01662 a t + 3 -29181 P60'19" cos D +9 -98627 +9'98627. y l+ rS^ P 3 -55859 #, 2-92117 y +3-00289 x +3 -45347 S +19 30'7 tan S + 9 -54942 cot i -0 '33691 cos S + 9 '97431 cos i +9 -96163 9 -99929 3 -55788 23 43 '9 W +3 -47916 +3-47916 ve, it will be readily inferred that the elements of the orbit can at every time be expressed by means of these co-ordinates and velocities at that time. Thus, by proper treatment, the equations of motion may be made to express the differential coefficients of the elements of the ellipse in which (as above) the planet's place and motion near that time are to be determined by the usual formulae. This gives only the momentary changes of the elements : a process equivalent to integration will then give us the total change that has taken place between any one time and any other time. (4) Let IA be the Sun's mass^ m l9 m 2 , rag, &c. the masses of the disturbing planets (the masses being represented by the number of units of velocity which their action at the unit of distance would give in the unit of time), and for brevity let the letter m be used for the disturbed planet; also let x, x lt x z , &c., y, y l9 y a , &c., 2, z l9 z a , &c., be the co-ordinates of the disturbed and disturbing planets at the time t\ x being measured from the Sun towards the first point of Aries (supposed invariable), ?/ being measured towards the first point of Cancer (the plane of the ecliptic being supposed invariable), and z perpendicular to the plane of the ecliptic: let r, r l9 r 2 , &c. be the true radii vectores : also let a, e, ts, z, v, be the mean distance, excentricity, longitude of perihelion, inclination, and longitude of node, of m at that time ; n the mean angular motion (in the instantaneous ellipse) in one unit of time, measured in parts of radius : and let e be the epoch of mean longitude of m, or the angle that must be added to nt, to ^ form in the instantaneous ellipse what in an invariable ellipse is called the mean longitude ; so that the place of m may be calculated at the time tj by supposing it to move in the ellipse whose elements are a, ' + (y-yi) f + (z-*i)'}* r ' 8 > for all the different disturbing planets, we have d*x ux w=-"^- flA - Similarly, putting B for the sum of such quantities as y-y _ and C for the sum of such quantities as Wi f _ * ** __ j. il ft l{^-^) 2 + (y-yO 2 -f (*-*i)*}* ri3 for all the different disturbing planets v we have These are our fundamental equations. (6) To discover the best method of combining these, we must, in conformity with the considerations of (3), express some of the elements in elliptic motion by means of the co-ordinates and velocities of the planet. Now in elliptic motion = -- (velocity) 2 2 1 f/rfa?Y /c/y\ 8 - - the equations of (5) the variation of --- 1 12? J "'"("T// ~'"(l7)l have the variation of -- Also putting h for twice the area passed over in the unit a of time by the radius vector, in undisturbed elliptic motion, the projections of this double area on the planes of #y, yz, and xz, are h cos i, h sin t sin r y h sin i cos v 9 12 152 On the Calculation of Perturbations. dii dx dz d\i dz dx but these projections are respectively x ~- 7-7, V -; -- * ~r-> x , -- z -r-i J dt J dt ' y dt dt ' dt dt ' therefore inferring from the equations of (5) the variations of these latter quantities we shall obtain the variations of A cos i y h sin i sin v, and h sin i cos v. From these we shall obtain the variations of i 9 v, and h: and since h = ^{/Ka(l e 2 )}, and the variation of a is already found, the variation of e will be found. The mean distance and excentricity being known, the place of perihelion is easily found, as there is but one place of perihelion which can give the proper values of v and -7 : and in like manner the epoch is found. This is the general outline of the method which we shall follow. (7) From the equations of (5) we obtain dx d*x dy d*y dz dV\ 2/* / dx dy ~ '*~' * d f 2 or, as the quantity under the differential sign on the first side is = , 1 da dx dy dz a* dt " dt dt dt da ( dx dy dz whence = 2 a I A - \- B -- + C r- from which the variation of the semi-major axis of the orbit is found. (8) Now the longitude of m from the node is 6 v (0 being measured as mentioned in (4) ), and the co-ordinates of m parallel to the line of nodes, perpen- dicular to the line of nodes in the plane of the ecliptic, and perpendicular to the ecliptic, are therefore r cos (0 >/), r sin (0 ") cos i, and r sin (e v) sin i. From these we readily obtain t T = r {cos (0 r) cos v sin (0 y) ccs i sin r} y = r {sin (0 >') cos i cos v + cos (0 v) sin v} z = r sin (0 v) sin i and "hence On the Calculation of Perturbations. 153 dx dr x dO ~-j~ =: -T- -- H r -7- ( } s sin (0 F) cos v cos (0 >') cos z sin y > du dr y de ( \ ~ = -=- + r -7- \ cos (01') cos z cos v sin (0 1>) sin y f a/ at r at \ dz dr d9 cos e - These expressions, it is to be observed, are formed on the supposition that the elements are invariable; which is correct, because the motion in the actual part of the real orbit is the same as it would be in the instantaneous ellipse of that instant, sup- posing that ellipse to remain unvaried. (9) Substituting these in the expression for -^-, at da 2 a 2 dr Af sin (0 y) cos y -f- cos (0 v) cos i sin y J B ( sin (0 v) sin v cos (0 v) cos i cos v C cos(0 v) sin/ which for brevity we shall write ~ ' ~di T ~dt The calculation of A' involves no difficulty ; that of B' is rendered very easy by the use of two subsidiary constant angles, "^ and x where tan ^ = tan v cos i t and tan x = cot y cos i ; whence sin v . in (0 v + V ) +B sin (0 v v) C snucos (0- y). (10) Since ?- 2 ~=k- we have r 2 r= ( 1 ^ a )\ and J p, =rn a 1 , e 2 ) or r-r = wa a r Also therefore , -^ = e sin (0 cr) acr dO na s 6 154 On the Calculation of Perturbations. Substituting these values in the expression of (9), da na 3 e sin (0 si) B - '< (11) From the equations of (5) we find , /x cZ 2 y d 2 # d ( dy dx\ or, by (6), since * _ - y _ = _ (* ^ - y _), &c. ( -7- (A sin i sin v) = /* (B* Cy) -7 (^ sin i cos v) =r /* (A^; Ca;) .... d> dtanv (12) _ = co S V-^ r - 9 d h sin i sin = cos V -7- dt h sin z cos v , a . a . \ h sin cos v -7- (/i sin i sin v) 7t sin i sin y -y- (h sin z cos ^) I = -T~: < cos v r- (h sin i sin y) sin v -7- (& sin .1 cos i/) > A sin z 1 d< di v ' J . A ( z sin v) + B (z cos v) + C (x sin y y cos v) 1 h sin z v J If we substitute for x and y the values in (8), we find x sin v y cos v ~ r sin (0 v) cos z z cot z Therefore -j- = , . 2 . ^ A sin v sin i + B cos y sin i C cos i ! cfa A sm 5 ^ [ Let A sin v sin i 4- B cos v sin C cos a = C' On the Calculation of Perturbations* 155 Then, since h = V/* J{ a ( l e *)}> and n = V/* a ""^ /* an and s= 77V fi/ an therefore dt ^(1 e 2 ) . ,. 2 di 1 . 2 . d tan 2 * (13) -j- r coti cos-* / * s - 2 dt 1 . d (h sin z sin v) 2 + (A sin i cos v) a - cot i cos s z -r- -^ - - - -- ^ -- 2 dt (Acosz) 2 . . f A sin i sin v A sin i cos v C 8 ' A-CO.H- (/i sin i sin v) 2 + (A sin i cos -y- 1 cos i sin y (Ex Cy) + cos i cos v ( A Co;) sin i (Ay B# ) j- = -^- 1 A (z cos z cos y y sin *) + B (z cos i sin v. + x sin ') h ( ^ C cos i (# cos v + y sin y) > Oh substituting the values of x, y, and z, from (8) this is changed to I A( z cot(e >) sin v J + B (z cot (0 v) cosy J C z cot (0 r) cotzl V(l e 2 ) sin an r-r- zcot (0 y) C' r cos (8 v) C' rf* = t \ (h cos z) 8 + (h sin i sin v) 2 -j- (/i sin * cos y) 2 V 2 A ct< I = -~ | A cos i (Ay Bo;) + /t sin i sin v (BsCy) + h sint cos v (Az Ca;)| (y cos * + z si n * cos v) + B (z sin i sin v x cos z) ) C (a; sin i cos y + y sin sin y) f 156 On the Calculation of Perturbations. Substituting the values of #, y, and z, from (8) 1 dh anr i . ( . \ T ' ~dt ~ J(le*) t V m ^ C S * + COS ^ e ~~'') cos * sin v ) + B f cos (0 i/) cos i cos j/ + sin (0 t>) sin r J C sin i cos (9 y) ! " " And as h *Jp J{a (1 , sin (6 tu) or -/77 57- rB' A 7 > - VO e*) VO e ) r B/ c r 1 e whence 7 O x r% v na r and . = - (15) Now ^ g ? is found by differentiating logr=rloga + log(l e 2 ) log {1+e cos (0 which represents the correct value of log r, because by (2) and (4) the same expres- sions are to be taken to represent the place of m (using the elements of the instan- taneous ellipse), as those which are employed in undisturbed elliptic motion (using the elements of the permanent ellipse). Still it is to be borne in mind that the elements vary from one instant to another; and therefore their variation must be taken into account in forming - Thus we have for -- -^ - the rigorous expression d (log a) ^{log(l e 8 )} tljlogQ + e cos(0 CT))| de_ ~dT~ ~~di~ de ' dt d{log(l-f e cos (e CT))} dcr d [log(l-fe cos (0 CT) )} dQ dns '~dT~ dO "cU* This expression, it is evident, has been obtained merely by considering that the place of m is always represented truly by the elliptic formulae applied to the variable elements. But by (2) the motion of m is also to be represented truly by the elliptic formulae for motion applied to the variable elements : and therefore generally the first differential coefficient with respect to t, of r or 9 or of any function of r or 0, must be On the Calculation of Perturbations. represented truly by the elliptic formulae. Now the elliptic formula for - - is dd where r is the same as in the former expression. Making the two expressions equal, d (log q) rf d* de dt d {log (l-fe cos (6 CT))} dor __ rfd "rfT : * The reasoning of this article is general for any expression in terms of the co-ordi- nates of the place of m ; and its general result may be stated thus : The differential coefficient of any function of the co-ordinates (including polar co-ordinates) of m taking those parts only which depend on the elements, is equal to zero. This would not be true if the motion of m entered into the function ; for then the differential coefficient of the function would involve second differential coefficients of the co-ordi- nates, which, as in (5), have not the same form for undisturbed and for disturbed motion. (16) The last equation is 1 da 2e de cos(0 or) de e sin (0 TO) a dt l e*dt I + e cos (0 TO) dt 1 + e cos (0 TO) c/J whence <& S" = djxr _ 1 + e cos (9 TO) / 1 da 2e de\ cos (0 CT) ~dT "~ e sin (0 -or) \ * ' 57 "" I e* ' ~di) ~~ e sin (Q CT) 1+ecos (9 CT) San , na?*J(\ e 2 ) . ,cos (0 CT) ' c sin (e - J)~ ' V ( J - g2 ) ~~ ~~ n c8 . Acos(e^) B- / sin (0 CT) r The factor of B ; in this expression = 1FJ<^1^{^^^ COS CT cos (e CT) { 1 -f 2ecos (0 w) + e 2 cos 2 (0 CT) 1 158 On the Calculation of Perturbations* g at at or (24) The element n (the mean motion) depends entirely upon a, whose variation has already been found : it may, however, be useful to give its variation separately. Since n z a 3 ^^, we have . dn z da ... dn 3 n da 2 no? -r- + 3 TiV - = 0, from which - ------ dt dt dt 2 a dt (25) Collecting, for convenience of reference, all the expressions that we have obtained, we have 164 On the Calculation of Perturbations. n*a*e sin (9 CT) 4- 3tt 2 ay(l-e 2 ) - + ___ r 8n-t 2+e cos - 2VO O cos 2 - efcr naVO e 2 ) cos(0 " : "~ "" f g / (1 _, 8) r sin (0-o) {2+ It will easily be seen that, if we assume the third-differences to be sensible, their effects during one interval will destroy each other in the same manner as those of the first-differences: the only effects omitted are, therefore, those of the fourth- differences, which (except the intervals are extravagantly large) may be neglected. If, however, it is wished to take them into account, the expression is = the sum of all the calculated quantities [a] + - the sum of all the corresponding second-differences , the sum of all the corresponding fourth-differences. SECTION IIL PRACTICAL RULES FOR CALCULATION. (33) Divide the time through which the variations of the elements are to be calculated into equal intervals. Experience alone can teach the calculator what will be the most advantageous length of the intervals : it will depend greatly upon the positions of the disturbing planets, especially Jupiter ; but it is probable that, when Jupiter is nearest, intervals of 10 days each would not be found too long, and that at other times intervals of 20 days each might be safely used. It is desirable to retain the intervals of the same length through the whole of the time, even though the calculations at some parts should be made independently for only each alternate interval, and the others should be filled up by interpolation. (34) All the calculations which follow are to be made for the middle day of each interval. Thus, suppose the intervals were of 10 days each, and we wished to calculate the variations of elements in the 400 days between September 17, 1834, and October 22, 1835, the calculations must be made for 1834, September 22, October 2, October 12, &c. In the following rules we shall express the order of the calculation by the letter p : so that for September 22 (in this instance) p= 1 ; for October 2, p = 2 ; for October 1 2, p = 3, &c. m2 168 On the Calculation of Perturbations. (35) It is supposed that we know tlie planet's mean longitude at the beginning of the time, e ; its mean distance from the Sun, a ; the number of seconds in its mean sidereal motion during one interval, N; its longitude of perihelion, w; its excen- tricity, e; the longitude of its ascending node, v, and the inclination of its orbit to the ecliptic, i: all for the beginning of the time. The mean longitude and the longitude of perihelion are supposed to be measured from the first point of Aries on the plane of the ecliptic, to the node, and then upon the plane of the orbit. With these elements, the planet's true longitude (measured as the others are measured), its radius vector r, and its co-ordinates, x 9 y, z, (of which x is drawn from the centre of the Sun towards the first point of Aries, y towards the first point of Cancer, and z perpendicular to the plane of the ecliptic towards the north) must be calculated approximately for the middle day of every interval. It is probable that an accuracy of 1' in true longitude and of the whole radius vector will be sufficient: but 5000 experience will be the best guide on this point. (36) The proportions -, -, &c., of the masses of the various disturbing planets to the Sun's mass are supposed to be known. The radii vectores r l9 r 2 , &c., the co-ordinates x l9 y l9 2 15 x*, y^ 2 2 , &c., of the various disturbing planets, and A,, X 2 , &c., their distances from the disturbed planet, must be calculated for every middle day. (37) The next step will be to calculate, for every middle day the following quantities : (38) Find the angles ^ and y, where tan y = tan v cos z, and tan % = cot v cos i (y<- and x will therefore be constants) : and calculate for every middle day the follow- ing expressions : B' = A j - sin (0 v+V) + B -^- sin (0 v x) C sin i cos (0 v) C 7 = A sin v sin i + B cos v sin z C cos L (39) Find the angle 0, such that sin =s e (0 is therefore constant), and calculate for each middle day the following expressions (where p 9 as before mentioned, is the ordinal number of the interval) On the Calculation of Perturbations. 169 [ a ] - f'g N sin \" a 3 tan 0V m ^"" g) A 7 + (* N sin I 77 a 4 COS0") (\ * - //a rt \ / \ TJ/ i Sill \y TJT ) I a q _* i ** 3 N sin I" a tan A 7 [ 3 N 8 sin 1 7/ a cos I / 7* \ / 7* / N / (3N^inl 77 anan0)( F -|) S ^^ + ^ + (N^cos0tan|)^^A 7 ,^J_ / tan|\ - { ( 3 N 2 sin 1 7/ a 3 cos ] + I 2 Na -r )r sin (0 w) I V / r \ cos / + f Na tan tan J r sin (0 w) cos (0 17)| B' , a i 2 COS COS = Nrf cot &m<> cos \ sin (e _ w) B , ?>/ > si" ( 9 ~ ro ) cos (9 ro) B' + - - z C' [ ] = - fN sin 1" a* cos ^ ^ ( -^=^ A' + ( N sin 1" a ^)1' \ / r \ sm0/ r ^Nsin l // acot0 > )rB / cos sin 2 1 The quantities within the large parentheses are constant. (40) Collect the whole series of calculated quantities [a], take the first-differences and second-differences, and supply by estimation a second-difference preceding the first and one following the last; and with these form a first-difference preceding the first [a] and one following the last [a]. Then the sum of all the quantities [a] with of the excess of the last first-difference over the first first-difference will be the 24 whole variation of a, in parts of the earth's mean distance from the Sun. Similar Operations performed with respect to all the quantities [N], [e], [BT], [v], and p] will give the whole variations of N, e, or, r, and i 9 in seconds of space; and similar 170 On tlie Calculation of Perturbations. operations performed on all the quantities [e] will give the whole variation of e in parts of unity. These whole variations we shall denote by the prefix . (41) Now, the planet's place at and near the end of the time is to be calculated as if it were moving, undisturbed, in an elliptic orbit, whose mean distance == a + 5 a, excentricity = e + Se, longitude of perihelion == CT + &CT, longitude of node = v + Jf, and inclination = i -f 2 : and its mean longitude in this orbit is to be calculated as if, at the beginning of the time, its mean longitude had been e + Se, and as if, from the beginning of the time, its mean sidereal motion had been N + N in every interval. (42) If the planet's place is to be calculated for a considerable time before and after the day to which we have corrected the elements, it will not, perhaps, be sufficiently accurate to use one set of elements (though this is sufficient for the ordinary ephemeris for the opposition of a small planet). In that case it will only be necessary to terminate the summation of the quantities [a], &c., at two or three different days, and to use the elements, thus corrected to two or three different days, for the calculation of places for times near to those days. (43) If the change in the elements through the whole period appears to be great, the only method of making the calculation accurate will be, to sum the variations for a short time (as perhaps one half or one third of the whole period) and, correcting the elements, to use these corrected elements for the calculation of the co-ordinates and other quantities which are to be used in the calculation of the variations for the next part of the period. It is probable that this process will seldom be found necessary, except when the planet near its aphelion is acted on by powerful disturbing forces; a circumstance which occurs sometimes in the perturbations of ENCKE'S Comet. (44) It is only necessary to add, that the formulae above suppose the longitudes to be measured from an invariable line on an invariable ecliptic. To take account of the alteration in the ecliptic and the first point of Aries, the longitude of the node must be increased by general precession during the interval diminution of obliquity during _the interval X sin v X cott; the longitudes of the planet and its perihelion from the node must be increased by diminution of obliquity x sin v X cosec i : the complete mean longitude therefore of the planet, and longitude of its perihelion, must be increased by general precession + diminution of obliquity X tan x siri v. And the inclination must be increased by diminution of obliquity X cos v. On the Calculation of Perturbations. 171 The true longitude, calculated with the elements -thus further corrected and the mean sidereal motion, for any considerable interval before and after the day for which the elements are computed, must also be affected with precession proportional to that interval. . If, however, in the process of calculating true longitudes, the motion of precession be added to the mean sidereal motion, and if the same motion of precession be applied to the longitudes of the node and perihelion (neglecting for short times the effect of change of obliquity) it will not be necessary to take account of precession afterwards. G. B. AIRY. OBSERVATORY, CAMBRIDGE, Dec. 3, 1834. 172 ON THE DETERMINATION OF THE LONGITUDE FROM AN OBSERVED SOLAR ECLIPSE OR OCCULTATION. BY W. S. B. WOOLHOUSE, HEAD ASSISTANT ON THE NAUTICAL ALMANAC ESTABLISHMENT. AN accurate observation of a Solar Eclipse, or Occultation of a Star by the Moon, furnishes a favourable opportunity for the calculation of the longitude. This cal- culation may be effected by various methods, most of which are well known to astronomers : amongst the most simple and practically useful may be noticed the method of the late Dr. Young, and the improvements on the same by Mr. Thomas Henderson, now Astronomer Royal of Scotland, (see Nautical Almanacs from 1827 to 1833, inclusive); also two methods by Mr. Edward Riddle, and another by Mr. Thomas Maclear, published in the Memoirs of the Royal Astronomical Society, vol. iv. pages 305 and 531. To obviate the difficulties in the way of the calcu- lation, these methods, as, indeed, all others that have come within my observation, suppose in the first instance that the estimated Greenwich time will suffice to take out the Moon's declination accurately from the ephemeris; or that the motion of the Moon in her orbit is uniform throughout a wide interval of time ; consequently, when a good result is to be obtained, and the error of the estimated longitude is considerable, the computer is generally obliged to repeat the calculation with more accurate data, deduced for the Greenwich time according to the calculated, instead of the assumed, longitude. A method well adapted to computation, and, in all cases, free from inaccuracy or roughness of approximation has long been wanted. The following brief discussion of the problem is submitted by way of continuation of my paper on Eclipses, which forms the Appendix to the Nautical Almanac for 1836, and has for its object an easy, practical, and, at the same time, a correct solu- tion. It is proposed, also, to supersede the necessity of having recourse, in these calculations, to the elements usually printed in Occultation lists, the use of which materially augments the chances of inaccuracy; and furthermore, to reduce the processes of calculation, for an Occultation, to plain and simple rules for the use of those who may be unaccustomed to analytical formulae. In the case of an Eclipse of the Sun, the apparent time of observation being converted into arc, at the rate of 1 5 for an hour, will show the true hour-angle of the Sun's centre at that instant; and as the declination of the Sun is never subject to a very rapid daily variation, it may be taken out from the Ephemeris with tolerable accuracy by the approximate Greenwich time, deduced from an estimated longitude or a rough longitude by account. On the Determination of Longitude, 173 In the annexed figure, let Z represent the position of the zenith, S the Sun and c'c'c' his limb. To illustrate the principle and simplify the reasoning that enters into the present investigation, it will be convenient to imagine, merely by way of convention, the limb c'c'c' of the Sun to be an apparent one as affected by a parallax equal to the relative parallax of the two bodies : on this supposition, let s be the true place and c c c the true appear- ance of the limb as it would be seen from the centre of the Earth. Then, by the theory of the effects of parallax, the true semidia- meter Sc' of the Sun will represent the fictitious semidiameter sc as augmented by the parallax ; and if any point c be taken in the fictitious limb cccit will be transferred to a corresponding point c 1 on the true limb of the Sun ; consequently, the true limb of the Moon M being brought in contact with this disc, the parallax will exactly reduce her apparent limb to a contact with the Sun's true limb c'c'c'. Moreover, as the hour-angle and declination of the Sun S are known at the time of observation, and as this position is now viewed as an apparent one, the effects of the parallax or, in other words, the calculation of the relative right ascension and declination of s and the diminished semidiameter s c follows directly from the equations (2) of my paper on Eclipses, page 103. The problem is thus reduced to the deter- mination of the corresponding Greenwich time when the true disc of the Moon comes in contact with the given disc ccc placed at a given relative right ascension and declin- ation; and every consideration relating to parallax is hence eliminated from the inquiry. Assume, at the right ascension h the hour-angle the declination or the semidiameter the right ascension S the decimation ) cos M A 3 = p P cos M cos e = a + A a $=$+ A cos (0 tan (A) 174 On the Determination of Longitude in which M may be regarded as the parallactic angle, and e the altitude of the Sun, the latter of which will be wanted to take out the diminution of the Sim's semidiameter with the table on page 1)5, to get , cos (D) or, as the small arcs may be assumed proportional to their sines, cos (D) The time of the Moon's passing over this angle, or the time elapsed in passing from M to m is therefore -- -. - x ' , which deducted from t 0) there results, for the A! COS (D) instant of contact, or observation, The corresponding Greenwich time = f A . (Q)~( A ) AsinCv + VO A t A a cos (D) The longitude from Greenwich is hence determined by taking the difference between the Greenwich time and that of the observation, previously making them both apparent or both mean by the application of the equation of time if necessary ; and it will be when the Greenwich time is the For an Occultation of a Star by the Moon the calculation will, in some respects, be slightly abridged. The characters AI, D 1? must then represent the absolute motions of the Moon in right ascension and declination ; the semidiameter k 's declination and the log. cosecant of the reduced latitude. To the same log. add the log. cosecant of the >fc's declination the log. secant of the reduced latitude and the log. secant of the hour-angle corrected. These sums will be the prop. logs, of two arcs. The former arc to have the same name as the latitude. The latter to have 178 On the Determination of Longitude The sum of these two arcs, having regard to their names, will give the correction to be applied to the >K J s declination to get the declination corrected. To the sum (S^ add the constant log. 1*1761 and the log. cosine of the >fc's de- clination corrected ; the sum will be the prop. log. of an arc in time, to be subtracted from } the *' s ri S ht ascension, when it is j^f } of the meridian, to get the >K's right ascension corrected. In the hourly ephemeris of the Moon, fix on a convenient time at which her right ascension is near to that of the star corrected ; and, for this time, take out the right ascension, the declination, and their hourly variations. Subtract the common log. of the difference between the corrected right ascension of the star and the right ascension of the Moon from the common log. of the hourly motion in right ascension; to the remainder add the constant log. 0'477l; to the same remainder add the prop. log. of the hourly motion in declination. The former sum will be the prop. log. of a time to be subtrlcted from } the assumed time when *' s R ' A ' is { ST* } *<"> J >S R ' A ' to get the time corrected; The latter will be the prop. log. of a correction of the }) 's declination, to be applied with- To the common log. of the hourly motion in right ascension, add the log. cosine of the J) J s corrected declination ; and to the sum (S 2 ) add the prop. log. of the hourly motion in declination and the constant log. 7' 1427- The result will be the log co- tangent of the 1st orbital inclination* and must take is { Sout } f > ., To the prop. log. of the difference between the star's declination corrected and the Moon's declination corrected add the constant log. 9 '43 54 and the log. secant of the preceding orbital inclination ; and from the sum deduct the prop. log. of the horizontal parallax. The remainder will be the log. secant of the 2nd orbital inclinationf which must have the name -VT' [ when the observation is an { immersion [ emersion Add together the two orbital inclinations, having proper regard to their names ; and to the log. cosecant of this sum add the preceding sum (S 2 ), the prop. log. of the horizontal parallax and the constant log. 8 '1844. The sum will be the prop. log. of a correction to be applied to the time corrected to get the mean time at Green- wich : it must be , f ] r when the sum of the orbital inclinations is < ' * With the parallel of declination. t With the Moon's limb. from an Observed Occultation, fyc. 179 By applying the equation of time from p. IT. of the ephemeris there will result the Greenwich apparent time, and the difference between it and the apparent time of observation will show the longitude of the place from Greenwich ; it will be ' > when the Greenwich time is -j j= r ^ e r I than the observed. EXAMPLES. I. SOLAR ECLIPSE. For a Solar Eclipse take the example directly calculated in the Appendix to 1836, page 139: Suppose the beginning of the Solar Eclipse on May 15, 1836, to be observed to take place at l h 36 m 35 8< 6P.M., apparent time, in latitude 55 57' 20" N., and longitude about 12 m W. Here we have h m Observed apparent time - 1 36 "6 Longitude- r 12'0 h = + l h 36 m .35-6 Greenwich apparent time 148 '6 = + ' 24 8'- 9 Equation of time - - - - 3 *9 Greenwich mean time - - 1 44 '7 We hence take from the Ephemeris, * = 3 h 29 m 19% S = + 18 57''6, = 9 "99902 P r 3'51267 cos (A) + 9*96060 - - +9 '96000 p - - 9*99902 cot/- +9*83256 cos/ +9 "75001 F- - 3-51169 e+3i 50 7 7 tane- +9*793i6 G- +9*71061 cos/ - 9 -75001 $+18 57 -6 61183 + ^+50 48'3 cos - +9 '80069 B - +9 '78899 p - +2-87353 (1) +9-92162 check +9 -92162 cosD 9*97484 tan (A) + 9 '64936 + 2 -89869 tanM +9*57098 8 7 >9 const. 7 '92082 cogM + ^ -97180 - - +9 '97180 6 -6 - - +0-81951 tan (0+S)+0 -08861 cos +9*81719 (A) + 24 2^3 + 4858 /< 3.tan- +0-G6041 B- +9 '78899 s +TT^6 p '- +3 ' 51l6i) + 33-3 '- - - - AS - +33 7 18"-4 - - +3 '30068 S +!9 30-9 cos - 9 '97430 (2) ff 15/ //>g + 2-89923 (1) (2) dim. - 1 1 -6' P- - 3 '51380 const. 8-82391 , . Q0 .o-. const 9 "43537 ff Q - 1 O O O O " - {log.- - +1-72314 * H.49'6 2-94917 A + O h O m 52 8 '86 A 30 27 '9 3 29 19 oc n 3 30 12 ^. 180 On the Determination of Longitude By inspecting the hourly ephemeris of the Moon's right ascension on May 15th with = 3 h 30 m 12", the most eligible time to assume is evidently (i) = 3 h O m s ; at this time we have (A) = 3 h 30 m 42 8 '84, (AO r= 2 m O s< 68, (D) = + 19 31' 34"'0, (DO = + 9' 55"'2, () = 3 h 29 m 31-57, (0 = + 9 S '89, (5) = + 18 58' 2l"'4, (5i) = + 34"-8 : with these we proceed as follows : (A,) - - 2 0-68 9'89 (S } - - + 9 55 -2 - + 34-8 ()- - A + - i 5079 h m s 3 29 31 -57 52 '86 AS + - + 9 20 '4 o / // 18 58 21 -4 33 18 -4 GO' - 3 30 24 -43 Oo) + 19 31 39 '8 (A) - - 3 30 42 -84 f(b) \lntr -(A) - 18 -41 _ i o.f)^o^ ' log. A,- - 2 -04450 D + 2 '74850 (1) m - - const. - 9 -22055 3 -55630 /log- - 9 -22055 1 -96905 log- - 2 77685 ( I 7 33"-l O h 9 58 8 '2 (D) + 19 31 34 -0 (0 300 DO + 19 30 '9 'o + 2- i\ 1 O OU 1 o (^o) + 19 31 39-8 k 1 38'9 cos (D) - - const. - - n - - 9 '97428 2 -04450 1 -17609 3-19487 (2) 19 41 '2 tan^ 9 '55363 (1) (2) COS rj - - +9 '9/384 k 1 '99520 A - - 1 ^6904 3 -26196 V - - + 92 55 '2 rj y- 112 36 -4 - corr. l h 4 m 38 ? '5 T cos^- 8 -70708 - - sin 9 '96528 A - - const. - - 3 -26196 3 -55630 6-78354 (3) 3-58867 (3) (2) corr. 45 23 '3 3 56 -0 1 49 19 '3 1 36 35 -6 Greenwich mean time Equation of time Greenwich apparent time Observed Longitude - 12 43 7 W. of Greenwich. from an Observed Occupation, fyc. 181 II. OCCULTATION OF A STAR. Suppose, at Bedford, on January 7? 1836, in latitude 52 8' 28" N., the Immersion of i Leonis to be observed at 10 h 39 m 22 s * 4 P.M., apparent time, and the estimated longitude to be about O h l m W. Required the longitude ? Apparent time (observation) - 10 39 Longitude 1 W. Apparent time (Greenwich) - 10 40 Equation of time - - - - - Mean time (Greenwich) - - - 10 47 Latitude N. 52 8 28 Reduc. - - - 10 57 N. 51 57 31 Reduced or geocentric latitude. For Jan. 7, at 10 h 47 m , we find, from the Ephemeris, O's R.A. .= 19 h 12 m 40', D 's dec. = N. 15 50', and }) 's equ. hor. par. = 56' 1"*9. O's R.A. 19 12 4Q 8 App. time - - 10 39 22 R. A. meridian ------ 5 52 2 10 23 26 's hour angle E I in ti \ in a time - arc - corr n . - - *'s hour angle E. corr d . - - 4 31 24 ""67 51' _J7 67 34 P. L. }) 's hor. par. - '5068 corr. for lat. - - - - 9 P. L. corr d . hor. par. - '5077 sec. red. lat. - - - - '2103 cosec. hour angle - - '0333 sum (SO 7513 cos. }) 's dec. - - - 9 "9832 const.log. 0*3010 P. L. corr n . - - - - i -0355 P. L. corr d hor. par. - 0*5077 p$a- rf w - '5077 sec. *'s dec. - - - - 0*0150 - - - cosec. --.--- 0*5876 cosec. red. lat. - - - - 0*1037 - - - sec. - '2103 N. 42' 33" *0 P.L. 0^6264 " sec ' Cotr * hour gle OJ4184 S. 3 23 '9 P. L. ----- 1 7240 corr 11 . - - - *'s dec. - - N. 39 9*1 N.14 58 38 *8 *'sdec. corr d . N.15 37 47 '9 corr 11 .- - - - - *'sR.A. - - 10 23 26 *39 *'s R. A. corr d . 10 21 13*83 sum (SO ---- 0*7513 const, log. - - - 1 "1761 cos. - - - --- 9 '9836 --- 1 '9110 On referring with the *'s corrected R.A. to the hourly ephemeris of the Moon, it will evidently be most convenient to take out the data at ll b : for this time we have 3) 's R. A. = 10 h 20 m " 58" -47, hourly motion D 's R.A. = 2 m 2 s '9, }) 's dec. = N. 15 47' 1'1"*0, hourly motion D 's dec. = S. II 7 41"*5. NAUTICAL ALMANAC, 1837. APPENDIX. n 182 On the Determination of Longitude h m s *'s corr d . R. A. - 10 21 13 '83 J)'s R. A. - - - - 10 20 58 -47 fdiff. ...... 15 '36 \common log. ..... 1 "1864 com. log. h. m. }) 's R. A. - 2 '0896 Remainder - - '9032 - - ........... '9032 const.log. ------ 0-4771 P. L. h. m. D 's dec. - - - 1 '18/4 corr n . --- 729'9 P.L. 1 '3803 corr". - - S. l' 2/' '7 P.L.2 '0906 Time assumed 11 00 - })'sdec. - -N.15 47 11 '0 Timecorr d . - 11 7 29 -9 }> 'sdec.corr d .N. 15 45 43 '3 o / // com.log. h m. })'sR.A. - - - - 2 '0896 * 's corr d . dec. - - - N. 15 37 47 '9 cos. 3>'s corr d . dec. ------ 9 '9834 J, 's - - - N. 15 45 43 '3 sum (S 2 ) - -. --- - ---- 2-0730 (Jiff. (# S. of }>) - - 7 55 '4 P.L. h.m. }'sdec. ...... 1 '1874 < pl , - const. log. ---------- 7-1427 lKJj ; . _ L const, log. ----- 9 '4354 1st Orb. incl. - - N. 2134 / cot. OM031- -sec. ,,,,-,-- 0*0315 2ndOrb.incl.- - S. 6l 9 sum S. 39 35 corr". 19 44 '5 P.L. -9599 Time corr d . 11 7 29 '9 Green w h mean time - - 10 47 45 -4 Equation of time- - - 6 31 '0 Green w h app. time - - 10 41 14 *4 Observed - 10 39 22 '4 Longitude 152'OW. P. L. }) 's hor. par. - - '8232 '5068 '3164 0-1957 2 -0730 -5068 8 '1844 nm f^> ~\ P. L. }) 's hor. par. - - P.S. The principle of reversing the effect of the relative horizontal parallax on the position of the Sun, instead of using the actual effect on the position of the Moon, may be advantageously employed in the direct calculation of an Eclipse for a particular place. It will only be necessary to use the parallaxes for the Sun viewed as an apparent position, and to diminish the semidiameter by the amount derived from the table on page 175. Thus, it appears, at the beginning of the Eclipse, for instance, that the contact may be mathematically tested in two ways. First, we may apply the actual effects of the parallax to the true position of the Moon, then augment her semi- diameter, and thus establish a contact of the limbs. But, if we reverse the operation, and consider the Sun to be an apparent body under the influence of the relative paral- lax, then clearing it from this supposed influence by reversing the parallax, and from an Observed Occidtation, fyc. 183 diminishing the semidiameter, a contact will similarly be established with the true limb of the Moon ; and this principle, in its application to solar eclipses, possesses an advantage similar to that derived in the case of an occultation, by considering the Star as an apparent place. (See Appendix to Nautical Almanac for 1836, page 123*.) The formulae, Nos. 2, 3, 4, and 5, pages 130 and 131 may, according to this method, be supplied by the following : P' = p (P *) ro = P' cos / Q t = [9 '4180] Q 2 = [9 '4180] m sin s- [9 -43537] P 3. * = -- cosD A h in minutes = [7 '92082] k sin h (A) = h A h tan 6 == cos (A) cot / G r= cos (A) cos / tanM= ^ --tan (A) tans = tan (6> + S) cos M check - - - B =: cos M cos e sin 9 G cos (6 -f 5) B er = ff diminution for e i f phas*e, A f ^^ \ annular j r [ s 4. * = 5j A = *oin* A t = Qi A cos /i A &i = Q a sin (A) 5. ^o=5 + A^ '= A y = ( A a) cosD yi=(i A a cos D a: r= (D + ' corr.) 5 ^ = D! A 5, * This was inadvertently ascribed to Carlini j Professor Henderson, by whom a paper has appeared upon this very point, in the Quarterly Journal for 1828, page 411, informs me that the method has been long in practice, and that it was employed at an early period by Dr. Maskelyne. 185 ON THE ELEMENTS OF THE ORBIT OF HALLEY'S COMET, AT ITS APPEARANCE IN THE YEARS 1835 AND 1836. BY LIEUT. W. S. STRATFORD, R.N., Supcriuteudcnt of the Nautical Almanac. THE object of the present paper is to afford the most accurate means of determining the Elements of the Orbit of Halley's Comet, at the instant of its Perihelion Passage in 1835, from all the Observations of that Body; and to explain in detail the various operations which have been performed at the Nautical Almanac Office for its accomplishment. It was originally intended to trace the Comet's history from the period of its return in 1759, but this has been rendered unnecessary by the masterly address of Mr. Airy, the Astronomer Royal, to the Fellows of the Royal Astronomical Society, at their annual general meeting in 1837, on tne occasion of presenting the gold medal of the society to Professor Rosenberger, " for his elaborate calculations relating to the return of Halley's Comet." It is impossible to mention Mr. Airy without, at the same time, acknowledging the cordial co-operation which the Author of this paper has expe- rienced from that gentleman, not only in the particular instance of the cometary discussions, but at all times, and on all occasions, in which matters connected with the perfection of the Nautical Almanac and the interests of science have been con- cerned. In the SUPPLEMENT to the NAUTICAL ALMANAC for the year 1833, with the view of attracting the early attention of astronomers to the subject, there was first given an Ephemeris of the Comet, from Aug. 3, 1835, to Feb. 11, 1836, founded upon the fol- lowing elements of its orbit, given by M. de Pontecoulant in the Conn, des Terns pour rAn 1833, page 112. Passage of the perihelion, 1835, Nov. 7 '2, Paris mean astronomical time. o / // Place of the perihelion on the orbit - - - - 304 31 43 Longitude of the ascending node -----55300 Inclination of the orbit - 17 44 24 Ratio of the excentricity to the semi-axis major - 0*9675212 Semi-axis major 17 '98705 Motion retrograde. This Ephemeris was reprinted in the NAUTICAL ALMANAC for 1835 ; and as the principal difference of M. de Pontecoulant's elements from those of M. Damoiseau related to the time of passage of the perihelion, a double Ephemeris was added, for the purpose of affording means of an early rectification of this element. The double NAUTICAL ALMANAC, 1839. APPENDIX. O 186 On the Elements of the Orbit of Halleys Comet, Ephemeris contained, for each 8th day, from Aug. 7, 1835, to Feb. 7, 1836, the Right Ascension and Declination, each to minutes, of the Comet, on two suppositions of the arrival at the perihelion, viz., Nov. 3'2 and Nov. 11'2, 1835. In the same work were also given the co-ordinates of the Sun and Comet, together with a plan of the Heavens, showing, from three different sets of elements, the paths of the Comet amongst the fixed stars, and the relative position of the Comet in each on certain days, so as to indicate the direction in which the Comet should be sought for, with the greatest probability of its rediscovery. It appears that the Comet was first seen at Rome by M. Dumouchel, Director of the Observatory of the Roman College, at O h 20 m , sidereal time at the place, on August 5, 1835, in Right Ascension 5 h 26 m , and Declination +22 27'. (Ast. Nach., No. 288.) It was observed generally in Europe after the 20th of August. From a comparison of observations made at the latter end of August with the double Ephemeris, it was estimated that the Comet would arrive at its perihelion about 8 '5 days later than the time stated by M. de Ponte'coulant. With a view to a nearer approximation to this element, another double Ephemeris was published on September 30, 1835, containing, for the month of October, 1835, the places of the Comet, on the supposition of the perihelion passage occurring respec- tively on Nov. 15 '1935 and Nov. 16 '1935, astronomical mean time at Greenwich. Additional observations indicated that Nov. 16 '1935 might be adopted for the time of passage, without much liability to error. With this time, and the other ele- ments of Pontecoulant unchanged, an Ephemeris was computed from Aug. 20*5 to to Sept. 30*5, 1835, which, united with the October Ephemeris computed previously from the same elements, embraced the period between Aug. 20*5 and Oct. 31'5, 1835. With this and six other Ephemerides computed in a similar manner from elements in which a small variation was given to each in succession, whilst the other five remained constant, a general Ephemeris was formed for the same period, in which the Right Ascension and Declination consisted each of one known and six unknown quantities. Having collected 56 Right Ascensions and 56 Declinations from roughly-reduced observations, made between Aug. 20 and Oct. 19, 1835, with these and the corre- sponding Right Ascensions and Declinations interpolated from the last-mentioned Ephemeris, there were formed 112 equations of condition, from which were deduced corrections for the assumed elements. From these approximate elements an Ephemeris was immediately published for the month of November ; but there being no doubt of some error having crept into the calculations, a revision of the whole was entered upon, and the following results ulti- mately obtained. Perihelion passage, 1835, Nov. 1 5/93546, Mean Astronomical Time at Greenwich. Semi-axis major - - - . -^ ... -^ ;r .... 18*0779386 Ratio of the excentricity to the semi-axis major '9675509 o / // Inclination of the orbit - - - - - - - 17 45 56 '7 Longitude of the ascending node 55 8 21 *2) From Mean Equinox Longitude of the perihelion on the orbit - - 30432 9 '2j of Nov. 15, 1835. at it # appearance in the Years 1835 4" 1836. 187 With these results an Ephemeris for the month of December was prepared, and pub- lished on December 1, 1835. It now remained to ascertain, by a rough comparison with observations, whether these elements were sufficiently approximate for the calculation of perturbations and their own final rectification, and for this purpose the following comparisons were made. Date. Right Ascension. Declination. 1835. Aug. 20 '5091 Observed. Computed. O-C. Observed. Computed. O-C. h m s 5 40 52 h m s 5 40 54 2 + 23 30 -0 1 + 23 29 '4 i + -6 Sept. 2 '6526 5 52 10 5 52 12 2 25 10-4 25 10 'I + 0*3 Oct. S'3122 8 36 49 8 36 49 + 57 53'7 + 57 54 '6 -0-9 Nov. 8 '2233 17 15 1? 14 59 + 1 12 51 7 12 51 '2 0-5 The observation of August 20 was made at Dorpat by Professor Struve ; that of September 2, at Hayes, by the Rev. T. J. Hussey; and those of October 8 and No- vember 8, with the meridian instruments at Cambridge, by Professor Airy. The results of these comparisons showed that the elements represented the orbit with sufficient accuracy for the purposes in view, and the calculations were imme- diately commenced. The first part of the Series containing the Apparent Right Ascension and Declination and the Logarithm of the true distance of the Comet from the Earth, between August 1'5, 1835 and March 3T5, 1836, was published on December 30, 1835, with the view of affording early facilities for the reduction of the observations of the Comet throughout the whole period of its probable visibility. It is here reprinted in a different form, in Table X, the Right Ascensions being expressed in arc instead of time. The various calculations relating to the Ephemeris of the Comet were performed agreeably to the method described by Mr. Woolhouse, in the Appendix to the Nau- tical Almanac for 1835, and those relating to the Perturbations by Professor Airy's method, in the Appendix to the Nautical Almanac for 1837, using in all cases the data from the Nautical Almanac. In order to prevent confusion, it has been deemed expedient to alter the notation occasionally; and, for facility of reference, it is here collected and arranged in order of the letters of the small italic, the small roman, the large roman, and the greek alphabets. NOTATION. a The semi-axis major of the Comet's orbit, at mean noon of July 30, 1 835. [a] The variation of a during one of the equal intervals into which the whole period, through which the variations of the elements are cal- culated, is divided. o 2 188 On the Elements of the Orbit of Halley's Comet, la The whole variation of a in any given number of intervals, from July 30-0, 1835. e sin 1" ' I 2 > c. J c 2 > Constants used in the calculation of the Variations. &c. e The ratio of the excentricity to the semi-axis major of the Comet's orbit. \e\ The variation of e during one interval. 5 r- ) ^sinz cos( = dimin. of obliq. x sin v tan i %i = dimin. of obliq. X cos v Iv = dimin. of obliq. X sin v cotan i the amount of diminution being reckoned from July 30, assuming O r/< 457 as the annual diminution. The results are inserted in Table IX. They represent for any date in the Table the 196 On the Elements of the Orbit of Halleijs Comet, total amount of alteration which each element of the orbit of July 30*0 has under- gone by the action of all the disturbing Planets. Having obtained these values for every fourth day, commencing with July 30, 1835, the elements of the perturbed orbits were obtained for each fourth day, by the suc- cessive addition of each , e, &c., to the original elements ; the mean longitude on July 30 having been taken c rr CT -j- nt t being the interval in days between July 30 '0 and the assumed time of passing the perihelion, viz., Nov. 15*93546. It now only remained to compute the Right Ascension and Declination of the Comet from each set of perturbed elements, and by a comparison of the results with those in the original Ephemeris derived from the imperturbed elements of July 30'0, to ascer- tain the alterations produced by the disturbing Planets on the Right Ascension and Declination of the Comet. The value of e for the orbit of each date was assumed to be the mean longitude in that orbit on July 30, arid was in each case reduced to the date with the mean motion belonging to the orbit, as determined from its semi-axis major. With the longitudes v and cr, reduced to the true equinox of each date, by applying precession and nutation, the apparent Right Ascension and Declination of the Comet were determined from each set of perturbed elements for every fourth day, from July 30, 1835. These calculations were conducted in a manner precisely similar to those for the original Ephemeris. Subtracting the and I of the original Ephemeris from the and I derived from the disturbed elements, the effect of perturbation upon the Right Ascension and De- clination for each fourth day, from July 30, was obtained, and thence, by interpo- lation, the daily effect. These perturbations are inserted in Table X. They are to be applied with the proper sign to the Right Ascension and Declination of the Comet in the same Table, to fur- nish the apparent Right Ascension and Declination, such as should be exhibited by observation, on the presumption that the elements of July 30, 1835, are the true elements of the Comet's orbit at that period. CORRECTION OF THE ASSUMED ELEMENTS. Let it be now supposed that the true elements of the orbit on July 30 *0, 1835, were T + O d '02 P a + '01 Q e + O'OOOl R CT+ 1' S v + 1'U t + 1' V T, a, &c., being the numerical values of the assumed elements on July 30, (page 186), and 0'02 P, 0*01 Q, &c., the corrections due to those elements. at its appearance in the Years 1835 $ 1836. 197 If with the elements T-fO'02, o, e t or, v, i y a right ascension ^ and decimation 1 be computed for the time t in a way similar in every respect to that described in pages 191 and 192, it is plain that t and $ ^ are the variations of right ascension and declination produced by the given variation (0 '02) ofT alone. Now if the elements have been obtained sufficiently near in the first instance to justify the presumption that the variations of the right ascension and declination will be proportional simply to the variation of the element which produces them, then for the true variation of T, viz. 0*02 P, the variation of right ascension will be ( i) P, or reduced to the arc of a great circle, ( cos 5 . P, and of declination (S S,) P. In the same manner the elements T, a+0'01, e, nj t v, i will furnish a right ascen- sion or 2 and declination . 2 ; and the variations 2 , $ 2 will be dependent upon the given variation of a alone. The variations produced by the true variation of a, viz. O'Ol Q, will therefore be ( a 2 ) cos $ . Q in right ascension, and ( 2 ) . Q in declination. By thus varying each of the other elements in succession by a given minute quan- tity, a knowledge is obtained of its separate influence in altering the right ascension and decimation, and hence the influence of the assumed unknown total variations, viz. For variation of e = '0001 R,the variation in J R * A< ~ (""*) cos 5 * R Dec. - O J.) . R . = (-*,) cos Dec. = -W .S _ u Dec, = (* - W . U R. A. = (a ff 6 ) cos 5 . V Dec. = ($ - J.) . V Having the variation of and 5 consequent upon a variation of each element singly, now suppose all the elements to vary together, the total variation of right ascension and declination of the Comet will be + A! P+ A 2 Q+A 3 R+A 4 S+A 5 U+A 6 V = (') cos $ = E + A' t P+ A', Q+ A 7 8 R+ A ; 4 S+ A '3 U+ A' 6 V = (S 7 -S) = E' where P, Q, R, S, U, V are the unknown quantities to be determined. The variations of right ascension and declination determined from given minute variation of elements, as before explained. x , A 2 , &c. 1 \ , A ' 2 , &c. J ' , y An observed right ascension and declination at the time for which and S have been computed. On these principles have the equations of condition in Table XI. been formed. Six different Ephemerides have been computed from six different sets of elements ; and subtracting the resulting Right Ascension and Declination of each from the Right Ascension and Declination in Table X, derived from the original elements, the differences (those of R. A. being first multiplied by cos S,) form the coefficients of P. Q, R, &c. ; indicating, for any given time within the limits of the table, the numerical amount of variation caused by a minute variation of each element. The mode of using the table is as follows : Having a reduced observation of Right 198 On the Elements of the Orbit ofHalleij* Cornet, #c. Ascension and Declination at a given mean time, find, by interpolating Table XI, the coefficients of P, Q, R, &c., for that time : find also, by interpolating Table X, the Right Ascension and Declination , including the perturbations, for the same instant : subtract the interpolated from the observed Right Ascension, and multiply the remainder by cos 5, the product is to be substituted for E, the right hand term in the equations of condition dependent upon Right Ascension. Subtract the interpolated from the observed Declination (North Declination being +, and South ), and the remainder is to be substituted for E', the right hand terni in the equations of condition dependent upon Declination. The unknown quantities being 6, require absolutely only 6 equations for their complete determination, but from the uncertainty attached to observations of Comets, it is desirable to procure as many as possible, and form similar equations of condition, the resolution of any number of which may be effected by the metfiod of least squares. Each observation of Right Ascension and Declination furnishes, conjointly with the Ephemeris, a value of E and E'; and all the equations combined as before men- tioned, and resolved, will furnish the value of the unknown quantities P, Q, R, &c., and hence the corrections to be applied to the assumed orbit of July 30, to obtain the true orbit of the Comet on that day. When from a complete discussion of all the observations deserving of confidence, the assumed orbit of July 30, with the position of the perihelion therein, and the time of perihelion passage, shall have been corrected, the total variation of each of the elements for each fourth day, from July 30, given in Table IX., furnishes a ready means of reducing the orbit and the position of the perihelion to the instant of the Comet's passage by that point. W. S. STRATFORD. TABLES. 200 On the Elements of the Orbit ofHalleijs Comet, TABLE I. Containing, for each Mean Midnight at Greenwich (Astronomical time) from August 1, 1835, to March 31, 1836, the Comet's Excentric Anomaly O), Loga- rithm of the Radius Vector (r), and True Heliocentric co-ordinates (x, y, z,); x, being measured on a line passing through the true Vernal Equinoctial point of the date ; y, on a line in a plane parallel to that of the Equator, and perpen- dicular to the direction of x; and z, perpendicular to the plane of the Equator, towards the North. Date. u Log. of r x y z 1835. O 1 II Aug. 1 '5 23 13 56'58 0-3021016 + o -9934592 + -6196067 + 0-6400825 2'5 23 6 58 *85 0-2990714 o -9942075 6032837 -6364889 3'5 22 59 58 '31 o -2960188 '9949189 5869050 -6328720 4'5 22 52 54 '63 o -2929266 o -9955925 5704610 o -6292300 5'5 22 45 47 '96 -2898106 o -9962267 5539570 -6255636 6-5 22 38 38 '33 -2866660 o -9968209 5373970 0-6218734 7'5 22 31 25-49 -2834906 o -9973750 5207700 '6181573 8'5 22 24 9 -45 '2802842 o -997*869 5040/90 '6144149 9'5 22 16 50 -08 o -2770462 '9983565 4873210 -6106458 10 '5 22 9 27 -50 o -2737772 '9987832 4705020 '6068508 11 '5 22 2 1 '60 o -2704/60 0-9991612 4536180 o -6030291 12'5 21 54 32 -11 o -2671406 '9995002 4366610 o -5991783 13-5 21 46 59 -20 o -2637726 '9997897 4196410 o -5953005 14'5 21 39 22 '77 o -2603706 1 -0000309 4025540 o -5913941 15'5 21 31 42-81 o -2569340 1 -0002-227 3853990 o -5374591 16-5 21 23 59 '20 -2534626 1 -0003650 3681770 -5834953 17'5 21 16 11 -61 -2499532 1 -0004558 3508750 o -5794993 18'5 21 8 20 -35 -2464082 1 -0004936 3335080 o -5754738 19'5 21 25-36 -2428272 1 -0004786 3160740 o -5714190 20-5 20 52 26-12 -2392058 1 -0004070 2980070 o -5673298 21 -5 20 44 23-12 -2355478 1 ^002793 2809760 0'5632107 22'5 20 36 15 '98 Q'2318502 1 -0000940 2633190 -5590588 23 '5 20 28 4 '45 -2281108 -9998470 2455800 -5548718 24*5 20 19 48 -87 -2243320 '9995412 227/720 -5506526 25 '5 20 11 28-62 -2205090 0-9991710 2098/60 o -5463960 26'5 20 3 4-17 o -2166456 o -9987370 1919HO -5421066 27-5 19 54 35-12 0-2127380 o -9982370 1738640 -5377804 28 '5 19 46 l -47 '2087864 o -9976680 1557380 0-5334177 29'5 19 37 23 '12 o -2047902 '9970305 1375330 -5290182 30 '5 19 28 39 -96 0-2007480 o -9963210 1192460 -5245807 31 '5 19 19 51 '84 o -1966086 4-0 -9955375 + 1 -1008750 + '5201040 at its appearance in the Years 1835 < 1836. 201 TABLE I. continued. Date. u Log. of r X y z 1835. Aug. 3 1 '5 Sep. 1 '5 2 '5 3'5 4'5 o / // 19 19 51 '84 19 10 58 73 19 2 0-47 18 52 56 '97 18 43 47-97 o -1966586 o -1925220 0-1883362 -1841010 -1798138 + o -9955375 '9946785 o -9937410 o -9927245 0-9916247 + 1 -1008750 1 '0824220 I '0638820 1 '0452580 1 -0265400 -f -5201040 -5155884 0-5110315 -5064341 o -5017930 5'5 6-5 7'5 8 '5 9'5 18 34 33 '77 18 25 13-86 18 15 48 '02 18 6 16-51 17 56 39'H o -1754778 o -1710878 o -1666426 -1621440 o -1575906 0-9904415 0-9891705 o -9878092 '9863554 '9848072 1 '0077480 o -9888602 o -9698734 o -9508074 o -9316510 o -4971120 -4923859 -4876133 -4827964 o -4779343 10 '5 11 '5 12'5 13 *5 14-5 17 46 55 -37 17 37 5 -46 17 27 9'13 17 17 6-38 17 6 56-59 '1529786 0-1483094 -1435812 '1387936 -1339424 '9831605 0*9814.125 o -9795602 o -9776010 o -9755304 o -9123946 -8930468 '8736058 0-8540718 '8344322 o -4730224 o -4680629 '4630536 o -4579945 -4528812 15 '5 16'5 17-5 18 '5 19'5 16 56 40 '13 16 46 16-54 16 35 45 79 16 25 7'51 16 14 21 '67 o -1290300 -1240534 0-1190126 0-1139044 o -1087290 '9733450 o -9710422 '9686180 o -9660667 o -9633349 0-8147010 7948690 o -7749395 o -7549054 o -7347707 0-4477163 o -4424965 o -4372221 0-4318895 o -4264990 20 *5 21 '5 22 '5 23-5 24-5 16 3 28-09 15 52 26-47 15 41 16-77 15 29 58 -38 15 18 31 -63 -1034856 o -0981718 o -0927882 -0873298 0-0818006 o -9605694 o -9576147 0-9545167 o -9512687 o -9473680 0*7145355 o -6941950 o -6737546 0-6531994 -6325483 -4210495 '4155386 o -4099664 -4043276 o -3986265 25 '5 26*5 27-5 28 '5 29*5 15 6 55 '91 14 55 11 -00 14 43 17-03 14 31 13 '11 14 18 59 '48 o -0761956 '0705142 -0647582 '0589216 o -0530076 o -9443070 '9405810 '9366846 o -9326099 '9283524 -611/866 o -5909151 o -5699451 -5488564 o -5276640 -3928567 o -3870176 -3811104 0-3751282 o -3690735 30-5 Oct. 1 '5 2'5 3'5 4 '5 14 6 35 *82 13 54 1 -63 13 41 16-79 13 28 21 -03 13 15 13 -82 o -0470144 '0409398 '0347846 -0285478 o -0222278 o -9239040 0'9192580 0'9144076 o -9093442 o -9040590 -5063664 -4849564 -4634403 '4418178 -4200841 -3629438 o -3567352 '3504477 o -3440792 o -3376257 5 '5 6-5 7*5 8 '5 9'5 13 1 55 -17 12 48 24 '48 12 34 41 -59 12 20 46 '04 12 6 37'48 -0158266 o -0093420 o -0027756 9-9961268 9 -9893966 '8985456 o -8927934 o -8867936 -8805362 '8/40114 -3982486 -3763035 o -3542575 -3321065 -3098547 0-3310880 0-3244616 -3177458 0-3109374 -3040343 10'5 11 52 15 -64 9 '9825862 4-0 '8672078 + -2875047 + 0-2970345 NAUTICAL ALMANAC, 183U. APPENDIX. 202 On the Elements of the Orbit of Hattey's Comet, TABLE L continued. Date. u Log. of r X y z 1835. Oct. 10 '5 11 '5 12 "5 13'5 14*5 o 1 II 11 52 15 -64 11 37 40 '05 11 22 50 '50 11 7 46 '26 10 52 27 '30 9 '9825862 9 -97569/0 9-9687316 9 -9616898 9 -9545774 +o -8672078 -8601150 : -8527220 -8450138 -8369808 -fO '2875047 o -2650579 '2425212 -2198898 0-1971773 + -29/0345 -2899355 "2827358 o -2754305 -2680199 15 *5 16'5 17-5 18*5 19^ 10 36 53 '09 10 21 3 '22 10 4 57 '41 9 48 35 -00 9 31 55 '85 9 ^473970 9 '9401526 9 '9328506 9 -9254944 9 '9180934 , -8286088 '1743849 -8198842 -1515173 '8107940 -1285853 -8013202 -1055881 -7914509 '0825416 '2605010 "2528708 '2451286 o -2372695 o -2292937 20'5 21 '5 22'5 23'5 24-5 9 14 59 '54 8 57 45 '46 8 40 13 -51 8 22 23 '23 8 4 14 '06 9 -9106550 9 '90318/2 9 -8957622 9 -8882118 9 -8807306 o 7811695 7704582 o 7593024 o 7476850 o -7355907 o -0594537 -0363288 + -0131855 o -0099666 '0331082 o -2211993 -2129819 '2046422 o -1961779 '18/5894 25 '5 26-5 27-5 28 '5 29'5 7 45 46 '69 7 26 59 '92 7 7 53 '64 6 48 27 '88 6 28 42 '66 9 -8732712 9 '8658540 9 -8584958 9 '8512188 9 '8440474 o 7229972 o 7098927 o -6962557 o -6820712 o -6673242 o -0562329 '0/93132 o -1023373 '1252805 -1481181 o -1788723 o -1700299 o -1610593 0-1519619 o -1427398 30-5 31 '5 Nov. 1 '5 2'5 3'5 6 8 37 '86 5 48 13 '56 5 27 30 '00 5 6 27 '36 4456 '08 9 '8370056 9 '8301216 9 '8234252 9'8l69476 9'8107226 o -6519966 o -6360744 o -6195440 o -6023926 -5846093 o -1708276 -1933811 o -2157490 o -2379015 -2598051 o -1333933 -1239252 -1143388 o -1046375 '0948263 4-5 5'5 6-5 7-5 8'5 4 23 26 '85 4 1 30 '13 3 39 16 '85 3 16 47 '94 2 54 4 -57 9 '8047858 9 7991722 9 7939190 9 -7890630 9 '7846406 -5661888 o -5471216 o -5274071 o -5070447 -4860391 -2814225 o -3027204 '3236594 '3442008 '3643039 -0849124 o -0749012 -0648014 o -0546219 o -0443735 9'5 10 '5 11 "5 12-5 13'5 2 31 7-96 2 7 59 '57 1 44 40 '93 i 21 13 77 o 57 39 '86 9 -7806866 9 7772344 9-7743138 9-7719514 9 7701694 o -4643965 '4421295 -4192531 o -3957876 o -3717559 '3839309 -4030404 -4215950 o -4395563 o -4568896 -0340668 o -0237145 '0133293 +o -0029255 -0 -0074825 14*5 15 '5 16'5 17*5 18 '5 34 1 -10 10 19 '56 13 22 '99 37 4 '34 1 42 '58 9 '7689852 97684100 9 7^84498 9 '7691038 9 7703662 o -3471868 '3221121 o -2960645 -2705833 o -2442074 o -4735619 , -48^3424 -5048074 o -5193319 0-5331004 o -0178797 '0282503 -0385803 -0488533 '0590554 19-5 1 24 15 70 9 7722240 + o 2174783 o -5460981 o -0691720 at its appearance in the Years 1835 & 1836, 203 TABLE I. continued. Date. u Log. of r x y z 1835. Nov. 1 9 '5 20-5 21 '5 22 '5 23-5 o / // 1 24 15 70 1 47 41 '88 2 10 59 '30 2 34 6 '25 2 57 1 '23 9 7722240 9 7746596 9 7776506 9 7811692 9 7851854 +o -2174783 o -1904396 -1631328 -1356024 o -1078894 -5460981 '5583170 o -5697534 -5804060 -5902805 o -0691720 o -0791901 o -0890973 -0988819 -1085341 24 '5 25'5 26-5 27-5 28'5 3 19 42 '85 3 42 9 78 4 4 20 '93 4 26 15 '50 4 47 52 '40 9 7896660 9 7945750 9 7998768 9 '8055344 9*8115104 -0800351 -0520802 -f -0240623 o -0039370 -0320279 -5993855 0-6077318 -6153356 -6222141 -6283870 -1180451 o -1274063 0-1366118 o -1456570 '1545361 29-5 30 '5 Dec. 1 '5 2 '5 3'5 5 9 11 '21 5 30 11 '45 5 50 52 '58 6 11 14 '39 6 31 16 '68 9 -8177696 9 '8242774 9 '8309996 9 '8379058 9 '8449658 o -0600360 -0879834 -1158424 0-1435917 0-1712102 -6338764 -6337059 -6428983 -6464802 o -6494756 o -1632477 o -1717897 0-1801603 -1883598 -1963884 4 '5 5-5 6'5 7'5 8'5 6 50 59 '34 7 10 22 -67 7 29 26 '30 7 48 10 '63 8 6 35 '94 9-8521522 9 -8594414 9 -8668076 9 -8742314 9-8816940 o -1986796 0-2259913 '2531207 -2800633 '3068094 o -6519104 -6538097 -6551979 o -6560999 '6565386 -2042471 0-2119395 -2194648 o -2268274 -2340303 9'5 10-5 11 *5 12'5 13 '5 8 24 42 '38 8 42 30 -21 8 59 59 '82 9 17 U -55 9 34 5 77 9 -8891782 9 -8966684 9*9041516 9 -9116158 9-9190510 -3333506 o -3596787 o -3857907 '4116820 o -4373501 o -6565376 -6561188 -6553030 -6541116 -6525640 o -2410765 o -2479692 o -2547123 o -2613094 o -2677644 14-5 15 '5 16'5 17-5 18 '5 9 50 42 '67 10 7 2 '88 10 23 6 '65 10 38 54 '54 10 54 2671 9 -9264462 9 -9337952 9 -9410906 9 '9483274 9 '9554990 -4627882 '4880003 -5129837 o -5377420 o -5622698 o -6506786 o -6434727 o -6459639 -6431681 '6401000 o -2740799 '2802610 -2863110 o -2922343 '2980335 19-5 20 '5 21 '5 22'5 23*5 11 9 43 79 11 24 46 '01 11 39 33 75 11 54 7 '53 12 8 27 70 9 -9626026 9 -9696340 9 '9765896 9 -9834690 9 -9902692 o -5865737 o -6106513 -6345044 '6581395 '6815563 o -6367742 -6332049 o -6294039 -6253846 o -6211567 -3037131 o -3092764 o -3147259 -3200668 -3253015 24 '5 25 '5 26'5 27 '5 28 '5 12 22 34 -49 12 36 28 '40 12 50 9 76 13 3 38'95 13 16 56 '11 9 -9969886 o -0036268 0-0101834 o -0166578 -0230484 o 7047555 o 7277430 o -7505212 o 7730940 o 7954590 o -6167336 -6121230 o -6073370 -6023821 o -5972692 -3304329 -3354646 -3403998 -3452415 o -3499912 29'5 13 30 1 79 o -0293576 o -8176264 -5920045 -3546530 204 On the Elements of the Orbit of Halley's Comet, TABLE I. continued. Date. u Log. of r X y z 1835. Dec. 29 -5 30 '5 31 '5 1836. Jan. 1 *5 2 '5 o / // 13 30 1 79 13 42 56 '14 13 55 39-57 14 8 12 -27 14 20 34 76 o -0293576 '0355838 -041 >286 -0477918 o -0537754 o -8176264 -8395930 o -8613670 -8829480 '9043446 o -5920045 '5865984 -5810555 -5753848 '5695897 -3546530 o -3592290 o -3637218 -3681338 o -3724678 3'5 4 '5 5*5 6-5 !*. 7 ' 5 14 32 47 '08 14 44 49 '48 14 56 42 '60 15 8 26 '05 15 20 71 o -0596792 '0655036 o -0712524 o -0769220 -0825180 '9255554 '9465822 o -9674333 '9881102 1 -0086172 o -5636797 -5576599 -5515331 o -5453091 '5389883 o -3767258 '3809095 '3850229 '3890650 o -3930407 8'5 9'5 10 '5 11 '5 12'5 15 31 26 -37 15 42 43 '65 15 53 52-37 16 4 52 '97 16 15 45 '44 -0880382 -09348/0 o -0988622 o -1041670 o -1094006 1 -0289507 1 -0491251 1 -0691320 1 -0889800 1 -1086656 -5325780 '5260810 o -5195026 -5128475 -5061187 o -3969498 o -4007962 o -4045793 -4083024 o -4119655 13-5 14-5 15-5 16*5 17-5 16 26 30 '28 16 37 7 '59 16 47 37 -41 16 58 '05 17 8 15 70 o -1145670 o -1196668 o -1246992 o -1296674 o -1345720 1 -1282024 1 -1475900 1 -1668241 1 -1859141 1 -2048622 o -4993195 '4924528 -4855227 -4785318 -4714824 o -4155723 o -4191239 o -4226202 o -4260641 -4294566 18 '5 19-5 20 '5 21 '5 22-5 17 18 24-46 17 28 26 '49 17 38 21 '85 17 48 10 '98 17 57 53-91 -1394142 '1441950 '1489146 o -1535766 0-1581812 1 -2236687 1 -2423366 1 -2608652 1 -2792653 1 -2975366 o -4643735 o -4572223 -4500181 o -4427634 '435 1630 o -4327990 o -4360926 o -4393375 o -4425371 o -4456916 23 '5 24-5 25'5 26-5 27-5 18 7 30 -59 18 17 1 '38 18 26 26 -37 18 35 45 '55 18 44 59 -12 o -1627276 o -1672194 o -1716568 o -1760400 -1803700 1 -3156733 1 -3336871 1 '3515778 1 -3693435 1 '3869864 -4281209 -4207380 -4133141 '4058548 '3983598 '4488008 '4518678 -4548926 o -4578756 '4608183 28'5 29-5 30-5 31 '5 Feb. 1 '5 18 54 7-29 19 3 10 -13 19 12 7 73 19 21 '19 19 29 47 70 '1846496 -1888784 -1930580 -1971884 o -2012720 1 -4045150 1 -4219270 4392260 4564090 4731870 -3908298 '3832684 o -3756758 '3680542 '3604040 o -4637230 '4665887 o -4694171 -47*22084 o -4749648 2'5 3'5 4'5 5*5 6'5 19 38 30 '30 19 47 8 -07 19 55 41 '13 20 4 9 '53 20 12 33 -37 '2053086 o -2092994 -2132450 o -2171468 0-2210042 4904530 5073140 5240680 5407210 5572660 '3527285 -3450256 o -3373003 -3295531 -3217829 o -4776857 '4803725 '4830257 -4856463 '4882339 7 * 5 20 20 52 '99 -2248214 -1 -5737210 -3139910 o -4907921 at its appearance in the Years 1835 $ 1836. 205 TABLE I. continued. Date. u Log. of r X y z 1836. Feb. 7*5 8'5 9'5 10-5 11*5 / // 20 20 52 '99 20 29 7 '99 20 37 18 *83 20 45 25 '58 20 53 28 '15 -2248214 -2285944 o -2323276 o -2360212 o -2396750 -5737210 5900680 6063210 6224810 6385450 -3139910 -3061834 '2983541 '2905048 -2826437 o -4907921 o -4933176 -4958136 '4982807 -5007183 12'5 13 '5 14'5 15 '5 16'5 21 1 26'81 21 9 21 '45 21 17 12-17 21 24 59-18 21 32 42 '41 -2432908 '2468684 -2504082 o -2539120 o -2573796 6545200 6704020 6861920 7018960 7175110 o -2747628 o -2668677 -2589599 '2510363 -2431004 0-5031283 -5055107 -5078655 o -5101936 -5124952 17-5 18 '5 19'5 20*5 21 '5 21 40 21 *83 21 47 57 '92 21 55 30 '28 22 2 59 '18 22 10 24 74 -2608110 o -2642096 o -2675730 o -2709030 o -2742006 7330360 7484860 '7638460 7791240 7943220 '2351553 o -2271943 o -2192253 -2112468 -2032570 o -5147712 o -5170232 o -5192495 '5214518 -5236307 22 '5 23 '5 24 '5 25-5 26-5 22 17 46 '98 22 25 5 '86 22 32 21 -41 22 39 33 '93 22 46 43 -20 o -2774660 o -2806996 -2839010 o -2870734 o -2902144 8094430 8244830 8394410 8543290 8691360 o -1952574 -1872502 o -1792374 o -1712136 -1631855 o -5257862 -5279182 -5300280 -5321165 -5341824 27-5 28-5 29*5 Mar. 1 *5 2 '5 22 53 49 '38 23 52 -75 23 7 52 '89 23 14 50 '21 23 21 44 -56 -2933258 o -2964100 o -2994636 o -3024902 '3054882 '8838690 8985370 '9131230 9276420 9420870 '1551516 o -1471069 '1390603 o -1310079 0-1229515 o -5362271 '5382521 -5402550 '5422388 '5442020 3'5 4'5 5 *5 6-5 7'5 23 28 36 -25 23 35 25 -06 23 42 11 -02 23 48 54 -47 23 55 35 -07 '3084602 -3114052 0*3143228 o -3172162 '3200826 9564670 9707780 '9850160 9991950 2 '0133000 -1148859 -1068224 o -0937545 o -0906788 '0826053 -5461461 -5480715 -5499772 -5518650 o -5537340 8'5 9'5 10 '5 11 '5 12-5 24 2 13 '04 24 8 48 "56 24 15 21 -51 24 21 51 -81 24 28 19 74 -3229238 -3257418 -3285348 -3313032 -3340486 2 -0273360 2 '0413220 2 '0552370 2 '0690850 2 '0828730 o -0745275 -0664464 -0583611 o -0502796 o -0421943 -5555845 o -5574191 o -5592349 -5610338 '5628160 13'5 14-5 15-5 16 '5 17-5 24 34 45 -27 24 41 8 '35 24 47 29-21 24 53 47 -56 25 3 '63 o -3367712 o -3394706 0-3421488 '3448034 o -3474364 2 -0966030 2-1102700 2 -1238840 2 -1374320 2-1509200 '0341058 -0260183 o -0179263 o -0098370 o -0017496 '5645820 -5663312 -5680652 o -5697827 -5714849 18'5 25 6 17-54 '3500484 2-1643540 + 0-0063418 o -5731712 206 On the Elements of the Orbit of Halley s Comet, TABLE I. continued. Date. u Log. of r X y z 1836. Q 1 II Mar. 18 '5 25 6 17-54 '3500484 2 -1643540 + 0-0063418 0-5731712 19'5 25 12 29 '15 o -3526392 2-1777300 -0144311 '5748430 , 20 -5 25 18 38 '55 '3552088 2-1910480 -0225203 o -5764996 21 '5 25 24 45 '69 0-3577576 2 -2043100 o -0306062 -5781412 22'5 25 30 50 '83 -3602870 2-2175190 -0386944 o -5797692 23'5 25 36 53 '88 o -3627968 2 -2306750 '0467840 '5813829 24-5 25 42 54 '71 '3652858 2 -2437730 -0548675 0-5829816 25 -5 25 48 53 '50 o -3677556 2 -2568170 o -0629496 -5845670 26 '5 25 54 50 '43 o -3702076 2-2698160 '0710352 -5861395 27-5 26 45 '23 o -3726398 2 -2827560 0-0791168 o '5876977 28 *5 26 6 38 '03 o -3750534 2 ^956460 -0871938 -5892438 29'5 26 12 28 '86 '3774486 2 '3084840 o -0952698 o -5907748 30-5 26 18 IS'Ol o -3798274 2 -3212790 0-1033490 o -5922947 31 '5 26 24 4 '99 -3821934 2 -3340520 + -1114423 '5938052 at its appearance in the Yearn 1835 4" 1836. 207 TABLE II. Containing, for each Mean Midnight at Greenwich (Astronomical time) from August 1, 1835, to March 31, 1836, the Sun's True Geocentric co-ordinates (X, Y, Z,); X, being measured on a line passing through the True Vernal Equinoctial point of the date ; Y, on a line in the plane of the Equator, and perpendicular to the direc- tion of X ; and Z, perpendicular to the plane of the Equator, towards the North. Date. X Y Z 1835. Aug. 1 '5 2 '5 3 '5 4 *5 5 "5 0-6377144 o -6507172 '6635348 o -6761640 '6886010 +o -7239212 0-7139433 o 7037629 '6933840 0-6828106 + 0-3141959 0-3098651 o -3054467 o -3009422 o -2963532 6-5 7'5 8'5 9*5 10 '5 '7008426 7128858 o -7247270 o -7363624 7477904 o -6720445 -6610891 o -6499469 '6386212 0'6271152 0-2916807 '2869258 -2820903 o -2771750 0-2721814 11 '5 12-5 13 '5 14 '5 15'5 o -7590069 o -7700086 o -7807926 07913554 0-8016942 '6154303 0-6035713 '5915402 0-5793399 o -5669735 o -2671100 o -2619630 o -2567409 -2514459 o -2460787 16-5 17-5 18'5 19'5 20'5 0-8118056 -8216860 0'8313320 0-8407414 -8499097 '5544446 '5417562 0-5289113 0-5159127 o -5027664 -2406408 -2351336 -2295588 o -2239171 -2182115 21 '5 22 '5 23 '5 24-5 25 '5 -8588338 0-8675108 o -8759393 -8841147 -8920348 -4894753 o -4760423 o -4624726 '4487694 o -4349377 0-2124431 -2066131 o -2007236 o -1947763 -1887731 26'5 27-5 28 '5 29-5 30 '5 o -8996971 o -9070998 ;9142407 0-9211173 o -9277274 0-4209812 o -4069035 o -3927093 -3784028 o -3639887 -1827156 0-1766055 0-1704449 -1642355 0-1579793 31 '5 o -9340702 + 0-3494706 + 0-1516782 208 0)i the Elements of the Orbit ofHalleys Comet, TABLE II. continued. Date. X Y Z 1835. Aug. 31 *5 Sep. 1 '5 2-5 3'5 4'5 o -9340702 '9401430 o -9459447 '9314/35 o -9567233 + 0-3494706 -3348529 '3201410 o -3053374 o -2904466 + 0-1516782 0-1453338 '1389485 0-1325236 o -1260608 5 '5 6-5 7-5 8'5 9'5 0'9617067 '9664088 '9708324 o -9749755 o -9788376 o -2754731 -2604215 -2452950 o -2300975 0-2148339 o -1195620 o -1130293 0-1064639 o -0998680 -0932431 10*5 11 '5 12-5 13-5 *4 '5 0-9824170 0-9857127 '9887233 0-9914467 '9938820 o -1995069 0-1841211 o -1686809 -1531899 0-1376537 o -0865909 0-0799130 0-0732117 -0664882 o -0597451 15 '5 16'5 17-5 18'5 19'5 o -9960284 '9978838 o -9994476 1 '0007185 1 -0016956 0-1220750 o -1064592 0-0908113 o -0751365 -0594383 -0529836 '0462060 -0394144 '0326112 o -0257979 20-5 21 '5 22-5 23'5 24'5 1 -0023781 1 -0027662 1 -0028587 1 -0026553 1 -0021567 o -0437224 o -0279936 + 0-0122569 '0034839 '0192232 0-0189768 -0121501 + -0053200 0-0015119 '0083432 25'5 26'5 27-5 28'5 29'5 1 -0013618 1 -0002713 0-9988861 o -9972056 0-9952314 o -0349567 o -0506792 '0663847 o -0820709 o -0977301 0-0151719 o -0219959 0-0288126 o -0356207 -0424172 30 '5 Oct. 1 '5 2'5 3'5 4'5 o -9929635 0-9904031 o -9875505 o -9344073 o -9809734 0-1133602 0-1289545 '1445099 o -1600214 0-1754841 o -0492011 o -0559695 o -0627209 o -0694533 o -0761646 5 '5 6-5 7*5 8 '5 9*5 o -9772506 0-9732391 o -9689400 '9643546 '9594834 '1908938 o -2062490 -2215423 o -2367707 0-2519284 -0828530 0-0895174 o -0961551 o -1027644 -1093433 10 '5 o -9543277 0-2670131 -1158903 at its appearance in the Years 1835 $ 1836. 209 TABLE II. continued. Date. X Y z 1835. Oct. 10 '5 11 '5 12*5 13-5 14-5 o -9543277 0'9488880 0*9431659 0-9371623 '9308786 0-2670131 0*2820198 o -2969437 -3117803 '3265255 0-1158903 '1224035 0'1288809 0-1353204 o -1417202 15*5 16'5 17-5 18 '5 19'5 0-9243160 0'9174755 0-9103593 '9029685 o -8953061 0-3411742 0-3557214 o -3701632 -3844938 o -3987093 '1480782 '1543921 0-1606602 0-1668801 o -1730500 20 -5 21 '5 22 '5 23 '5 24'5 o -8873732 0-8791725 o -8707056 0-8619757 -8529850 0-4128050 o -4267767 o -4406199 -4543289 o -4679004 0-1791678 '1852318 0-1912399 0-1971897 -2030800 25 '5 26'5 27-5 28 -5 29'5 '8437366 -8342334 -8244780 0-8144746 -8042254 '4813287 o -4946128 o -5077449 o -5207219 -5335404 -2089085 0-2146737 o -2203735 -2260058 o -2315694 30 '5 31 '5 Nov. 1 '5 2 "5 3'5 o -7937343 '7830035 o -7720366 o -7608375 '7494084 o -5461961 -5586856 o -5710053 -5831521 -5951215 o -2370624 '2424831 0-2478301 0-2531021 '2582969 4'5 5'5 6-5 7*5 8'5 0-7377541 o -7258759 07137773 o -7014629 -6889342 o -6069100 0-6185154 o -6299339 o -6411615 0-6521953 '2634133 -2684502 o -2734059 -2782789 -2830678 9'5 10 '5 11 '5 12'5 13'5 0-6761963 -6632517 -6501038 o -6367569 0-6232138 '6630313 -6/36663 o -6840969 o -6943192 o -7043302 -2877708 -2923865 0'2969137 '3013504 o -3056957 14'5 15'5 16 '5 17-5 18'5 o -6094795 o -5955570 -5814503 0-5671633 o -5527009 0-7141259 o -7237032 '7330599 0-7421914 0-7510947 o -3099473 0*3141040 -3181650 -3221281 0-3259921 19*5 '5380680 o -7597662 o -3297556 210 On the Elements of the Orbit ofHalleys Comet, TABLE II. continued. Date. X Y Z 1835. Nov. 19 '5 20 -5 21 '5 22 '5 23'5 '5380680 o -5232679 '5083063 -4931886 o -4779192 o -759/662 '7682038 o -7764042 '7843640 '7920813 o -3297556 0-3334175 o -3369766 0-3404311 o -3437806 24-5 25'5 26-5 27-5 28'5 '4625022 -4469443 '4312499 -4154234 o -3994705 7995539 '8067783 0*8137524 o -8204754 o -8269446 o -3470239 -3501597 '3531868 o -3561047 '3589124 29*5 30 '5 Dec. 1 -5 2 '5 3 -5 '3833962 o -3672041 -3509002 '3344888 0-3179752 -8331580 6 -8391143 0-8448118 '8502491 '8554240 o -3616093 o -3641943 o -3666671 o -3690266 0-3712725 4 '5 5'5 6-5 7-5 8'5 -3013635 -2846594 0-2678671 o -2509927 '2340384 0-8603357 -8649822 o -8693622 o -8734741 0-8773168 -3734042 -3754208 0-3773217 0-3/91064 -3807744 9'5 10 '5 11 -5 12'5 13 '5 0-2170117 o -1999168 0-1827584 o -1655416 0-1482738 -8808888 -8841886 -8872146 '8899654 '8924400 -3823249 o -3837572 '3850708 -3862649 o -3873390 14'5 15 '5 l6'5 17-5 18 '5 o -1309573 o -1135992 o -0962042 0-078778! 0-0613261 o -8946376 o -8965570 0-8981975 o -8995575 o -9006370 '3882928 '3891256 '3898372 o -3904274 -3908958 19*5 20 '5 21 -5 22 '5 23 '5 0'0438550 o -0263694 -0088756 + '0086187 0*0261103 G'9014350 0-9019513 '9021856 0-9021381 0-9018086 '3912420 0'3914662 -3915681 o -3915477 0-3914051 24*5 25 '5 26-5 27 '5 28 '5 o -0435920 -0610586 -0785044 o -0959239 0-1133131 0-9011976 '9003058 0-8991338 o -8976816 o -8959504 -3911402 0-3907531 o -3902444 0-3896141 -3888627 29'5 + -1306663 -8939408 '3879904 at its appearance in the Years 1835 8f 1836. TABLE II. continued. Date. X Y Z 1835. Dec. 29 '5 30 '5 31 '5 1836. Jan. 1 *5 2'5 + '1306663 o -1479764 '1652420 '1824538 o -1996086 '8939408 o -8916536 o -8890896 '8862483 '8831344 -3879904 -3869975 '3858847 '3846513 '3832999 3 '5 4-5 5'5 6-5 7-5 o -2167012 o -2337263 o -2506797 o -2675558 -2843501 o -8797475 -8760878 0-8721565 o -8679550 -8634839 -3818298 0*3802417 '3785354 o -3767122 0-3747721 8'5 9-5 10-5 11 '5 12-5 0-3010571 0-3176716 '3341886 '3506041 0-3669118 '8587450 o -8537391 -8484678 0-8429315 0-8371324 o -3727154 -3705428 -3682549 '3658521 -3633350 13*5 14'5 15 *5 16'5 17*5 -3831065 0-3991837 -4151367 -4309614 0-4466519 -8310725 0-8247514 -8181733 0-8113392 0-8042515 o -3607043 o -3579612 0-3551061 0-3521401 o -3490642 18 '5 19'5 20 '5 21 '5 22-5 -4622034 o -4776097 '4928658 o -5079681 o -5229109 o -7969121 '7893248 o -7814911 0-7734146 o -7650978 -3458791 -3425862 0-3391866 -3356814 o -3320718 23 '5 24 '5 25'5 26 '5 27-5 o -5376908 -5523017 o -5667400 0-5810008 -5950812 o -7565431 o -7477544 '7387340 o -7294867 o -7200125 -3283588 '3245443 o -3206292 -3166155 -3125034 28-5 29'5 30 '5 31 '5 Feb. 1 '5 o -6089770 '6226830 o -6361972 '6495148 o -6626323 o -7103177 '7004046 o -6902761 o -6799352 '6693855 -3082956 -3039931 o -2995972 o -2951092 -2905308 2'5 3'5 4 '5 5'5 6'5 o -6755458 -6882509 o -7007469 0-7130268 o -7250890 -6586305 o -6476734 o -6365163 0-6251638 0-6136183 -2858629 -2811075 o -2762656 -2713381 o -2663271 7-5 + 07369287 -6018841 '2612341 212 On the Elements of the Orbit ofHalkifs Comet, TABLE II. continued. Date. X Y Z 1836. Feb. 7 '5 8-5 9'5 10-5 11-5 + 0*7369287 '7485434 '7599287 0*7710818 0-7819977 0*6018841 -5899637 -5778589 o -5655759 0-5531174 0-2612341 o -2560599 '2508063 o -2454750 o -2400677 12 '5 13*5 14-5 15-5 16 '5 o -7926742 0-8031068 0-8132926 '8232278 0-8329091 -5404874 o -5276899 o -5147293 o -5016092 -4883346 *234586l '2290318 -2234068 o -2177124 o -2119510 17-5 18 '5 19'5 20-5 21 '5 '8423340 -8514993 -8604026 o -8690409 o -8774127 o -4749097 0-4613391 o -4476267 -4337777 0-4197970 o -2061244 -2002344 -1942829 0-1882717 -1822038 22 '5 23-5 24 ! 5 25 *5 26'5 0*8855150 -8933456 o -9009036 0-9081862 0-9151928 -4056887 0-3914576 0-3771077 o -3626450 -3480724 0-1760802 o -1699033 0-1636751 o -1573979 0-1510/29 27'5 28 '5 29'5 Mar. 1 '5 2'5 0-9219204 '9283680 0-9345352 0-9404191 o -9460190 o -3333960 0-3186195 o -3037472 -2887843 o -2737349 -144/036 0-1382896 -1318348 -1253406 0-1188088 3'5 4 '5 5 '5 6-5 7'5 G'9513338 o -9563625 o -9611028 0*9655541 o -9697146 -2586029 o -2433919 '2281080 0-212/539 o -1973345 0-1122411 o -1056393 o -0990056 0-0923411 -0856490 8*5 9'5 10 '5 11 '5 12 '5 '9735837 o -9771600 '9804420 '9834286 0'986ll85 0*1818541 o -1663172 o -1507290 '1350940 0*1194l68 -0789302 o -0721868 ff -0654212 '0586352 0-0518310 13-5 14 '5 15 *5 16 '5 17-5 0*9885118 o -9906069 G'9924031 o -9939002 '9950982 0-1037026 -0879563 -0721828 -0563861 '0405740 0-0450106 -0381762 0-0313301 -0244738 o -0176109 18'5 4-0*995996l o -0247498 o -0107423 at its appearance in the Years 1835 <$" 1836. 213 TABLE II. continued. Date. 1836. Mar. 18 '5 19-5 20-5 21 '5 22 '5 23'5 24 '5 25-5 26'5 27-5 28 '5 29 '5 30-5 31'5 o -9965947 o -9968940 o -9968942 o -9965953 o -9959996 o -9951064 o -9939175 '9924335 '9906551 '9885840 '9862208 '9835663 0-9806227 o -0247498 o -0089170 + 0-0069177 o -0227492 -0385728 -0543835 0-0701763 '0859477 0'10l6914 0*1174037 0-1330796 '1487153 0-1643064 + 0-1798484 -0107423 '0038708 + -0030020 '0098734 0-0167414 -0236038 -0304584 -0373036 0-0441370 o -0509567 o -0577607 o -0645172 -0713143 + 0-0780601 214 the Elements of the Orbit of Halleys Comet, TABLE III. Containing, for Mean Noon at Greenwich, the Heliocentric co-ordinates (a,-, ar n &c., 2/> 2/n &c., s, z &c.) of the Comet and the disturbing Planets; x, x l9 &c., beijig measured on a line passing through the Mean Vernal Equinox of January 1, 1835; 2/> yn &c -> perpendicular to .T, #,, &c., in the plane of the Ecliptic (supposed invariable); and z, 2 1} &c., perpendicular to the plane of the Ecliptic, towards the North. HELIOCENTRIC CO-ORDINATES OK Date. THE COMET. MERCURY. 1835. X y z #1 2/i *j Aug. 1 + 0-99318 + 1 '74856 o -05926 + o -35692 -06352 0-03711 5 o -99605 1 -68279 '04645 -33668 + -05450 -02532 9 '99827 1 '61585 '03360 o -27709 o -16571 o -01059 13 o -99977 1 -54778 o -02073 o -17940 -25364 + -00555 17 1 -00052 1 '47856 o -00786 + 0-05418 -30220 '02080 21 1 '00046 1 -40815 + 0*00503 o -07972 o -30270 o -03275 25 o -99949 1 -33638 o -01792 '20210 '25798 -03984 29 '99752 1 -26322 o -03079 -29857 0'17949 o -04176 Sep. 2 o -99433 1 -18872 o -04361 "36284 + -08114 o -03913 6 -98992 1 -11270 '05638 o -39447 -02482 o -03297 10 '98408 1 -03500 o -06908 o -39625 o -12912 '02429 14 o -9/670 o -95572 -08165 o -37227 -22519 '01400 18 o -96745 o -87462 o -09409 o -32692 '30845 +o -00292 22 o -95618 0'79l66 -10632 0-26451 o -37570 -00834 26 '94252 o -70681 -11828 o -18919 -42466 o -01919 30 o -92621 o -61993 0-12991 o -10497 o -45370 0-02914 Oct. 4 o -90680 o -53095 0-14109 0-01587 o -46161 o -03773 8 -88377 o -43990 o -15172 +o -07396 o -44764 '04453 12 '85647 o -34673 0-16162 -16005 '41133 o -04910 16 '82431 0-25157 o -17060 o -23743 -35283 '05103 20 o -78639 o -15474 0-17837 -30045 o -27322 o -04987 24 0'74170 + -05655 -18461 -34263 o -17469 '04529 28 -68924 0-04218 -18890 o -35691 o -06262 o -03704 Nov. 1 o -62786 0-14032 o -19075 -33638 + -05541 02520 5 o -55672 -23622 0-18961 o -27643 0-16651 0-01046 9 o -47529 o -32763 -18496 -17853 -25419 +o -00567 13 '38379 -41220 0-17640 + -05316 -30238 o -02091 17 -28356 -48727 '16380 -08074 -30252 -03283 21 0'17673 -55104 o -14740 o -20296 -25748 o -03987 25 + -06600 o -60262 o -12774 o -29920 0-17877 o -04176 29 -04613 -64230 + 0-10554 -36320 + -08033 +o -03910 at its appearance in the Years 1835 fy 1836. 215 TABLE III. continued. HELIOCENTRIC CO-ORDINATES OF Date. THE COMET. MERCURY. 1835. X y z *i 2/1 2l Nov. 29 '04613 -64230 + -10554 -36320 + -08033 +o -03910 Dec. 3 o -15751 o -67104 -08152 o -39459 '02564 -03290 7 o -26672 o -69032 -05635 o -39616 0-12991 -02421 11 -37289 o -70155 -03050 0-37199 -22590 o -01392 15 o -47555 0'706l7 +o -00437 '32650 '30902 + 0-00282 19 '57458 o -70539 -02181 0-26397 0-37615 -00842 23 o -66999 o -70013 o -04786 -18856 -42497 o -01927 27 o -76196 o -69123 o -07366 -10429 -45385 o -02920 31 -85065 o -67934 o -09915 -01516 o -46162 o -03778 1836. Jan. 4 o -93620 -66500 0-12427 + o -07465 o -44744 o -04457 8 1 '01892 -64859 o -14902 o -16070 o -41096 '04913 12 1 -09896 '63046 0-17338 o -23799 -35231 -05102 16 1 -17652 o -61089 o -19735 -30087 o -27253 -04986 20 1 -25176 o -59015 o -22092 '34285 o -17408 '04524 24 1 -32483 -56837 0-24412 -35689 o -06171 o -03696 28 1 -39589 o -54573 o -26696 o -33606 + -05632 -02510 Feb. 1 1 '46508 -52241 -28942 '27585 0-16731 -01034 5 1 -53250 -49838 -31154 0-17764 o -25472 + -00580 9 1 '59834 '47385 -33334 + -05213 '30257 -02102 13 1 -66253 -44885 -35480 -08175 '30232 o -03290 17 1 -72536 -42347 o -37597 -20380 o -25699 o -03990 21 1 '78682 -397/6 -39683 -29982 o -17807 o -04176 25 l -84697 o -37174 o -41740 '36356 + o -07954 o -03906 09 1 -90594 o -34557 o -43770 o -39471 o -02646 -03285 Mar. 4 1 -96372 0-31911 o -45774 o -39606 -13068 -02413 8 2 '02041 o -29241 o -47753 0-37173 '22658 '01383 12 2 -07601 -26564 o -49705 -32608 o -30960 + o -00275 16 2-13074 -23875 -51636 -26344 -37658 -00850 20 2 -18443 o -21175 -53544 -J8794 -42526 o -01934 24 2 -23723 -18459 -55428 0-10363 o -45398 o -02927 28 2 -28929 o -15747 o -57293 -01448 o -46159 -03785 Apr. 1 2 '34045 o -13017 o -59137 4-0 -07533 o -44726 '04462 216 On the Elements of the Orbit of Halle ys Comet, TABLE III. continued. Date. HELIOCENTRIC CO-ORDINATES OF VENUS. THE EARTH. 1835. X 2 y* ** r 3 y* *3 Aug. 1 5 9 13 17 + '04533 '03582 -11652 o -19574 o -27247 +o -71820 71834 o 70932 o -69129 o -66447 + -00829 o -01293 0-01742 -02168 -02567 +o -63109 -68234 73053 o 77537 o -81672 '79458 o 75020 -/0243 '65149 -59758 * 21 25 29 Sep. 2 6 o -34572 -41456 -47812 o -53559 '58622 o -62917 -58584 -53504 o -47742 0-41371 o -02934 o -03263 -03551 o -03793 '03986 -85436 -88806 o -91768 '94303 '96405 o -54094 -48178 -42041 -35/12 o -29220 ,np r!.^ 10 14 18 22 26 -62938 -66452 o -69120 070910 0'71802 o -34472 o -27134 o -19451 -11521 + -03446 '04128 -04218 '04255 -04239 0-04167 '98064 o -99270 1 -00010 1 -00283 1 -00082 o -22593 0-15862 o -09056 o -02206 + 0-04657 - 30 Oct. 4 8 12 16 o -71733 '70856 o -69034 '66342 0-62817 o -04673 o -12734 -20634 -282/5 o -35560 '04043 -03868 -03644 o -03373 -03061 o -99112 o -98272 o -96670 o -94609 o -92098 0-11497 -18278 0-24971 '31548 o -379/6 ~ * 20 24 28 Nov. 1 5 '58505 -53461 o -47750 '41443 0'34621 -42398 -48705 -54405 o -594-28 0-63714 o -02710 -02325 o -01912 o -01476 '01020 -89140 -85755 o -81956 o 77764 073194 -44223 -50259 -56050 0-61569 o -66787 > -*>;* 1 9 13 17 21 25 o -27370 o '19779 o -11944 o -03962 + -04068 o -67208 o -69869 071667 '72583 o 72606 -00551 +o -00075 -00402 '00873 '01333 o -68270 0-63010 o -57443 -51591 -45486 o -71682 o 76229 -80406 '84186 o -87553 i " 29 Dec. 3 7 11 15 -12048 -19880 o -27469 o -34722 '41549 o 71735 -69983 o -67373 o -63937 -59/18 0-01777 -02199 -02594 -02958 '03285 '39158 -32638 o -19150 '90483 o -92967 '96554 r ~*" ""Hi 19 +o 4/867 o -54768 o -03572 + 0-05274 + '98229 *. ^ . at its appearance in the Years 1835 $ 1836. 217 TABLE III. continued. Date. HELIOCENTRIC CO-ORDINATES OF VENUS. THE EARTH. 1835. ^ 2 2/2 *2 #3 2/3 *3 Dec. 1 ( J + o --P7867 o -54768 o -03572 + o -05274 + '98229 _ 23 o -53598 o -49147 -03814 - - ^Vfi 27 -58672 o -42923 -04011 o -08707 '97942 - 31 o -63027 o -36173 '04159 - - J 1836. Jan. 4 o -66610 -28980 '04257 -22505 0-95711 - - 8 o -69376 -21432 -04300 i," ^ L'-'j. ' _ _ 12 o -71290 o -13621 -04291 -35860 0*91584 _ 16 o 72326 0-05641 -04229 - - , . 20 o -72470 + 0-02408 '04115 0-48511 0-85631 - 28 70084 -18316 o -03739 o -60191 o -779/6 - Feb. 5 '64230 -33320 o -03176 o 70677 -68788 _ _ 13 o -55190 o -46670 o -02457 079781 0-58241 _ 21 -43399 o -57690 0-01613 '87315 -46544 _ 29 o -29435 -65822 o -00690 '93141 -33944 _ Mar. 8 + -13990 o -70643 +o -00268 o -97165 0-20691 ' "ri ' W * 16 o -02161 071899 '01214 o -99316 4-0 -07032 _ _ 24 -18203 o -69510 o -02097 o -99561 o -06767 - Apr. 1 0-33317 +o -63592 + '02873 0-97911 '20428 - - *''-* S t\ : :i?;;;V& [-^i8$ff b* CS Date. MARS. JUPITER. 1835. #4 y4 m *"\ #5 2/3 2 5 Aug. 5 -54181 -48934 +o -02664 + '15810 + 5 -13050 '02150 13 49982 '58556 -02356 - - -'*'. 21 45104 0-67914 '02037 4-0-03617 5 '13854 0-01868 29 39553 o 76959 o -01706 _ - - o \ Sep. 6 33355 -85641 o -01369 -08574 5 -14375 o -01601 14 26523 0-93918 o -01027 . _ _ _ 22 19078 1 -01744 o -00679 o -20774 5 -14600 -01318 30 11045 1 -09064 + -00331 " : - vl" SS^ - Oct. 8 1 '02452 1 -15838 '00022 o -32959 5-14553 '01050 16 '93338 1 -22017 o -00375 - - . - . - ; 24 o -83739 1 -27562 o -00728 -45124 + 5 '14209 o -00766 NAUTICAL ALMANAC, 1839. APPENDIX. 218 On the Elements of the Orbit of Halley's Comet, TABLE III. continued. Date. HELIOCENTRIC CO-ORDINATES OF MARS. JUPITER. 1835. X 4 y* *4 *5 y* 2 5 Oct. 24 o -83739 1 -27562 o -00728 '45124 + 5-14209 o -00766 Nov. 1 o -73690 1 -32422 0-01076 . - ^.*. . - - 5 -68512 34586 '01246 i*. _ - 9 0-63241 36565 '01414 o -57261 5 -13594 o -00496 13 0-57881 38354 '01582 - - - - 17 '52441 39949 '01748 o -63317 5-13181 -00353 21 o -46928 41346 o -01912 - - - 25 0-41348 45241 o -02072 o -69365 5 12696 -00211 29 o -35706 43526 '02230 T ;.;' _ - Dec. 3 0-30011 44301 '02384 o -75409 5-12135 o -00075 7 o -24274 44867 '02536 _ _ _ - 11 -18500 45218 '02683 '81442 5 -11505 +o -00060 15 o -12697 45347 '02824 . - - 19 o -06375 45255 o -02961 - 't ! < - 23 '01043 44941 o -03095 - t' s - 27 +o -04790 44401 -03224 o -93457 5 -10047 o -00347 31 0-10618 43632 -03348 - - - 1836. Jan. 4 -16428 42636 o -03467 - - *'?/ 8 -22210 41414 '03580 _ _ - 12 o -27955 39965 '03688 1 -05436 5 -08323 o -00619 20 -39305 36386 '03886 _ _ _ - 28 -50394 31899 '04055 1 47355 5 -06302 -00892 Feb. 5 0-61145 1 '26532 '04199 *V f - - 13 o -71474 1 -20298 0-04316 1 '29205 5 -04011 0-01181 21 -81319 1 -13235 -04401 - - - - 29 o -90590 1 -05385 '04452 1 '41000 5 -01453 0-01455 Mar. 8 o -99222 o -96792 o -04477 _ - - 16 1 -07152 '87512 '04469 1 -52700 4 '98632 o -01729 24 1 -14319 o -77609 '04429 - - l - Apr. 1 + 1 -20670 o -67151 -04356 1 -64327 + 4-95541 + '02005 '?* >' . ' "^ A ' at its appearance in the Years 1835 Sf 1836. 219 TABLE III. continued. Date. HELIOCENTRIC CO-ORDINATES OF SATURN. THE GEORGIAN. 1835. X 6 2/6 2<> x 7 y? 2 7 Aug. 5 -8 -89774 3 -88947 + -42209 + 17 -0573 10 -4973 o -26210 21 8 '86645 3 -97109 o -42219 17 '0899 10 -4472 '26231 Sep. 6 8 '83446 4 -05257 '42224 17 -1214 10 -3966 -26251 22 8 '80195 4 -13352 -42226 17*1538 10 -3452 o -26272 Oct. 8 8 76859 4 -21415 -42227 17-1854 10 -2941 o -26292 24 8 73474 4 -29447 -42222 17-2171 10 -2431 -26313 Nov. 1 8 71738 4 -33460 "42218 > ! - 9 8 -69981 4 -37462 -42213 17 -2484 10-1920 -26334 17 8 '68210 4 '41440 o -42206 U V - ! ; 25 8 '66423 4 -45410 o -42199 17-2795 10*1405 '26354 Dec. 1 1 8 -62800 4 -53367 -42180 17 -3101 10 -0890 o -26374 27 8 -59112 4 -61233 o -42167 17-3412 10 -0370 o -26395 1836. Jan. 12 8 '55342 4 -69105 -42142 17 -3724 9 '986o o -26416 28 8 -51530 4 76947 '42115 17-4028 9 *9344 o -26436 Feb. 13 8 -47618 4-84719 '42086 17 -4333 9 '8828 o -26457 29 8 -43665 4 -92436 '42057 17 -4639 9 *8308 o -26478 Mar. 16 8 -39615 5 -00138 '42018 17 -4936 9 7787 '26488 Apr. 1 8 '35526 -5 -07797 + -41981 4.17-5235 9 7268 -26509 i* , q 2 220 On the Elements of the Orbit of Halley's Comet, TABLE IV. Containing, for Greenwich Mean Noon of each fourth day, from Aug. 1, 1835, to April 1, 1836, the united Effects (A) of the attractions of the disturbing Planets upon the Comet in the direction of the co-ordinate x, expressed in 10,000,000,000th parts of an unit, and distinguishing the separate Effect of each Planet. Date. Mercury. Venus. Earth. Mars. Jupiter. Saturn. Georgian A. 1835. Aug. 1 + 36848 + 11611 + 17620 1116 + 196320 8558 + 97 + 252822 5 42145 6705 19032 1104 190031 8398 90 248501 9 41413 + 1537 20367 1091 183562 8232 83 23/639 13 30642 3781 2l6l6 1077 176930 8061 76 216345 17 + 10536 9111 22773 1061 170155 7883 69 185478 21 11180 14318 23831 1042 163284 7700 62 152937 25 26320 19277 24780 1021 156341 7511 55 127047 29 32794 23886 25610 998 149332 7314 48 109998 Sep. 2 33032 28053 26301 972 142265 7109 41 99441 6 30023 31713 26831 943 135164 6894 33 92455 10 25728 34806 27158 911 128052 6671 25 87H9 14 21124 37288 27207 876 120921 643/ 17 82420 18 16592 39123 26818 837 113761 6190 9 77846 22 12213 40286 2o62/ 795 106585 5930 + 1 72989 26 7923 40762 22652 748 99401 5657 ~ 7 66956 30 3584 40530 + 14783 696 92202 5367 15 56793 Oct. 4 + 996 39585 10274 639 84976 5056 23 + 30395 8 6069 37916 110218 575 77723 4723 30 69670 12 11984 35512 356598 503 70435 4368 37 314599 16 19294 32346 185594 421 63116 3986 43 139980 20 29065 28372 41067 327 55773 3571 50 + 11451 24 43494 23494 2076 219 48367 3118 58 62896 28 61638 17522 + 9898 - 93 40863 2624 72 92088 Nov. 1 62110 10080 14024 + 57 33326 2086 88 97263 5 49829 - 397 15260 239 25834 1500 101 89164 9 34105 + 13233 15201 459 18374 866 108 80398 13 + 12161 34958 14462 724 10939 188 102 72954 17 10130 75992 13318 1026 + 3631 + 517 90 84264 21 25236 163607 11907 1329 3453 1239 75 149318 25 31375 + 95881 10307 1526 10273 1962 61 + 67967 29 31111 379845 8563 1404 16801 2668 52 415174 Dec. 3 27607 159455 6708 + 721 23033 3354 44 199356 7 23508 64310 4761 - 487 28985 4011 36 108554 11 22283 24629 2742 1721 34681 4635 28 75965 15 27377 3809 + 662 2466 40156 5217 19 67948 19 29934 + 9163 1466 2652 45427 + 5760 10 64566 at its appearance in the Years 1835 $ 1836. 221 TABLE IV. continued. Date. Mercury. Venus. Earth. Mars. Jupiter. Saturn. Georgian. A. 1835. Dec. 19 29934 + 9163 - 1466 2652 45427 + 5760 10 64566 23 23121 18202 3630 2486 50516 6266 1 55286 27 14508 24939 5822 2172 55457 6737 + 8 46275 31 7112 30130 8033 1825 60285 7174 17 39934 1836. Jan. 4 583 34157 10251 1495 65003 7577 26 35572 8 + 5756 37230 12468 1198 69614 7948 35 32311 12 12401 39462 14686 935 74141 8288 44 29567 16 19643 40921 16909 702 78607 8598 52 27004 20 27431 41656 19129 495 83013 8879 60 24611 24 3500/ 41697 21339 309 87360 9132 68 23104 28 40235 41074 23544 140 91660 9359 76 24600 Feb. 1 39220 39809 25748 + H 95926 9562 84 32985 5 28021 37932 27954 157 100160 9740 91 52173 9 + 7558 35473 30160 290 104363 9894 99 81209 13 14278 32469 32359 413 108544 10024 106 112169 17 29373 28959 34531 529 112709 10132 113 136880 21 35787 24988 36635 638 116860 10217 120 153319 25 35984 20606 38612 741 120999 10281 127 163840 29 32924 15869 40369 838 125129 10323 134 171258 Mar. 4 28534 10837 41812 930 129256 10345 141 177349 8 23802 5574 42839 1017 133382 10347 147 182938 12 19136 + 149 43370 1098 137508 10229 153 188385 16 14651 5367 43386 1174 141637 10293 159 193415 20 10313 10901 42902 1245 145769 10239 165 198236 24 6007 16378 41990 1312 149910 10167 171 202635 28 1576 21724 40748 1374 154070 10078 177 206489 Apr. 1 + 3162 26863 39257 + 1430 158248 + 9972 + 182 209622 (, ~ ' - - i * .? I 222 On the Elements of the Orlit of Hatteys Comet, TABLE V. Containing, for Greenwich Mean Noon of each fourth day, from August 1, 1835, to April 1, 1836, the united Effects (B) of the attractions of the disturbing Planets upon the Comet in the direction of the co-ordinate y, expressed in 10,000,000,000th parts of an unit, and distinguishing the separate Effect of each Planet. Date. Mercury. Venus. Earth. Mars. Jupiter. Saturn. Georgian B. 1835. Aug. 1 5216 + 57349 17205 - 171 406607 1181 + 100 372931 5 + 8207 56610 15626 214 374253 1251 101 326426 9 25951 55158 13876 257 343563 1320 102 277805 13 43508 53098 11937 299 314472 1389 103 231388 17 52882 50506 9784 341 286878 1458 103 194970 21 49407 47440 7386 383 260718 1526 104 173062 25 36660 43938 4688 424 235887 1594 104 161891 29 21620 40039 1616 464 212329 1662 104 154308 Sep. 2 + 8683 35776 + 1945 504 189992 1729 104 145717 6 988 31188 6180 543 168775 1794 103 134629 10 7785 26320 11395 582 148579 1858 103 120986 14 12466 21226 18102 617 129376 1921 102 104950 18 15689 15966 27247 651 111145 1981 101 86152 <22 17922 10602 40670 684 93796 2038 100 63068 26 19462 + 5207 62251 714 77242 2094 99 31955 30 20468 150 101095 741 61494 2147 97 + 16192 Oct. 4 20975 5395 179393 765 46574 2194 94 103584 8 20893 10450 322598 785 32398 2235 91 255928 12 19957 15237 + 142675 799 18893 2269 87 + 85607 16 17648 19669 270096 804 6133 2294 82 316562 20 13162 23651 169564 800 + 5794 2308 77 203614 24 6516 27069 88291 784 16937 2306 72 107957 28 4848 29767 47178 747 27331 2283 70 57422 Nov. 1 - 6950 31491 24781 684 36851 2234 69 29220 5 + 11045 31769 11301 581 45367 2154 66 + 10673 9 32602 29539 2483 415 52783 2034 6l 50975 13 44395 21919 + 3658 154 59022 1868 47 83181 17 42131 + 1103 8144 + 256 64012 1652 29 114023 21 29800 87166 11528 886 67726 1386 + 11 195731 25 14477 407564 14142 1803 70263 1074 - 6 507169 29 + 395 + 128198 16181 2975 71763 720 19 218773 Dec. 3 11754 31315 17773 4115 72380 330 29 50840 7 23274 46031 18996 4662 72280 + 90 38 26685 11 35285 45337 19911 4269 71616 531 47 15658 15 42472 42287 20547 3216 70524 986 56 10458 19 36628 38508 + 20932 + 2034 + 69034 + 1454 - 64 + 18164 at its appearance in the Years 1835 fy 1836. 223 TABLE V. continued. Date. Mercury. Venus. Earth. Mars. Jupiter. Saturn. Georgian. B. 1835. Dec. 19 36628 38598 + 20932 + 2034 + 69034 + 1454 - 64 + 18164 23 28757 34561 21077 1034 67152 1936 72 27809 27 25462 30235 20999 + 288 65009 2426 79 32946 31 24555 25650 20706 244 62721 2919 86 35811 1836. Jan. 4 24285 20837 20205 619 60267 3416 93 38054 8 23845 15830 19502 884 57617 3917 99 40378 12 22682 10679 18605 1073 54823 4418 105 43307 16 20136 5431 17524 1208 51927 4919 110 47485 20 15257 140 16268 1305 48925 5419 115 53795 24 6764 + 5132 14854 1372 45807 5918 120 63455 28 + 6499 10328 13298 1418 42593 6416 124 77592 Feb. 1 24053 15388 11624 1447 39302 6911 128 95703 5 41413 20250 9862 1462 35930 7403 132 113264 9 50646 24855 8052 1466 32473 7891 136 1*22315 13 47144 29143 6249 1459 28938 8375 140 118250 17 34506 33058 4513 1444 25330 8854 144 104673 21 19663 36547 2916 1422 21650 9327 147 88534 25 + 6965 39566 1520 1394 17896 9795 150 74198 29 2462 42071 + 373 1358 14072 10256 153 62799 Mar. 4 9054 44027 506 1317 10180 10710 157 53883 8 13600 45405 1156 1271 6220 HI 56 160 46594 12 16773 46185 1643 1220 + 2193 11595 163 40174 16 19047 46354 2078 1165 1904 12025 166 34019 20 20714 45911 2582 1106 6074 12446 169 27712 24 21939 44862 3215 1043 10307 12859 171 21046 28 22788 43225 4039 977 14604 13263 173 13907 Apr. 1 23220 + 41025 5116 908 18965 + 13657 -175 + 6298 -'- "VI. LJi'S + ;U& + *\-''ilIj ~"~ i'vU ~-j Ci -'.: J;c,-i Jk *U'-.4 tc8 -" ' - 224 On the Elements of the Orbit of Halley's Comet, TABLE VI Containing, for Greenwich Mean Noon of each fourth day, from August 1, 1835, to April 1, 1836, the united Effects (C) of the attractions of the disturbing Planets upon the Comet in the direction of the co-ordinate z, expressed in 10,000,000,000th parts of an unit, and distinguishing the separate Effect of each Planet. Date. Mercury. Venus. Earth. Mars. Jupiter. Saturn. Georgian. C. 1835. Aug. 1 3800 - 57 - 98 + 15 - 9965 + 383 4 13526 5 3143 + 342 89 16 6842 400 3 9319 9 - 1577 740 74 16 4037 417 2 - 4517 13 + 877 1123 54 16 1535 435 1 + 861 17 3484 1482 24 16 + 679 453 6090 21 5149 1810 + 19 16 2639 472 4 1 10106 25 5441 2104 84 17 4378 491 2 12517 29 4761 2361 181 18 5906 509 3 13739 Sep. 2 3701 2578 332 18 7231 527 4 14391 6 2629 2758 571 19 8379 545 5 14906 10 1686 2899 966 20 9377 563 6 15517 14 896 3004 1649 21 10228 581 7 16386 18 + 242 3073 2902 22 10933 599 8 17779 22 307 3109 5394 24 11512 616 q U 20357 26 776 3113 10918 26 11982 633 10 25906 30 1182 3092 25176 28 12341 649 11 40115 Oct. 4 1525 3051 70609 32 12585 664 12 85428 8 1783 2998 251704 37 12726 677 13 266372 12 1871 2944 691560 43 12776 689 14 706155 16 1550 2907 373844 50 12726 699 15 388691 20 113 2913 113050 59 12569 704 16 129198 24 + 4445 3006 42511 72 12306 704 16 63060 28 13336 3266 19803 89 11938 699 16 49147 Nov. 1 12114 3847 10738 113 11460 6s6 16 38974 5 5105 5084 6427 147 10869 663 16 28311 9 3783 7806 4127 192 10159 629 17 26713 13 5027 14496 2785 255 9329 579 16 32487 17 6143 34615 1945 342 8392 514 15 51966 21 6192 119356 1387 457 7364 431 13 135200 25 5417 518654 998 595 6264 333 11 532272 29 4348 285750 711 721 5111 221 Q / 296871 Dec. 3 3333 48633 489 763 3920 + 97 i 57242 7 2471 10795 311 656 2706 38 4 16905 11 1591 + 2015 158 426 1477 180 1 + 6489 15 + 254 84 + 22 182 + 240 328 + 1 - 470 19 114C 2018 105 + 4 1007 481 1 4748 at its appearance in the Years 1835 fy 1836. 225 TABLE VI. continued. Date. Mercury. Venus. Earth. Mars. Jupiter. Saturn. Georgian. c. 1835. Dec. 19 1140 2018 105 + * 1007 481 1 4748 23 1768 2594 229 101 2270 639 3 7604 27 2057 2913 354 154 3543 800 5 9826 31 2341 3100 485 176 4824 963 7 11896 1836. Jan. 4 2676 3208 626 183 6115 1127 9 13944 8 3051 326l 781 180 7422 1293 11 15999 12 3442 3270 955 175 8744 1460 12 18058 16 3803 3238 1153 168 10083 1628 13 20086 20 4039 3178 1381 162 11439 1796 15 22010 24 3966 3087 1645 156 12816 1964 16 23650 28 3295 2957 1951 150 14215 2132 18 24718 Feb. 1 1720 2804 2305 144 15637 2300 19 24929 5 + 725 2625 2715 139 17083 2467 21 24325 9 3287 2423 3182 135 18556 2634 22 23665 13 4868 2201 3707 132 20057 2800 23 24052 17 5056 1961 4280 129 21588 2965 24 25891 21 4279 1709 4882 126 23151 3129 26 28744 25 3146 1448 5483 123 24747 3292 27 31974 29 2040 1183 6034 121 26377 3453 28 35156 Mar. 4 1105 918 6488 118 28043 3612 29 38103 8 + 351 657 6792 116 29747 3770 30 40761 12 260 406 690/ 114 31490 3926 31 43134 16 775 - 169 6825 112 33275 4079 32 45267 20 1233 + 48 6558 110 35104 4230 33 47220 24 1661 242 6144 108 36977 4379 34 49061 28 2080 410 5634 106 38896 4525 34 50865 Apr. 1 2500 + 549 5076 105 40863 4669 K i 35 52699 "T ' 226 On the Elements of the Orbit of Halley's Comet, TABLE VII. Containing, for Greenwich Mean Noon of each fourth day, from August 1, 1835, to April 1, 1836, the Values of A', B', C', expressed in 10,000,000,000th parts of an unit. Date. A' B' C' Date. A' B' C' 1835. 1835. Aug. 1 400192 + 379032 + 141231 Dec. 7 + 11485 + 101222 f 47929 5 301357 358155 128032 11 17539 69220 27928 9 211518 329654 112257 15 24926 59426 18386 13 141858 292643 93706 17 102748 252128 74645 19 24389 59864 14810 23 17936 58438 11451 21 90639 217317 58853 27 13211 55640 7974 25 89146 193228 48127 31 10821 53820 4916 29 84787 177804 41372 1836. Sep. 2 73714 166523 36611 Jan. 4 9730 53215 2265 6 57437 156071 32437 10 38417 144762 28140 8 9118 53611 + 103 14 - 18463 131718 23336 12 8320 55031 2240 18 + 1635 116138 17587 16 6727 57842 4084 22 22026 96485 + 9889 20 3923 62825 5414 26 43585 69390 2335 24 + 317 71329 5668 30 67851 + 26861 26810 28 1407 84977 + 3844 Oct. 4 94611 50570 91816 Feb. 1 + 5544 104188 1213 8 + 91421 182278 315760 5 31087 125261 9655 12 125628 1588 766170 9 79727 139831 19132 16 128719 + 356292 349965 13 141938 141288 25805 20 + 544 226084 84652 17 201580 131390 27870 24 52187 119597 25473 21 250151 116780 26453 28 75176 54565 13733 25 288374 102408 23510 Nov. 1 72601 + 8246 7670 29 320097 90076 20348 5 52487 44330 6502 Mar. 4 348516 79732 17511 9 + 26453 87584 14205 8 375450 70725 15107 13 557 112055 27186 12 401858 62406 13092 17 23152 137530 48286 16 427372 54192 11245 21 61543 229148 125518 20 452446 45735 9491 25 233150 262744 578345 24 476649 36849 7676 29 - 90035 + 329951 424816 28 499672 27466 5678 Dec. 3 + 1952 181003 113288 Apr. 1 + 520954 + 17609 3389 7 + 11485 + 101222 - 47929 - at its appearance in the Years 1835 $ 1836. 227 TABLE VIII. Containing the Variations of the Elements of the Comet's Orbit for each interval of four days, between the Noon of July 30, 1835, and the Noon of April 3, 1836, Greenwich Mean Time; the tabular date being the middle of each interval. * # * The figure in a parenthesis, at the head of a column, indicates the number of cyphers to be prefixed to all the values in that column. Date. M M M M M M 1835. 0'(2) 0'(5) // // // a Aug. 1 16336 26591 +o -11876 o -37360 1 -60324 0-91704 5 14500 23503 '08438 -32982 1 -47658 o -86797 9 12507 20180 '05353 -28125 1 -32495 -80042 13 10549 16974 o -02757 o -22796 1 '15008 o -70786 17 08993 14511 + '00832 o -17603 o -97468 o -59770 21 08075 13152 -00420 '13429 0-83170 o -49304 25 07645 12589 -01224 o -10604 o -73334 '41255 29 07377 12253 -01807 -08781 o -66679 o -35717 Sep. 2 07047 11770 o -02266 o -07467 o -61397 -31813 6 06578 11022 -02595 o -06337 -56339 -28726 10 05958 09999 -02758 -05248 -51025 o -26016 14 05188 08707 o -02704 -04139 _0 '45250 o -23475 18 04243 07101 '02348 o -02952 -38839 o -21037 22 03028 05018 o -01492 -01563 0-31387 -18683 26 01341 02101 +o -00392 + -00345 o -21975 -16348 30 + 01292 + 02486 0"'04942 o -03677 -08391 '13809 Oct. 4 05904 10548 0-18382 0-11572 + -14815 o -09948 8 + 12478 + 22003 o -679/8 -36132 -53807 + 0-01473 12 05187 09472 1 -75710 '78360 + 0*13846 '35552 16 25208 44683 o -34717 0-31333 -82022 o -23627 20 13279 23452 '21425 -06448 '54292 + -01356 24 05189 09083 o -06673 -01583 '32026 '10245 28 00389 00545 -03681 -00652 -21084 o -19390 Nov. 1 + 02334 + 04282 o -02076 -00247 o -13961 -23658 5 05154 09287 o -01749 o -00107 o -05269 o -26766 9 07611 13666 . o -03728 + "00005 + 0-01254 -30519 13 09168 16452 -06805 -00426 -04645 -33634 17 11410 20483 '11223 -01516 -04872 o -42751 21 19649 35284 -26254 -05820 -02358 079611 25 + 27384 + 49289 1 -04830 -34892 o -29122 0-85178 29 21037 37484 +o '63619 '31053 +o -69732 + 1-57194 228 On the Elements of the Orbit of Halleys Comet, TABLE VIII. continued. Date. [] M M M W [] 1835. 0'(2) "(5) // // // ii Nov. 29 21037 37484 +o -63619 -31053 +o -69732 + 1 ^7194 Dec. 3 12683 22616 '13105 -09588 -33595 -86342 7 07103 12645 '03832 '04551 -20249 '49779 11 04997 08886 o -01209 o -02910 o -14724 o -35496 15 04475 07954 + '00114 -02068 -13443 -32039 19 04221 07474 -00458 o -01775 o -15017 -32548 23 03644 06411 o -00778 -01448 o -16087 o -31196 27 03121 05455 '00833 '01056 0-16190 o -29140 31 02779 04823 o -00692 o -00678 0-16363 o -27892 1836. Jan. 4 02567 04425 -00399 -00323 o -16760 o -27406 8 02430 04162 + -00022 + -00015 0-17396 o -27479 12 02341 03976 -00551 -00339 -18317 '28028 16 02286 03845 -01144 o -00633 o -19665 0-29149 20 02277 03784 o -01697 -00858 o -21716 -31165 24 02366 03877 o -01963 o -00916 o -24971 o -34794 28 02661 04309 + 0-01456 + '00633 0-30101 -41156 Feb. 1 03318 05359 -00498 -00203 o -37505 o -51292 5 04418 07193 -04268 0-01639 o -46219 -64562 9 05766 09518 o -09049 o -03292 -53426 o -77337 13 06940 11615 o -12991 o -04496 -56422 -85163 17 07661 12974 -14868 0-04911 -55240 o -86922 21 07978 13636 -14895 o -04711 o -51949 -84892 25 08070 13894 "13924 -04227 -48343 -81621 29 08077 13986 -12638 o -03691 "45205 '78468 Mar. 4 08065 14032 o -11374 -03203 o -42626 o 75796 8 08053 14070 -10236 -02784 '40421 o -73495 12 08044 14113 o -09234 -02430 '38386 o -71378 16 08018 14129 -08239 -02101 -36283 o -69122 20 07978 14123 o -07211 '01784 '34001 o -66621 24 07914 14083 o -06037 -01451 '31449 o -63751 28 07822 14001 o -04616 o -01078 -28596 -60464 Apr. 1 07698 13869 '02844 o -00647 + -25435 +o -56728 at its appearance in the Years 1835 fy 1836. 229 TABLE IX. Containing the total amount of Variation of each of the Elements of the Comet's Orbit, on every fourth day, commencing at the Noon of July 30, 1835, and ending at Noon of April 3, 1836, Greenwich Mean Time. *** The figures in the parentheses indicate the number of cyphers between the decimal point and the first significant figure. Date. $a Se Zv ft TJ Se 1835. ti // n ii July 30 '0000000 o -oooooooo '00 '00 '00 o -oo Aug. 3 '(2) 16329 '(5) 266 + 0'13 0-37 1 -60 o -92 7 30822 501 '23 0-70 3 '08 i 79 11 43330 703 0'30 0-98 4 -40 2 -58 15 53896 '(5) 873 '34 1 '20 5 '56 3 -29 19 62915 '(4)1018 0'36 1-37 6 '53 3-89 23 71010 1150 o -37 1 '51 7-37 4-39 27 78662 1276 o -37 1-61 8 '10 4 -80 31 86036 1398 '36 170 877 5 -16 Sep. 4 93077 1516 0'35 1*77 9*38 5 -48 8 '(2) 99649 1626 0'34 1 '83 9'95 577 12 '(1)105601 1726 '32 1 '88 10 -46 6-03 16 110782 1813 '31 1-92 10 -91 6-26 20 115014 1884 '30 1-94 11 -30 6-47 24 118022 1934 "30 1'95 n -6l 6-66 28 119324 1954 '32 1 '95 11 '83 6 -82 Oct. 2 H7949 1928 '38 1-91 11 '91 6-96 6 111963 1820 o -59 178 11 76 7-06 10 100495 1619 1 -31 1 '41 11 '25 7-04 14 105780 1715 3 '00 0-66 11 '14 670 18 129657 2138 3'87 '33 11 '91 6-47 22 143096 2376 4 -12 "26 12-46 6 -45 26 148422 2469 4 '20 "24 1278 6-56 30 148898 2476 4 '25 '23 12-99 675 Nov. 3 146560 2433 4'29 '22 13'13 6-98 7 141421 2340 4'32 '22 13 -19 7-25 11 133848 2204 4-37 '22 13 -18 7-56 15 124652 2039 4 '45 '22 13 -13 7*90 19 o -(1)112992 1830 4 '58 '23 13-09 8 -34 23 '(2) 93364 1477 4 '88 '30 13'05 9'12 27 0'(2) 68320 '(4)1027 + 5'39 0'63 1275 -9'87 230 On the Elements of the Orbit of Halleys Comet, TABLE IX continued. Date. Sa I 1 } h SCT *e 1835. Nov. 27 '(2) 68320 '(4)1027 + 5 // '89 o"-63 12 75 II -9-87 Dec. 1 86991 1359 6 '54 o -93 12 -09 8 '43 5 0'(2) 99790 1587 670 1 '03 11 75 7-55 9 '(1)107038 1716 6-75 1-07 11 '54 7 -05 13 112101 1806 678 1 '10 11 '39 6-69 17 116587 1886 679 1 -12 11 '26 6-37 21 120795 1961 6 '80 1 '13 11 '11 6-04 25 124441 2025 6'80 1 '15 10-95 573 29 127570 2079 6'81 1 '15 1079 5 '44 1836. Jan. 2 130354 2128 6'81 1-16 10 -62 5 '16 6 132924 2172 6'82 1-16 10 '46 4'89 10 135356 2214 6-84 1-16 10 '28 4 '6l 14 137698 2253 6'85 1 '15 10-10 4 '33 18 139986 2292 6-88 1 -14 9*91 4 -04 22 142267 2330 6'91 1 -13 9-69 3 73 26 144642 2369 6'94 1 '12 9 '44 3 '38 30 147318 2412 6-97 1 -11 9'14 2-97 Feb. 3 150654 2466 6 -98 1 -11 8 76 2-46 7 155082 2538 6-94 1 -12 8 '30 1 -81 11 160841 2633 6-87 1 -15 777 1 '04 15 167762 2749 675 1-19 7-21 0'19 19 175406 2879 6 -61 1 -24 6-66 +o -67 23 183375 3015 6-48 1 '28 6'14 1 -52 27 191441 3154 6'35 1 '32 5 '65 2 '34 Mar. 2 199517 3293 6 '24 1 '36 5'20 3-12 6 207582 3434 6-14 1 -38 478 3'88 10 215635 3574 6-05 1 -41 4-37 4 '61 14 223678 3716 5 -97 1 -43 3'99 5-33 18 231695 3857 5'90 1 -45 3 '63 6'02 22 239672 3998 5 '84 1 '46 3-29 6'68 26 247585 4139 579 1 '48 2*98 7-32 30 255406 4279 5'76 1 '48 2-69 7-93 Apr. 3 '(1)263103 '(4)4418 + 574 -1-49 2-44 + 8'49 at its appearance in the Years 1835 fy 1836. 231 TABLE X. Containing, The Apparent Right Ascension and Declination, and the Logarithm of the True Distance from the Earth, of HALLEY'S Comet, from August 1-5, 1835, to March 31*5, 1836, Mean Time at Greenwich, deduced from approximate Ele- ments of its orbit, on the supposition that those Elements continued invariable during the interval : and the Perturbations in Right Ascension and Declination produced by the disturbing Planets, on the assumption that the approximate Elements represent the actual orbit in which the Comet was moving at Mean Noon at Greenwich on July 30, 1835. Date. Apparent Right Ascension. Pertur- bations. Apparent Declination. Pertur- bations. Log. of True Dist. from the Earth. 1835. Aug. 1 '5 2 '5 3'5 ' 1 // 81 21 56'0 81 33 55 '2 81 45 55 '5 n *2 0-3 0'3 o / // + 21 55 40 '8 21 59 49-1 22 4 1 -0 // o-o o-o o-o '40743 -40252 o -39750 4'5 81 57 56 '7 5'5 82 9 58 '8 6 '5 82 22 2 *1 0-3 0'3 0'4 22 8 16 '8 22 12 36 '7 22 17 1 -0 0*0 o-o o-o o -39239 0-38717 0-38186 7'5 8'5 9'5 82 34 6 *3 82 46 1 1 '8 82 58 18'4 0-4 0-2 O'O 22 21 29 '9 22 26 3 7 22 30 42'6 o-o o -o O'O o -37643 o -37090 -36525 10 '5 11 '5 12'5 83 10 26-3 83 22 35 "7 83 34 46 '4 + 0-1 0*2 0-2 22 35 27-1 22 40 17 '3 22 45 13 '8 o -o o-o o -o o -35949 -35361 o -34760 13-5 14'5 15 '5 83 46 58 '7 83 59 12 '7 84 1 1 28 '6 + 0-3 0*3 0'4 22 50 l6'5 22 55 26'3 23 43 '3 + 0-1 0*1 O'l 0-34147 -33521 -32881 16-5 17-5 18-5 84 23 46-3 84 36 6'0 84 48 277 + 0-4 0-5 0-6 23 6 8 'I 23 11 41 '3 23 17 23-0 + 0'1 0*2 0*2 -32228 0-31560 -30878 19'5 20-5 21 '5 85 51 '8 85 13 18 '4 85 25 47 '6 + 0-6 0-6 0-6 23 23 14 -0 23 29 15 -0 23 35 26 '4 0-3 0-2 + 0-1 0*30180 o -29467 o -23737 22 '5 85 38 19 '4 23 '5 85 50 54 '7 24 -5 36 3 33 '4 + 0-6 0-7 0-7 23 41 48 '9 23 48 23 '6 23 55 10*5 + 0-0 o-i o-i o -27991 o -27226 -26444 25 '5 86 16 15 7 26 '5 86 29 2 '3 27 '5 86 41 53 '4 + 0-7 0-7 0-8 24 211-2 24 9 26 '2 24 16 56 -8 o-o + 0-1 o-i ! ~* -25643 -24823 -23982 28-5 29*5 30 '5 86 54 49 '8 87 7 51 '9 87 21 0'4 + 0-8 0-9 0-9 24 24 43 '6 24 32 48 -1 24 41 11 '5 o-i 0*2 0-3 0-23120 o -22237 0-21330 31*5 87 34 l6'l + I'D + 24 49 55 -3 + 0'3 '20400 On the of lh<> O-rltit of //"//V//.V Cornel, TABLK X. continued. Da*. Apparent Right A0cunvion IVrfm- I'ilhOIIM. A|.|,;.r-nf Declination. Pertwr- bationi. I.M^. -f TII... |)nt. In, in Ih-- K.iilh. 1835. / // jj / n Aug.31 '5 87 :',! 16-1 + '0 + 24 49 55'3 + 0-3 --0100 Sep. 1 '5 87 47 397 o 24 59 0'9 o -:i '19445 2*5 88 1 12-1 1 25 8 29*9 0'3 o -1816:* 3 '5 88 14 54 '8 + '1 25 18 24 '3 + 0'3 '17455 4'5 88 28 48 7 '2 25 28 46 '2 0'3 -16418 88 42 54 '9 2 25 39 37 '0 '2 0-15351 6 :, 88 57 15*4 + '2 25 51 O'l + O'l '14253 7 '5 89 11 51*6 2 26 2 .17 '9 o -o 0-13121 8 '5 89 26 45 '6 3 26 15 33 '4 O'l o -i 195:. 9 '5 89 41 59'3 + '3 26 28 49 '6 O'O '10752 10 T, 89 57 35 '4 4 26 42 50 '8 + '1 o -09509 11 '5 90 13 36'7 5 26 57 41 '0 -2 '08226 1 2 Ti 90 30 6 '5 + '6 27 13 24 '6 + 0'4 o '06900 i :i :, 90 47 8 '2 7 27 30 7 '2 o -:t o (:,., -, 14 '5 91 4 46 '6 8 27 47 55 '1 0'2 o -oi ior, Iff 'ff 91 23 6'7 + 1'9 28 6 54 7 + O'l o -026:50 16 :, 91 42 13 '9 2-0 28 27 14-3 o -o '() I 1 00 17 '5 92 2 15 '0 2*1 28 49 2 '6 - O'l 9 -99509 18 '5 92 23 18 '9 + 2 '3 29 12 30 '3 O'l 9 '97855 19'5 92 45 34 '8 2 '4 29 37 49 '2 0-2 9 '96m 20 '5 93 <) 14 '2 2 '6 30 5 13 '1 0'2 9-9n:ii 21 * 'i 93 34 31 '6 + 2'8 30 34 59*0 0'2 9 '92456 Ol J 94 1 43-5 2-9 31 7 25 '5 o -:t 9 -90-192 23'5 94 31 11'8 31 42 56'7 0'4 9 '88433 24 '5 95 3 21 7 + 8 '3 32 21 58 '2 0-4 9 '86273 25 '5 1)5 38 46 '9 :i -6 33 5 4 -0 0'6 9-84000 26'5 96 18 8 7 3 '8 33 52 53 '4 0*8 9 '8 1606 27 :, 97 2 20 '2 + 4'1 34 46 13 '2 1 '1 1) 79078 28 '5 97 52 32-8 4 ' 1 35 46 4 '5 1 '4 9 -76403 29-5 98 50 19-0 4'4 36 53 37 '6 1'S 9 73566 : \'cur.\ 1835 M l 6 106 5 .V; I 4- 4-5 4 -8 5'1 4:t 16 33-2 43 48 15 -8 44 22 14 '6 - 3'7 3-7 3'8 9 -60269 :r .->!):* 18 9 '58352 4 '25 4 '5 7I 106 45 '7 107 26 58'9 108 11 42 '3 + 5-4 6-7 44 57 2 -8 45 33 14 -0 46 10 51 -2 -3'9 4-1 4'3 9 '*7I70 9 -,6373 9'fj loo 5*0 :> -2.-, 5'5 108 59 39 '4 109 51 10-2 no 46 39-7 + 7*4 7 '9 8*4 46 49 58 '1 47 30 37 -7 48 12 53 -4 4'5 4-7 4-9 9*54331 9 '53288 9 '52229 5 75 6'0 6 '125 111 46 34 '7 112 51 26 '8 113 25 54'8 4- 8*9 9'3 9 '5 48 56 47 '6 49 42 22 '2 50 5 47 '5 S'l 5'4 5*5 9'51156 9'5<< 9 '495 19 6 6 -375 6 -5 114 1 50-6 114 39 20 115 18 27*7 4- 9 '6 \n 9'8 50 29 37'9 50 53 53 '8 51 18 34 7 - 5*7 5 -8 6 '0 9'4i**7 9*494!fl 9 '47854 6 ', ' , 6 ?l 6-875 115 59 20*1 116 42 4'2 117 26 47 o 1- '.> '7 ')<> 9'5 51 43 40 '5 52 !> 10'8 52 35 4 '9 - 6'2 fr-4 6-6 9 '47293 9 -46729 9-4616:5 7'0 7*125 7*w 118 13 35'4 119 2 37 '8 119 54 2-8 9'4 9 '2 8 -9 53 1 22'4 53 28 2'3 53 55 3 '6 - 6-8 7-0 7 '3 9 '45595 9 '45024 91I44H 7 '375 7 '5 7 '625 120 48 O'O 121 44 38*8 122 44 9 '8 + 8'5 8'1 7'6 54 22 24 '8 51 50 4'6 55 18 1 'O -7-5 7-8 8'1 9 '438/8 '.) '4 1 9 '42728 7'7> 7-875 8-0 46 44 '3 124 52 34 -5 126 1 52'6 -H7'i fr'J 5-9 55 46 1 1 '<> 56 14 r*'8 56 43 4 '6 8'5 *<9 '42152 9'4U7I 'J''(> J') ', 11 -1 9 *38/08 9 '38 Ml 9 '3757* 8'875 1 136 3 47 '3 O'l 4-60 20 '8 -11 '3 9 -37019 NAUTICAL AMUHAC 1839, 234 On the Elements of the Orlit of Halley's Comet, TABLE X.-- continued. Date. Apparent Right Ascension. Pertur- bations. Apparent Declination. Pertur- bations. Log. of True Dist. from the Earth. 1835. Oct. 8 '875 9*0 9'125 o / // 136 3 47 '3 137 49 29 "2 139 40 51'9 // o-i 1 '2 2'4 1 II + 60 20 '8 60 26 57 -i 60 52 45 'I ii 11 '3 11 -5 11-7 9-37019 9 '36465 9-35916 9*25 9'375 9'5 141 38 8'3 143 41 29-6 145 51 4-5 - 3-7 5 '2 6-8 61 17 34-1 6l 41 12'6 62 3 27-9 11 '8 11 '9 12 -0 9 -35375 9'34841 9*34316 9'625 9-75 9-875 148 6 58 '2 150 29 12-1 152 57 41-7 - 8-7 10-9 13'2 62 24 6 '6 62 42 54 '3 62 59 36-0 12-0 ll'9 11 '8 9 '33800 9 '33295 9*32801 10 '0 10-125 10'25 155 32 17 '6 158 12 42'3 160 58 32 *1 15-5 17-8 19-9 63 13 55 '9 63 25 38 '5 63 34 27 '9 -11-7 11 '5 11-2 9 '32320 9*31853 9-31401 10-375 10-5 10 '625 163 49 14 '9 166 44 11 '9 169 42 36 -5 21-8 23 '5 24'9 63 40 9*0 63 42 26 '9 63 41 8 -4 1 1 -0 10-7 10-2 9 -30964 9 '30545 9 -30144 10-75 10 '875 11 -0 172 43 34 '9 175 46 9-8 178 49 19*3 26-1 27 '2 28-1 63 36 1 '6 63 26 57 *3 63 13 48 -0 -9'7 9'2 8-6 9 -29764 9 -29404 9 -29066 11-125 11 -25 11 -375 181 52 2 -0 184 53 16'5 187 52 4 '2 -28 '9 29-5 29'9 62 56 29 -0 62 34 58 '9 62 9 18 '8 8-1 7-6 7'2 9-28751 9 -28460 9 -28196 11 '5 11 '625 11 75 190 47 30 '9 193 38 49 'I 196 25 18*4 30-2 30 '2 30'0 6l 39 32 '4 6l 5 46-0 60 28 8 "4 -6-8 6-5 6'2 9 -27957 9 -27746 9 -27562 11 '875 12 '0 12-125 199 6 26 -3 201 41 47-1 204 11 3 '3 -297 29-3 28'8 59 46 50 '7 59 2 5-4 58 14 6'3 -6-0 5-7 5'5 9 -27407 9 -27283 9 ,-2/188 12-25 12 -375 12-5 206 34 4 -0 208 50 44'7 211 1 5-8 28 -3 277 27-1 57 23 8 '4 56 29 27 '3 55 33 19 'I 5-3 5'1 5'0 9-27124 9 -27090 9 -27087 12 '625 12-75 12 -875 213 5 12-0 215 3 10 '7 216 55 13 '2 -26-6 26'2 25 '8 54 34 59 '9 53 34 45 '8 52 32 53 -0 4-8 4'7 4-6 9-27116 9-27175 9 -27264 13'0 13*125 13 -25 218 41 32 '0 220 22 21*3 221 57 56-6 25'4 24 '9 24'5 51 29 36*9 50 25 12-1 49 19 53 -0 4'5 4'4 4 '3 9 '27384 9 -27533 9-27712 13-375 223 28 33 '2 24 -0 + 48 13 52 '9 4'2 9-27919 at its appearance in the Years 1835 < 1836. 235 TABLE X. continued. Date. Apparent Right Ascension. Pertur- bations. Apparent Declination. Pertur- bations. Log. of True Dist. from the Earth. 1835. Oct.13'375 13 '5 13 '625 f // 223 28 33 '2 224 54 26 '9 226 15 52 -2 // 24-0 23-6 23 -1 1 // + 48 13 52'9 47 7 24 -8 46 40 '4 /; 4-2 4 -1 4-0 9*27919 9 -28154 9-28415 13 75 13 '875 14'0 227 33 5 -1 228 46 19-8 229 55 50 '7 22 *7 22 '2 21 -8 44 53 50 '9 43 47 6 '3 42 40 35 '8 -3-9 3-8 3-7 9 -28702 9 -29014 9 '29349 14 '125 14 '25 14-375 231 1 50 '6 232 4 33 -0 233 4 9 '5 21 -4 21 -0 20-6 41 34 27-4 40 28 49 "2 39 23 48 -2 3 '5 3 -3 3-1 9 '29706 9 '30085 9 '30484 14-5 14 '625 1475 234 051-6 234 54 49 "6 235 46 13-5 20 '2 20 -0 19 '8 38 19 30 -2 37 16 o-i 36 13 23 -0 -2-9 2-6 2-2 9 '30902 9 -31337 9*31789 14 -875 15 -0 15-125 236 35 12 -6 237 21 56'0 238 6 31 -1 19 '6 19'4 19 '2 35 11 42'9 34 11 3-3 33 11 26-5 1 -8 1 -3 0-9 9 '32257 9 '32738 9 '33232 15 -25 15 -375 15 -5 238 49 6 -0 239 29 48 -0 240 8 43 -4 -19*0 18 -8 187 32 12 55-3 31 15 31 -5 30 19 16-5 0-4 + 0-1 0-6 9 '33738 9 '34255 9 '34782 15 '625 15 -75 15 -875 240 45 58 -1 241 21 38 -2 241 55 49 'I 18-5 18-3 18 -1 29 24 10 '7 28 30 15-4 27 37 31 -1 -f- i-o 1 '4 1'9 9 '35318 9-35861 9-36411 16-0 16-25 16-5 242 28 35 '2 243 30 12 '2 244 27 4 -3 -17-8 17-3 16-7 26 45 57 -8 25 6 22 -0 23 31 24-8 + 2-3 3-0 37 9 '36967 9 '38095 9 '39239 1675 17*0 17-25 245 19 39 -3 246 8 24 '0 246 53 40 -1 16-2 15 -6 15-1 22 59-3 20 34 57 -2 19 13 7 '9 + 4'2 4-6 4-9 9 -40392 9*41551 9 '42712 17-5 1775 18 -0 247 35 48 '7 248 15 6 -0 248 51 48 -0 14-5 14 -0 13 -4 17 55 21 -4 16 41 25 -1 15 31 8 7 + 5-2 5-3 5'4 9*43871 9 -45026 9 -46174 18-25 18 '5 18-75 249 26 7 -8 249 58 18 7 250 28 30 -2 12-9 12 -4 12 -0 14 24 20-1 13 20 48 '6 12 20 22 '9 + 5-4 5-3 5 'I 9-47313 9 '48442 9 '49559 19*0 19 "25 19-5 250 56 53 -1 251 23 34-9 251 48 44 '8 -11-6 11 -3 11 -0 11 22 52-5 10 28 7'3 9 35 57 -6 + 4-9 4-6 4-3 9 -50663 9-51753 9 '52828 1975 252 12 28 -5 -10-7 + 8 46 14'2 + 4'0 9 '53889 -236 the Elements of the Orbit of Halley's Comet, TABLE X. continued. Date. Apparent Right Ascension. Pertur- bations. Apparent Declination. Pertur- bations. Log. of True Dist. from the Earth. 1835. Oct. 19 '75 20 -0 20'25 o / // 252 12 28 '5 252 34 53 '3 252 56 4-1 n -107 10 -4 10-1 / // + 8 46 14-2 7 58 48 '5 7 13 32 -1 n + 4-0 37 3'5 9*53889 9 -54935 9 -55964 20 '5 20-75 21 -0 253 16 6-3 253 35 4 7 253 53 3 '9 - 9'9 97 9'5 6 30 17 -8 5 48 57-6 5 9 25 '6 + 3'2 3-0 27 9 "56979 9 '57977 9 -58960 21 '25 21 '5 21 75 254 10 6'9 254 26 18 -4 254 41 40 -6 -9'3 9-1 8-9 4 31 34'9 3 55 20 '3 3 20 35 '8 + 2'5 2 -3 2-1 9 '59928 9 -60879 9*61816 22-0 22 -25 22-5 254 56 17-2 255 10 10 -0 255 23 22-9 8-8 87 8-6 2 47 167 2 15 17 -8 1 44 34 '9 + '8 6 5 9 '62/37 9 -63643 9 '64534 2275 23 -0 23 -25 255 35 56-6 255 47 54 -4 255 59 17 -4 8-5 8-4 8-3 1 15 3'3 46 39 '5 -r- 19 19 '6 + '3 1 o 9-65411 9 -66274 9-67122 23-5 23*75 24-0 256 10 8 '6 256 20 28 -6 256 30 197 8-2 8-1 8'1 6 59-5 32 21 -2 56 48 '6 + 0-9 0-8 07 9 '67957 9 -68778 9-69587 24-25 24-5 24 75 256 39 42 -5 256 48 39 -4 256 57 10 -0 8-0 7'9 7-8 1 20 24 '5 1 43 11'4 2 512*3 + 0-6 0-5 '4 9'70382 971165 971935 25-0 25 -25 25'5 257 5 17-1 257 13 -5 257 20 22 '6 ~ 77 7-6 7-5 2 26 29 -0 2 47 3'9 3 6 59 -0 + 0-3 0-3 0-2 9 -72694 973441 974176 25 -75 26-0 26-25 257 27 23 -2 257 34 4 '2 257 40 25 -1 -7'4 7-4 7-3 3 26 15 '9 3 44 567 433'1 + 0-1 '1 o-o 9 -74900 9-75613 976315 26-5 2675 27-0 257 46 28 '2 257 52 12 7 257 57 40 *5 - 7-2 7-1 7-0 4 20 36 -6 4 37 39 -3 4 54 11-9 o-o O'O o-o 9 77007 9 77688 9 78360 27-25 27-5 2775 258 2 51 -1 258 7 46 -6 258 12 25 '9 - 7-0 6-9 6-8 5 10 16-0 5 25 52 '9 5 41 37 o o- o 979021 9 -79673 9 -80316 28-0 28-25 28 '5 258 16 51 -0 258 21 '9 258 24 58-4 - 67 6-6 6-6 5 55 49 '5 6 10 11 '7 6 24 ll'O o- o 0-2 9 '80949 9 -81 .-,73 9 -82189 29-5 258 38 35 7 -6-3 7 16 38 '9 0-2 9 -84567 at its appearance in the Years 1835 4' 1836. 237 TABLE X. continued. Date. Apparent Right Ascension. Pertur- bations. Apparent Declination. Pertur- bations. Log. of True Dist. from the Earth. 1835. Oct. 29 -5 30-5 31 '5 o / // 258 38 35 7 258 49 3 '3 258 56 42 '3 // -6-3 6-1 5'9 / II 7 16 38 '9 8 4 10-8 8 47 30 7 // 0-2 0*3 0'3 9 '84567 9-86818 9 '88953 Nov. 1 '5 2-5 3 '5 259 1 49'3 259 4 38'4 259 5 21 '5 - 57 5 '5 5 '4 9 27 15 -o 10 3 53'6 10 37 51 '2 0-4 0'4 0'5 9 -90979 9 -92905 9 '94737 4 '5 5 '5 6-5 259 48'8 259 1 9 '3 258 56 31 '2 5-4 5'4 5'4 11 9 28'9 11 39 4'4 12 6 52'4 0*5 0'6 07 9 4 96482 9*98144 9 '99729 7'5 8 '5 9 '5 258 50 21 -2 258 42 46 '2 258 33 52 '0 5 *5 57 5 '8 12 33 5 '8 12 57 55 '4 13 21 30 '5 -8 0-9 i -o '01240 -02681 '04056 10 '5 11 '5 12-5 258 23 44 "J 258 12 30 -0 258 12 *9 -6-0 6-0 5 '8 13 43 59'2 14 5 28 *2 14 26 4-1 1 -1 1 '2 1 'I 0-05367 o -06617 o -07309 13 '5 14-5 15'5 257 46 59 '2 257 32 53 *8 257 18 2'2 5'5 5'1 5 *1 14 45 51 '6 15 4 55 '4 15 23 19 '3 1 'I 1 -0 1 -0 '08945 o -10027 o -11057 16'5 17-5 18 '5 19*5 20 '5 21 '5 257 2 29*4 256 46 20 '4 256 29 39 '8 256 12 32'3 255 55 2 '8 255 37 15 '2 5*4 5 '8 6'3 - 67 6-8 6-8 15 41 7'0 15 58 21 '5 16 15 5 '2 16 31 207 16 47 9*9 17 2 34'9 1 'I I '2 1 -3 1 '4 1 -4 1 '4 -12037 o -12968 0*13853 o -14692 '15489 o -16243 22 '5 23'5 24 '5 255 19 13'5 255 1 1 '4 254 42 42 '5 -6-8 6-9 7-2 17 17 37'2 17 32 18'4 17 46 397 1 '5 1 '5 1-6 0-16957 o -17633 0'18271 25'5 26-5 27-5 254 24 19'8 254 5 56-4 253 47 34 '3 -7'6 7*9 8*2 18 42'5 18 14 27 7 18 27 56-6 - l'7 1 '8 1*9 -188/3 0-19441 -19975 28 '5 29 '5 30-5 253 29 16 '6 253 11 4'6 252 52 59 '9 8'4 8 '5 8'5 18 41 lO'O 18 54 9'1 19 6 54 '6 - 1'9 2 -0 2'0 -20478 0-20951 0-21394 Dec. 1 '5 2'5 3 '5 252 35 4'1 252 17 18 *5 251 59 43 7 8-5 8 '5 8*5 19 19 27*2 19 31 47-9 19 43 57 -2 2-0 2-0 2-1 0-21809 '22198 0-22561 4'5 251 42 20 '6 -8-6 -19 55 56-1 2-1 '22899 238 On the Elements of the Orbit of Hollers Comet, TABLE X. continued. Date. Apparent Right Ascension. Pertur- bations. Apparent Declination. Pertur- bations. Log. of True Dist. from the Earth. 1835. o ; // ii o / // // Dec. 4 '5 251 42 20 '6 -8-6 19 55 56*1 2'1 '22899 5'5 251 25 8 *5 8-6 20 7 45 '2 2 'I '23213 6'5 251 8 9 '5 87 20 19 24 '8 2'1 -23505 7-5 250 51 22'4 -8-9 20 30 55 '9 2-0 o -23775 8'5 250 34 47*1 9-2 20 42 19-1 2*0 '24023 9*5 250 18 23 7 9'5 20 53 34 7 2'0 -24252 10'5 250 2 11-8 -97 21 4 43 '4 2-1 -24461 11 '5 249 46 10 '5 97 21 15 45 '8 2 '3 -24652 12-5 249 30 19 -5 9'6 21 26 42 *2 2'4 '24824 13'5 249 14 37-6 - 9'6 21 37 33 -0 -2-6 -24979 14'5 248 59 5 -0 9'6 21 48 18 '9 27 0-25116 15'5 248 43 40 -2 9'6 21 59 O'l 2'8 -25238 l6'5 248 28 22 '4 -97 22 9 37-2 -2-9 -25344 17-5 248 13 9*9 9 '9 22 20 10 -6 2'9 -25434 18 '5 247 58 3 -0 10-2 22 30 40 '6 2'9 -25510 19-5 247 42 59 '5 -10*5 22 41 7 '5 3-0 o -25571 20 -5 247 27 58 '8 10'8 22 51 3i 7 3 -1 -25618 21 '5 247 12 59 "8 11 -0 23 1 53 '6 3 *2 '25651 22-5 246 58 0'8 11 -1 23 12 13'2 3'2 o -25672 23'5 246 43 -3 11'2 23 22 31 '5 3 '3 '25679 24'5 246 27 58 -1 11 '3 23 32 48 '1 3'4 o -25674 25*5 246 12 52'2 11 '4 23 43 3 '5 3'5 -25656 26*5 245 57 41 -8 11-6 23 53 17 '9 37 o -25627 27-5 245 42 24 "9 11 -8 24 331'8 37 -25586 28 '5 245 27 1 '4 12-0 24 13 45 '0 3'8 -25534 29*5 245 11 28-8 12 -2 24 23 58 'I 3-9 o -25470 30 '5 244 55 46 '8 12 '3 24 34 1 1 "2 3-9 o -25396 31 '5 244 39 53 '4 12-4 24 44 24 '5 4'0 0-25311 1836. Jan. 1 '5 244 23 47 '3 12-5 24 54 38 *2 4-1 -25215 2'5 244 7 27 -0 12-6 25 4 52 '4 4'2 0-25109 3'5 243 50 51 *3 12 '8 25 15 7'6 4'2 o -24994 4'5 243 33 59 '2 13 -0 25 25 23 *3 4'3 -24868 5'5 243 16 47 '6 13'2 25 35 40 -2 4 '4 o -24733 6-5 242 59 17-4 13-5 25 45 58 '2 4'5 -24589 7-5 242 41 24-9 13'8 25 56 17-5 4 '5 0-24435 8 '5 242 23 9 7 14*1 26 6 38 '2 4-6 o -24272 9'5 242 4 29 -1 14 *3 26 17 0*2 - 47 0-24100 at its appearance in the Years 1835 $ 1836, 239 TABLE X. continued. Date. Apparent Right Ascension. Pertur- bations. Apparent Declination. Pertur- bations. Log. of True Dist. from the Earth. 1836. Jan. 9 '5 10 '5 11 '5 o / // 242 4 29 -1 241 45 22 -6 241 25 48'0 // 14-3 14 '3 14*3 / // 26 17 -2 26 27 23 '6 26 37 48 '5 // -47 4 '8 4'8 0-24100 0'23919 o -23730 12*5 13'5 14-5 241 5 43 '8 240 45 7 '5 240 23 57 -2 14-4 14*4 14-5 26 48 14 '8 26 58 42 '6 27 9 117 ~4'9 5-0 5*1 -23532 -23326 0-23112 15 '5 l6'5 17-5 240 211 '8 239 39 48 '7 239 16 45 7 14-5 14-6 147 27 19 42'1 27 30 13-8 27 40 46 '5 5-2 5'3 5*4 -22890 o -22661 -22424 18 '5 19*5 20-5 238 53 1 'I 238 28 33 '1 238 3 19*4 14-8 15 -1 15 '4 27 51 20 -0 28 1 54 '1 28 12 28 '6 5-5 5-6 57 o -22179 o -21927 o -21669 21 -5 22'5 23-5 237 37 17'0 237 10 24 'I 236 42 39 7 -157 16'1 16 '5 28 23 3-1 28 33 37'3 28 44 10 *8 5'8 5*9 5'9 -21404 0-21132 -20854 24'5 25-5 26 '5 236 14 '3 235 44 23 '3 235 13 477 16'9 17'3 17-8 28 54 43 'I 29 5 13'5 29 15 42-1 -6-0 6-1 6-2 o -20570 -20281 -19986 27-5 28 -5 29*5 234 42 10-8 234 9 297 233 35 42 "6 18-1 18 '5 18 '9 29 26 7 -6 29 36 29 7 29 46 47 '2 -6-2 6-3 6-4 o -19687 -19382 0-19073 30-5 31 '5 Feb. 1 '5 233 46 '5 232 24 39 '9 231 47 19-2 -19'3 19 '5 197 29 56 59-9 so 7 6-4 30 17 5*6 -6-5 6-5 6*6 0'18760 0-18443 0-18124 2'5 3 '5 4'5 231 8 42 '8 230 28 48 '8 229 47 34 '2 -19'9 20 'I 20*6 30 26 56 '6 30 36 38 '2 30 46 8-9 -6-6 6-6 67 0-17801 0-17475 o -17148 5 *5 6'5 7'5 229 4 567 228 20 54 '5 227 35 23 '9 21 '4 22 '4 237 30 55 27-1 31 4 32 -0 31 13 21 -0 -6-8 6-9 6-9 o -16819 -16489 0-16158 8'5 9'5 10 '5 226 48 25 '4 225 59 54 '8 225 9 50 '6 24 '6 25'3 25 '8 31 21 52'8 31 30 5 '5 31 37 56'9 -6-9 7-0 7-0 '15828 -15498 0-15170 11 '5 12 '5 13 '5 224 18 12 '2 223 24 56 '9 222 30 4 '4 26'2 26-4 267 31 45 24'5 31 52 26-5 31 59 0'4 - 7-0 6-9 6-9 0*14844 0*14520 '14200 14'5 221 33 34 '5 -27 -2 32 53-3 -6-9 0-13884 240 On the Elements of tlie Orbit of Halky's Comet, TABLE X. continued. Date. Apparent Right Ascension. Pertur- bations. Apparent Declination. Pertur- bations. Log. of True Dist from the Earth. 1836. Feb. 14 '5 15 '5 16'5 / .'/ 221 33 34 '5 220 35 25 -0 219 35 37 'I 11 o*: '2 277 28 '5 o / // 32 5 3'3 32 10 32 '8 32 15 26-0 // -6-9 6-8 67 '13884 o -13573 -13268 17'5 18'5 19-5 218 34 11 '3 217 31 6-0 216 26 24-8 29*3 30 "2 31 '2 32 19 40-2 32 23 12 -1 32 25 59 '2 -6-6 6-5 6-3 0-12971 '12680 0-12399 20 *5 21 '5 22'5 215 20 8 '6 214 12 19'2 213 2 59 -1 32*2 33-2 34'2 32 27 58-4 32 29 6 7 32 29 21'0 -6'2 6-0 5 '8 o -12127 0-11866 o -11617 23-5 24 *5 25 -5 211 52 12-3 210 40 3 '2 .209 26 34 '3 35'2 36-4 37 '5 32 28 38 '5 32 26 57'0 32 24 13 -0 - 5'6 5 '2 4 *8 0-11380 0-11157 '10948 26'5 27-5 28 '5 208 11 52 '7 206 56 2 '9 205 39 9*3 38'6 39-6 40 '2 32 20 24 '5 32 15 29'2 32 9 24 '3 4 '4 4 -0 3-6 0-10755 0-10579 -10420 29-5 Mar. 1 '5 2 *5 204 21 21 '8 203 2 45 '6 201 43 28 '8 40-6 41 '0 41 '3 32 2 9'2 31 53 41 '6 31 44 07 3'3 2 '9 2-6 0-10279 0-10158 '10058 3'5 4 '5 5'5 200 23 37-5 199 3 22'5 197 42 51 -0 41 -5 41 '6 42-0 31 33 57 31 20 55 '9 31 7 31 '6 2 '2 1'9 1 '5 o -09978 o -09919 '09884 6'5 7'5 8*5 196 22 10 '7 195 1 32 '4 193 41 3'3 42-5 43-0 43-6 30 52 53 '8 30 37 27 30 19 59-4 1 'I -0-6 o-o 0-09871 -09881 0-09915 9'5 10 '5 11 '5 192 20 51 '3 191 i 6-0 189 41 57'2 44-2 44'8 45'4 30 1 45'6 29 42 24 '4 29 21 58 '3 + 0-6 1 '2 1 '8 o -09974 0-10058 '10165 12-5 13'5 14'5 188 23 30 '6 187 5 54'9 185 49 17-9 -45'7 46-0 46-1 29 o 29'6 28 38 2 -0 28 14 39'4 + 2'3 2'9 3'5 0*10298 -10455 '10637 15-5 l6'5 17-5 184 33 45 -0 183 19 24-5 182 6 21 '9 -45-9 45'4 44 '8 27 50 25'0 27 25 24 -0 26 59 40 '6 -r- 3-8 4-0 4'2 0-10843 0-11073 o -11327 18-5 19'5 20 '5 180 54 41 -4 179 44 28 '5 178 35 47 *1 44-4 44 '3 44-2 26 33 18'5 26 6 22 '9 25 38 58 '3 + 4'5 4'9 5'4 o -11603 0-11903 -12223 21 *5 177 28 41 '6 44 '3 25 11 9'4 + 6-0 -12565 at its appearance in the Years 1835 <$* 1836. 241 TABLE X. continued. Date. Apparent Right Ascension. Pertur- bations. Apparent Declination. Pertur- bations. Log. of True Dist. from the Earth. 1836. Mar.21 '5 22'5 23 *5 24 '5 25*5 26*5 27-3 28 '5 29 '5 30 '5 31 '5 177 28 41 '6 176 23 13-5 175 19 26-0 174 17 21 '8 173 17 I'l 172 18 24 '9 171 21 34-4 170 26 29 *4 169 33 9*3 168 41 33 -0 167 51 38 '9 n 44-3 44 '4 44 '2 44 -0 43 '6 43'3 -43 '0 427 42-4 -42 '2 -42*2 o / // 25 11 9'4 24 43 '7 24 14 36'6 23 46 1 '5 23 17 19'6 22 48 34 7 22 19 50 '8 21 51 11 '6 21 22 39 '8 20 54 18 '5 20 26 9 '9 ii 6-0 6-3 6-3 6-3 6-4 6-5 6-9 7'4 7'8 '12565 o -12927 -13309 0-13709 0-14127 0-14561 0-15011 0'15475 0-15953 0-16445 o -16949 242 On the Elements of the Orbit of Halley's Comet, TABLE XL Containing 730 Equations of Condition for correcting the assumed Elements Orbit of HALLEY'S Comet, on July 30, 1835. of the Date. Equations of Condition dependent upon Right Ascensions. 1835. // II n u II II Aug. i -5 + 5'1 P 55*8 Q + 301 -0 R + 42-6 S + i-o U - i-o V = E 2*5 + 5-1 P 56-1 Q + 302-4 R + 42'6 S + I'l u 0-9 V = E 3*5 + 5-0 P 56-5 Q + 303-8 R + 42*6 S + I'l u 0-9 V Tjl 4-5 + 4*9 P - 56*7 Q + 305*1 R + 42-7 S + 1-2 u - 0-8 V t= E 5-5 + 4'8 P 56-9 Q + 306*4 R + 42 '7 S + 1-1 u - 0-8 V ^ E 6-5 + 4-7 P - 57-2 Q + 307-9 R + 42-8 S + I'l u 0-8 V = E 7*5 + 4-7 P 57*3 Q + 309*5 R + 42-8 S + 1-4 u 0-6 V = E 8*5 + 4-5 P 57*9 Q + 311-0 R + 42-9 S + 1-2 u 0*6 V = E 9'5 + 4 '6 P 58 -0 Q + 312-7 R + 43-0 S + 1-4 u 0-6 V = E 10*5 + 4-4 P 58 '2 Q + 314-4 R + 43-0 S + 1*4 u 0*5 V = E 11*5 + 4-2 P 58'5 Q + 315-9 R + 43-0 S + 1-3 u - 0-6 V = E 12 '5 + 4-2 P 53-8 Q + 317 '8 R + 43*1 S + 1*5 u 0*5 V =5 E 13-5. + 4-0 P 59-2 Q + 319 *7 R + 43-1 S + 1*4 u 0*4 V = E 14*5 + 3-9 P 59*5 Q + 321-5 R + 43-2 S + 1*5 u 0-4 V = E 15 '5 + 3-7 P 59*8 Q + 323 '3 R + 43-4 S + 1-5 ti- 0-3 V = E 16*5 + 3*6 P 60-2 Q + 325-3 R + 43*4 S + 1-6 ll 0*2 V = E 17*5 + 3'3 P 60-6 Q + 327-3 R + 43-4 S + 1-7 u 0-3 V T? 18*5 + 3-2 P 60-9 Q + 329*6 R + 43-5 S + 1-6 u - o-i V = E 19*5 -f 3-0 P 61-4 Q + 331 '7 R + 43-6 S + 1-5 u * = E 20-5 + 2-8 P 6l'8 Q + 333 '8 R + 43-7 S + 1-6 u + o-i V = E 21*5 + 2-6 P 62 -3 Q + 336*1 R + 43*7 S + 1'6 u + o-i V = E 22-5 + 2*4 P 62-6 Q + 338 -5 R + 43-8 S + 1-7 u + 0-2 V = E 23-5 + 2'3 P 63-1 Q + 340 '9 R + 44*0 S + 1-5 u + 0-4 V = E 24*5 + 1 '9 P 63*4 Q + 343 -5 R + 44-0 S + 1'7 u + 0-4 V = E 25-5 -f 1-6 P 64*0 Q + 346 -1 R + 44-2 S + 1-9 u + 0-5 V = E 26-5 + 1 -5 P 64-5 Q + 348 -8 R + 44-3 S + 1-9 u + 0-5 V = E 27-5 + 1-4 P 64-9 Q + 351*8 R + 44-6 S + 2'0 u + 0-7 V =r E 28-5 + 0-8 P 65-5 Q + 354-5 R + 44-5 S + 2-1 u + 0*8 V = E 29-5 + 0-6 P 66*0 Q + 357-6 R + 44-6 S + 2-1 u + i-o V = E 30*5 + 0*2 P 66-7 Q + 360-7 R + 44-7 S + 2-1 u + i-o V = E 31-5 0-3 P 67-3 Q + 363*9 R + 44 '9 S + 2'2 u + 1-1 V = E at its appearance in the Years 1835 $ 1836. 243 TABLE XL continued. Containing 730 Equations of Condition for correcting the assumed Elements Orbit of HALLE Y'S Comet, on July 30, 1835. of the Date. Equations of Condition dependent upon Declinations. 1835. w II // /t /; II Aug. i 5 4'2 p + 16-2 Q - 88 '9 R 11-5 S + 14 '5 U - 4-3 V = E 7 2 5 4-3 p + 16-4 Q 90-3 R 11-5 S + 14-4 U 4-2 V = E 7 3 5 4-5 p + 16-8 Q 91 '8 R n-6 S + 14-5 Ti- 3-9 V = E 7 4 5 4-5 p + 17*0 Q 93-3 R 11-8 S + 14 '6 ll 3-7 V = E 7 5 5 4-6 p + 17-3 Q 94-6 R 11-8 S + 14-8 IT - 3-5 V = E 7 6 5 4-8 p + 17'5 Q 96 -4 R - 12 '1 S + 14-7 U - 3-3 V = E 7 7 *5 5-0 p + 17 '9 Q 98-1 R 12-1 S + 14*8 U 3-1 V = E' 8 5 5'0 p + 18-3 Q 99-6 R 12-6 S + 15'0 U - 2-9 V rr E 7 9 5 4 '9 p + 18-5 Q 101 -4 R 12-5 S + 15 -1 U - 2-6 V == E 7 10 5 5*4 p + 18-8 Q 103*2 R 12-8 S + 15-0 u 2-4 V == E 7 11 5 5-4 p + 19 '2 Q 104-9 R- 12-8 S + 15-2 Ti- 2-2 V = E 7 12 5 5-6 p + 19-4 Q 107*0 R 13-0 S + 15-2 ll - 2~-0 V = E 7 13-5 5-5 p + 19'9 Q 103 '9 R- 13-1 S + 15J4 U - 1-6 V = E 7 14 5 5-6 p + 20-2 Q 110-9 R 13*4 S + 15*5 U 1-3 V = E 7 15 5 5-7 p + 20-6 Q 113-0 R 13-7 S + 15-6 U - 1-1 V = E 7 16 5 6-0 p + 21-1 Q 115-2 R 13-9 S + 15-6 U - 0-9 V = E 7 17 5 6-0 p + 21 -4 Q 117-6 R- 13 '8 S + 15-8 U 0-6 V = E 7 18 5 6-2 p + 21-8 Q 120*2 R 14-1 S + 16-0 U 0-3 V == E 7 19 5 6-3 p + 22-4 Q 122 -2 R - 14 : 4 S + 16-0 U * = E 7 20 5 6-8 p + 22-7 Q 124 *9 R- 14-8 S + 16-1 u + 0-3 V = E 7 21 5 6-8 p + 23-2 Q 127-7 R 15-0 S + 16-2 u + 0-6 V == E' 22 *5 6-9 p + 23-8 Q 130 -2 R- 14-9 S + 16-5 u + 0-9 V = E 7 23 5 7-5 p + 24-1 Q 133-5 R 15-7 S + 16-3 u + i-o V = E 7 24 5 - 7'3 p + 24-8 Q 136-2 R 15-7 S + 16-7 u + 1-6 V = E/ 25 5 7*7 p + 25'3 Q 139*5 R 16-1 S + 16-9 u + 2-0 V = E 7 26 5 Q O O 1 p + 25-9 Q 142'7 R 16-7 S + 17-0 u + 2-3 V = E 7 27 5 8-4 p + 26-3 Q 146-5 R- 16-8 S + 17-0 u + 2-7 V = E 7 28 5 8-6 p + 27*2 Q 149-9 R - 17-2 S + 17-4 u + 3-1 V = E 7 29 5 8-9 p + 27-8 Q 153-6 R - 17-0 S + 17-5 u + 3'6 V = E-' 30 5 9'0 p + f\ 157-8 R 17-5 S + 17-6 u + 4-0 V = E 7 31 5 p + 29 *4 162-1 R 18-0 S + 17-9 u + 4-5 V = E 7 244 On the Elements of the Orlit of Halky's Comet, TABLE XL continued. Date. Equations of Condition dependent upon Right Ascensions. 1835. Aug. 31 B 5 Sep. i-5 2-5 // // // // // // -3 P 67 '3 Q 4- 363 '9 R + 44 '9 S + 2 '2 U 4- 1 '1 V = E '5 P 67 '8 Q + 367 '2 R 4- 45 -1 S 4- 2 *4 U + 1 '3 V =r E o -9 P 6s -6 Q 4- 370 -7 R 4- 45 -2 S 4- 2 -3 U 4- i '4 V = E 3*5 4'5 5-5 1 -3 P -- 69 -1 Q 4- 374 -5 R 4- 45 -4 S 4- 2 -4 U 4- 1 '5 V =r E 1 -8 P 69 '8 Q + 378 -2 R + 45 '5 S 4- 2 -5 U 4- 1 '6 V = E 2 '2 P 70 '5 Q 4- 382 -1 R 4- 45 '7 S 4- 2 -6 U 4- 1 '8 V = E 6'5 7-5 8'5 2 '9 P 71 -3 Q 4- 386 '2 R + 45 -8 S 4- 2 -6 U 4- 2 '1 V = E 3 -4 P 72 -1 Q + 390 -5 R + 45 '9 S 4- 2 *7 U 4- 2 '2 V = E 4 -i P 73 -o Q 4- 394 -7 R + 46 -o S 4- 2 -7 U + 2 -3 V = E 9'5 10-5 11 '5 4'8 P 73-8 Q 4- 399'3 R 4- 46-3 S 4- 3-0 U 4- 2 "6 V = E 5 '5 P 74 '7 Q + 404 -1 R 4- 46 '4 S + 3 '0 U + 2 '8 V = E 6 '4 P 75 '6 Q 4- 409 -3 R 4- 46 -8 S + 3 -1 U + 2 -9 V ==: E 12 '5 13-5 14*5 7'3 P - 76-5 Q 4- 414-3 R 4- 46-8 S 4- 3-2 U 4- 3 '2 V = E 8'2 P 77-3 Q + 419-8 R 4- 47'2 S 4- 3'4 U + 3 '5 V = E 9 '4 P 78 -5 Q 4- 425 -4 R + 47 '3 S 4- 3 '4 U 4- 3 "] V = E 15*5 16-5 17-5 10 '5 P 79 '7 Q + 431 -0 R + 47 '5 S + 3 '5 U + 4 -0 V = E 11 -9 P so -8 Q + 437 -o R + 47 '7 S + 3 -7 U -f 4 -4 V = E 13 '3 P 81 '7 Q + 443 '8 R + 48 -0 S + 3 "9 U + 4 "] V =r E 18*5 19*5 20 -5 15'0 P 83-1 Q + 450'4 R + 48-1 S + 3*9 U + 5 '1 V = E 16 '8 P 84 '5 Q + 457 -0 R + 48 '2 S + 4 -3 U + 5 '4 V = E 18 '8 P 85 7 Q + 463 -9 R + 48 -5 S + 4 '4 U + 5 '9 V = E 21 '5 22 '5 23 '5 21 'I P 87 '2 Q + 471 '3 R + 48 '6 S + 4 '6 U + 6 '4 V = E 23 '6 P 89 'I Q + 478 '6 R + 48 '8 S + 4 '9 U + 7 -0 V r= E 26 -6 P 90 -o Q + 485 -9 R + 48 -8 S + 5 'i U + 7 -6 V = E 24 '5 25 '5 26 '5 29 9 P 90 -9 Q 4- 493 -6 R 4- 48 -9 S + 5 -4 U + 8 -2 V = E 33 '9 P 92 '5 Q 4- 500 '3 R 4- 48 -8 S + 5 '9 U + 8 '8 V = E 38 '3 P 94 '3 Q 4- 506 '6 R 4- 48 '6 S 4- 6 -1 U 4- 9 '8 V = E 27*5 28'5 29*5 43-6 P 94-7 Q 4- 512-6 R 4- 48-1 S 4- 6-6 U + 10-7 V = E 49 '8 P 96 -0 Q 4- 516 -4 R 4- 48 -0 S 4- 7 -1 U 4- 11 -8 V =r E 57 -4 P 96 -6 Q + 518 -o R 4 46 -7 S + 7 -7 U + 12 -9 V = E 30'5 Oct. 1 '5 1-75 66'3 P 96-5 Q 4- 516-3 R 4- 45-1 S 4- 8'5 U 4- 14-2 V =3 E 77-6 P 95-3 Q + 506-8 R 4- 42-8 S 4- 9'2 U 4- 15-9 V = E 80-6 P 94-7 Q + 504-1 R + 42-3 S 4- 9 '7 U 4- 16-4 V = E 2-0 2 '25 2-5 84 -o P 94 -i Q 4- 499 '6 R + 41 -4 S + 9 '7 U 4- 16 -9 V = E 87-5 P 93-3 Q 4- 495-0 R 4- 40-6 S +10-0 U 4- i7'4 V = E 91 -5 P 92 -3 Q 4- 489 -s R 4- 39 -6 S + 10 -i U 4- is -o V = E 2'75 95 '2 P 91 -0 Q 4- 483 -2 R 4 38 -8 S -J- 10 '5 U 4- 18 '6 V = E at its appearance In the Years 1835 8; 1836. 245 TABLE XL- -continued. Date. Equations of Condition dependent upon Declinations. 1835. II II a // // II Aug. 31 '5 9 "0 P + 29-4 Q- 162-1 R 18 -0 S + 17-9 u + 4-5 V = E' Sep. 1-5 10 -o P + 30-2 Q- 166-2 R 18 '2 S + 18 -0 u + 4-9 V = E' 2-5 10 1 P + 31 '2 Q- 171 -2 R 18-8 S + 18-3 u + 5-4 V = E 7 3 '5 10 5 P + 32-0 Q- 176-1 R 19 '3 S + 18-6 u + 6-0 V = E' 4-5 11 2 P + 32 '8 Q- 181-6 R 19-8 S + 18-7 u + 6-4 V = E' 5'5 11 4P + 34-0 Q- 187-0 R 20-2 S + 19-1 u + 7-1 V = E 7 6-5 11 8 P + 35'2 Q- 193 -o R 20-8 S + 19*3 u + 7'7 V = E' 7'5 12 4 P + 36'1 Q- 199*4 R 21 '2 S + 19-7 u + 8-4 V r= E' 8 '5 12 -9 P + 37-3 Q- 206 -2 R 22-1 S + 19'8 u + 8-9 V = E' 9 '5 13 5 P + 38 '8 Q- 213-6 R 22*5 S + 20'1 u + 9 '7V = E' 10 '5 14 2 P + 40*1 Q- 221 -3 R 23-3 S + 20 '4 u + 10-2 V = E' 11 '5 14 9P + 41 '4 Q- 229-9 R 23-8 S + 20-8 u + 11-1 V = E' 12 '5 15 6P + 43'2 Q- 238 '9 R 24-8 S + 21 -1 u + 12-0 V = E' 13-5 16 sP + 45 -1 Q- 248'7 R 25-7 S + 21-6 u + 12*8 V = E' 14 '5 17 3 P + 46-8 Q- 259-4 R 26-5 S + 22*0 u + 13-8 V =r E ; 15'5 1 O 1 O 3 P + 49-0 Q- 271 -i R 27'5 S + 22-3 u + 14-7 V = E' 16 -5 19 4 P + 51 '4 Q- 283-6 R 28 -6 S + 22'8 u + 15-8 V = E' 17'5 20 6P + 53'9 Q- 297-5 R 29 '6 S + 23-2 u + 16-8 V s= E' 18 -5 21 9 P + 56-7 Q- 313-2 R 31 -2 S + 23*8 u + 18-1 V = E' 19-5 23 '4 P + 59-6 Q - 329 *5 R 32 -4 S + 24 '4 u + 19'4 V = E' 20 '5 25 oP + 63-1 Q- 348 -3 R 34-1 S + 25-1 u + 20-8 V = E' 21 '5 26 9 P + 66-8 Q- 369-3 R 36-0 S + 25'6 u + 22-2 V = E' 22 '5 29 oP + 71-4 Q- 392-4 R 38 -1 S + 26 '4 u + 23 f 9 V = E' 23 '5 31 5 P + 75-7 Q- 419-0 R 40-4 S + 27'0 u + 25 '9 V = E' 24*5 34 oP + 81 '5 Q- 448-7 R 42-8 S + 28 *0 u + 27-6 V = E' 25 '5 37 2 P + 87'5 Q- 483-0 R 45 -8 S + 29-0 u + 29-6 V = E' 26-5 40 9 P + 94-1 Q- 522-6 R 49 *2 S + 29-8 u + 31 -8 V = E' 27-5 45 o P + 103 '2 Q- 566 -9 R 53-1 S + 30-9 u + 34-2 V =r E' 28-5 49 . 9 p + 112-3 Q- 621 -o R - 57-6 S + 32 -1 u + 36 '8 V r= E' 29-5 55 6 P + 123-4 Q- 683 -8 R 63*0 S + 33-3 u + 39-8 V = E' 30*5 62 3 P + 137-2 Q- 757-2 R 69*4 S + 34-7 u + 42 '9 V = E' Oct. 15 70 2 P + 153'1 Q- 847 '4 R 76-9 S + 36-0 u + 46-3 V =r E' 1-75 ~ 72 sP + 157-6 Q- 372-2 R 79'1 S + 36-6 u + 47-2 V T?' J j 2-0 ;4 7P + 162-3 Q- 898 '2 R 81 -4 S + 37*0 u + 48-1 V = E' 2 -25 77 1 P + 167-4 Q- 925-6 R 83-7 S + 37'4 u + 49-1 V = E' 2'5 79 5 P + 172-5 Q- 954-5 R 86-1 S + 37'5 u + 50'0 V = E' 2 '/5 82 o P + 178-3 Q- 984 '8 R 88 -4 S + 38-0 u + 51'0 V = E' 246 On the Elements of the Orlit of Halleys Comet, TABLE XL continued. Date. Equations of Condition dependent upon Right Ascensions. 1835. Oct. 2-75 3-0 3'25 if 11 n it n 95'2 P 91 -0 Q + 483-2 R + 38-3 S +10-5 U 99-5 P 89-6 Q + 475-7 R + 37-6 S +10-7 U 104-0 P 37-8 Q + 467-1 R + 37-0 S +11-1 U + 18-6 V = E + 19-1 V = E + 19-7 V == E 3 '5 3-75 4-0 108-8 P 86-0 Q + 456-9 R + 35-0 S +11'4 U 113-8 P 84-0 Q + 4i5'4 R + 33 '6 S + 11 '9 U 119-3 P 81-8 Q + 431'S R + 31 '8 S +12 -2 U + 20 -2 V r= E + 21-0 V = E + 21 -6 V *= E 4-25 4-5 4-75 125-1 P 79-5 Q + 416-4 R + 29-8 S +12-7 U 131-4 P 76-3 Q + 398-7 R + 27-3 S +13-1 U 138-0 P 72-7 Q + 378-8 R + 25-1 S +13 '7 U + 22 -2 V = E + 22-9 V = E + 23-7 V == E [ vsr 5 * 5-25 5-5 145-2 P 68 '7 Q + 355 '9 R + 22 '3 S + 14 '0 U 152-7 P 63-9 Q + 330-4 R + 19'6 S +14-7 U 161 -4 P 58 -4 Q + 300 '9 R + 15 -9 S + 15 -1 U + 24 *6 V = E + 25 '5 V = E + 26 *4 V = E 5-75 6-0 6*125 170-3 P 52-3 Q + 268-0 R + 12-3 S +15'7 U 180 ; P 45*3 Q + 230-0 R + 7 '8 S + l6 '3 U 185-0 P 41-4 Q + 208-8 R + 5'5 S +l6'6 U + 27-4 V =r E + 28 -4 V = E + 28-9 V = E 6-25 6-375 6-5 190-2 P 37-3 Q + 186-2 R + 3-1 S +17-0 U 195 -7 P 33 -o Q + 161 -9 R + o -5 S .+ 17 -2 U 201-4 P 28-3 Q + 135-9 R 2 '2 S +17 '5 U + 29 -4 V = E + 29 -9 V = E + 30-4 V = E 6 '625 6-75 6-875 207-2 P 23-3 Q + 108-0 R 5-1 S +18-0 U 213-3 P 17-8 Q + 78-1 R 8-2 S +18-5 U 219-8 P 11-9 Q + 46-0 R 11-5 S +18-8 U + 31 -o V = E + 31-6 V = E + 32 -1 V = E 7-0 7-125 7-25 226-5 P 5-7 Q + 11-7 R is-o S +19*1 U 233-2 P + 0-8 Q 24-8 R 18-6 S +19 '6 U 240-3 P + 7'8 Q 63-8 R 22-4 S +20-0 U + 32-7 V = E + 33 -4 V =: E + 34-1 V == E 7-375 7-5 7-625 247-8 P + 15-2 Q 105-7 R 26-6 S +20-4 U 255 -6 P + 23 -3 Q 150 '4 R 31 *0 S +20 '8 U 263 -5 P + 32 -2 Q 198 -0 R 35 -6 S +21 *3 U + 34-7 V = E + 35 -3 V = E + 36-0 V = E 7*875 8 -0 271 -6 P + 41 -8 Q 249 -o R 40 -5 S +21 9 U 280 -3 P + 51 '9 Q 303 "} R 45 '6 S +22 '3 U 289*4 P + 62-7 Q 362-1 R 51-1 S +22-7 U + 36 -6 V = E + 37 -2 V == E + 37-8 V = E 8-125 8 '25 8-375 298 '7 P + 74 -3 Q 424 -4 R 57 '0 S +23 '4 U 308-1 P + 86-7 Q 490-9 R 63-3 S +24-0 U 318-1 P + 99*9 Q 561-6 R 70*1 S +24-4 U + 38 '4 V = E + 39 -0 V =r E + 39-7 V = E 8-5 8-625 8-75 328 -6 P +114-0 Q 636-9 R 77-2 S +24-8 U 339-0 P +129*0 Q 716-9 R 84-6 S +25-5 U 349 -5 P + 144 '9 Q 801 -8 R 92 '4 S + 26 '1 U + 40 -3 V = E + 40 -9 V = E + 41-5 V = E 8 -875 360-3 P +161-8 Q 892-6 R 100-6 S +26-6 U + 42 -1 V = E at its appearance in the Years 1835 fy 1836. 247 TABLE XL continued. Date. Equations of Condition dependent upon Decimations 1835. Oct. 2 -75 82 'oP + 178-3 Q II 984 -8 R // 88 -4 S // + 38 -0 u + Bl'-O V E' 3-0 84 7 P + 184-2 Q 1016 '9 R 91 -0 S + 38-5 u + 51-8 V E' 3*25 87 5 P + 190-6 Q 1050-5 R 93-7 S + 38 -8 u + 52-8 V : ' V 3 *5 90 4 P + 197-1 Q 1086-1 R 96-7 S + 39-1 u + 53-6 V E' 3 -75 93 3 P + 203-9 Q 1123 -4 R 99'8 S + 39-5 u + 54-6 V E' 4'0 - 96 5P + 211 '0 Q 1162-9 R 103-2 S + 39-9 u + 55-6 V ; E' 4*25 99 7P + 218 -0 Q 1204 *5 R 106-7 S + 40 -4 u + 56-6 V = E' 4'5 102 8 P + 226-2 Q 1248-2 R 110-6 S + 40-8 u + 577 V E 1 4-75 106 1 P + 234-6 Q 1294-0 R 114 -4 S + 41-1 u + 58-6 V r E' 5*0 109 6 P + 243 '2 Q 1341-9 R 118 *4 S + 41-5 u + 59-4 V E' 5'25 112 8 P + 252-7 Q 1392 -o R 122-4 S + 41-9 u + 6o-4 V : ' E' 5'5 116 sP + 262-5 Q 1444-8 R 126-8 S + 42 -0 u + 61-0 V *"-* E' 5'75 119 7 P + 272-7 Q 1499 '5 R 131 -3 S + 42*4 u + 61-8 V = E' 6-0 123 1 P + 283 -0 Q 1557*3 R 135-6 S + 42-5 u + 62-3 V r ; E' 6-125 124 6 P + 288-5 Q 1587 '2 R -137 -9 S + 42-7 u + 62-5 V r~* E 7 6-25 126 l P + 294-0 Q 1617-7 R 140-4 S + 42-8 u + 62-7 V T~* E 7 6-375 127 4P + 299-7 Q 1648 '9 R 142*9 S + 42-9 u + 63-0 V r E' 6-5 128 7P + 305-5 Q 1680 -6 R 145-6 S + 42-9 u + 63-2 V r~r" E 7 6 -625 130 -0 P + 311-4 Q 1712*9 R 148-2 S + 42-9 u + 63-4 V = E' 6-75 131 2 P + 317-4 Q 1745-6 R 150-8 S + 42-9 u + 63-6 V r E 7 6-875 132 2 P + 323-5 Q 1778-6 R 153-3 S + 43-0 u + 63-7 V =r E' 7-o 133 1 P + 329-6 Q 1812 -0 R 155 '9 S + 43*0 u + 63-8 V = E 7 7'125 133 8 P + 335-6 Q 1845-6 R 158-5 S + 43-0 u + 63-9 V r-r E 7 7-25 134 3P + 341-7 Q 1879-5 R 161-1 S + 42-9 u + 63-9 V i**"" E 7 7-375 134 5 P + 348'1 Q 1913-6 R 163-5 S + 42*8 u + 63-8 V = E 7 7-5 134 6 P + 354-4 Q 19477 R 165-9 S + 42-6 u + 63-6 V r E 7 7-625 134 2 P + 360-6 Q 1981-5 R 168-3 S + 42 '4 u + 63-5 V _ E 7 7-75 133 5 P + 366-8 Q 2015-0 R 170-7 S + 42*2 u + 63-3 V = E 7 7-875 132 4 P + 372-8 Q 2048 -0 R 173-1 S + 42-0 u + 62-9 V r~* E 7 8-0 ^-130 9 P + 373-6 Q 2080-2 R 175-4 S + 41-7 u + 62-4 V == E 7 8*125 128 9P + 384-2 Q 2111 '5 R 177-5 s + 41'3 u + 62-1 V = E 7 8-25 126 5 P + 389-6 Q 2141 -4 R 179-4 S + 40-8 u + 61-8 V ; E 7 8-375 123 5 P + 394-6 Q 2169 -4 R 181 -0 S + 40-4 u + 60-9 V E 7 8 '5 119 8 P + 399-2 Q 2195 -a R 182*3 S + 39'9 u + 59-9 V ~ E 7 8 '625 115 sP + 403*3 Q 2218-7 R 183-6 S + 39'3 u + 59-0 V ,T E' 8-75 110 o P +406-9 Q 2239 -0 R 184-5 S + 38*7 u + 58-1 V :r E' 8-875 103 7 P + 409-9 Q 2255-7 R 184*8 S + 38-1 u + 57-1 V r E 7 248 On the Elements of the Orbit of Halley s Comet, TABLE XI . continued. Date. Equations of Condition dependent upon Right Ascensions. 1835. // II II a II II Oct. 8-875 36o -3 P + 161-8 Q 892-6 R 100 -6 S + 26-6 u + 42-1 V - "P 9-0 371 -3 P + 179-7 Q 937-6 R 109-3 S + 27-1 u + 42-6 V = E 9 '125 382-3 P + 198-5 Q 1088 -6 R 118 -4 s + 27*7 u + 43-1 V = E 9*25 393 -3 P + 218 '3 Q 1195-0 R 127*9 s + 28*3 u + 43-5 V = E 9-375 404 '3 P + 239-3 Q 1306 '7 R 137-6 s + 28-9 u + 43 '9 V s= E 9'5 415 '0 P + 261 -o Q 1423*4 R 147-7 s + 29-5 u + 44-2 V = E 9 '625 425-4 P + 283-6 Q 1545-2 R 158*1 s + 30-0 u + 44-3 V = E 9-75 435 -4 P + 306-8 Q 1671-3 R 168-8 s + 30-5 u + 44-3 V = E 9-875 445 -0 P + 330 -8 Q 1801*3 R 179-7 s + 30-8 u + 44-1 V = E 10-0 453 '8 P + 355*2 Q 1934*2 R 190-8 s + 31 -1 u + 43-8 V = E 10 '126 461 '7 P + 380-1 Q 2069 -3 R 202-0 s + 31-3 u + 43-4 V =r E 10-25 468 -6 P + 404-9 Q 2205*3 R 213*1 s + 31 -5 u + 42 '8 V 1'. 30 '375 474-5 P + 429*7 Q 2341 -2 R 224-1 s + 31-4 u + 42*0 V T? 10*5 479-0 P + 454-1 Q 2475*4 R 234 *7 s + 31-3 u + 41 -0 V = E 10-625 481-1 P + 473*0 Q 2606*2 R 244 -6 s + 31 -0 u + 39-8 V = E 10-75 481 -4 P + 501-0 Q 2732 -4 R 253 -8 s + 30*6 u + 38 -4 V = E 10-876 480 -5 P + 522*6 Q 2852*3 R 262 *4 s + 80*1 u + 36-9 V = E 11 4 477*9 P + 542-7 Q 2964-9 R 270 -2 s + 29'6 u + 35-2 V = E 11 '125 473 -5 P + 561-2 Q 3068 *8 R 277-2 s + 29-0 u + 33*4 V = E 11-25 467*4 P + 577-8 Q 3163-4 R 283*4 s + 28 -3 u + 31-4 V = E 11 *375 459-7 P + 592*3 Q 3247-4 R 288 *6 s + 27*6 u + 29-4 V = E 11 -5 450 *4 P + 604-7Q 3320 -5 R 292 -6 s + 26-8 u + 27-3 V = E 11-625 439*7 P + 615-0 Q 3382 -0 R 295 -1 s + 25*8 u + 25 -0 V = E 11 '75 427*9 P + 623*2 Q 3432-1 R 296-6 fc + 24-4 u + 22 *7 V = E 11 '875 415-3 P + 629-2 Q 3470 -6 R 297-6 s + 23-3 u + 20 -3 V = E 12-0 402 -0 P + 633-2 Q 3498-3 R 297-9 s + 22-3 u + 18-0 V s= E 12 -125 387 *7 P + 635 *3 Q 3515*4 R -296-9 s + 21 '3 u + 15*7 V -p 12-25 373-1 P + 635-7 Q 3523*0 R 295*2 s + 20*2 u + 13-5 V = E 12*375 358 -3 P + 634-5 Q 3521 '7 R 292-8 s + 19-1 u + 11*3 V = E 12-5 343 *2 P + 631 -7Q 3512-3 R 289*8 s + 18'0 u + 9-1 V = E 12 -625 327-8 P + 627-4Q 3495*6 R 286 -4 s + 16-8 u + 7*1 V = E 12-75 312*3 P + 621-8 Q 3472*2 R 282-5 s + 15-7 u + 5*2 V = E 12-875 297 *4 P + 615*4 Q 3442-8 R 278 *2 s + 14-7 u + 3-4 V -_ r* 13*0 282-7 P + 608-2 Q 3408 -1 R 273-6 s + 13-8 u + 1-6 V V i * 13*125 268 -2 P + 600-5 Q 3369 -1 R 268 *7 s + 13-1 u o-i V = E 13-25 254-0 P + 592-2 Q 3326 -3 R 263*5 s + 12*3 u 1*7 V = E 13-375 240 -4 P + 583-3 Q 3280-3 R 238 -0 s + 11-3 u - 3 -2 V = E at its appearance in the Years 1835 fy 1836. 249 TABLE XL continued. Date. Equations of Condition dependent upon Declinations. 1835. Oct. 8 '8 75 9-0 9*125 // // // // // // 103-7 P +409-9 Q 2255-7 R 184*8 S +38 "1 U + 57 '1 V = E 7 96-4 P +412-1 Q 2268*1 R 184-6 S +37*4 U + 56*1 V = E 7 88 *0 P +413 -3 Q 2275 -3 R 184 *1 S +36 '7 U + 54 '8 V = E 7 9*25 9-375 9'5 78*4 P +413*4 Q 2277-3 R 183'0 S +35*9 U + 53 *5 V = E 7 67-6 P +412*4 Q 2272-8 R -181-1 S +35-0 U + 52*1 V = E 7 55*4 P +410-1 Q 2261*1 R 178*4 S +34-0 U + 50 '7 V = E' 9*625 9*75 9*875 41*8 P +406*2 Q 2241*3 R 175*0 S +33*1 U + 49 *1 V = E' 26*7 P +400*6 Q 2212*5 R 170*8 S +32*1 U + 47 *4 V = E 7 10*3 P +393*3 Q 2173-9 R 165*8 S +30-7 U + 45-8 V = E' 10*0 10*125 10 '25 + 7*7 P +384-1 Q 2124*9 R 159*8 S +29*2 U + 44 *1 V = E' + 27*2 P +372*7 Q 2064*9 R 152*8 S +28*0 U + 42 *4 V = E' + 47*8 P +359-3 Q 1993-6 R 144*9 S +26*8 U + 40*7 V = E 7 10-375 10*5 10 '625 + 69*6 P +343*7 Q 1910*7 R 136-1 S +25*3 U + 39*o V = E' + 92*5 P +326-0 Q 1816-3 R 126*2 S +23*8 U + 37 *4 V = E 7 + 116*7 P + 306-1 Q 1710*2 R 115*1 S +22-6 U + 36*1 V = E 7 10-75 10-875 11-0 + 141-5 P +284-3 Q 1593*5 R 103 '2 S +21*4 U + 34 *9 V = E 7 + 166*6 P +260*6 Q 1466-9 R 90*7 S +20-2 U + 33*9 V = E 7 + 191*8 P +235-4 Q 1331*7 R 77-5 S +19'0 U + 33*1 V r= E' Il f 125 11-25 11 '375 + 217*1 P +208-9 Q 1189-0 R 63*7 S + 18-2 U + 32*7 V = E 7 + 242*0 P +181*4 Q 1040-8 R 49 *6 S +17*4 U + 32 '5 V = E 7 + 265-9 P +153-1 Q 888-8 R 35*6 S +l6'5 U + 32 *5 V = E 7 11*5 11-625 11-75 + 288*9 P +124*6 Q 734-8 R 21-5 S +15*6 U + 32 *7 V = E 7 + 310*9 P + 96*2 Q 580-3 R 7*5 S +15-3 U + 33-5 V = E 7 + 331*6 P + 68*1 Q 427-0 R + 6*4 S +15-0 U + 34*5 V = E 7 11*875 12*0 12*125 + 350*6 P + 40-8 Q 277*0 R + 20*0 S +14*9 U + 35*7 V = E 7 + 368-0 P + 14*4 Q 131*3 R + 32*4 S +14-8 U + 37 *2 V = E 7 + 383-6 P ll'O Q + 8*4 R + 44*3 S +14 '8 U + 38 *8 V = E 7 12-25 12*378 12*5 + 397-7 P 35*0 Q + 141*5 R + 55*6 S +15 '0 U + 40-8 V = E 7 + 409-5 P 57*2 Q + 267'0 R + 66-2 S +15*4 U + 43*2 V = E 7 + 419*7 P ~ 77-6 Q + 384*5 R + 76*2 S +16-0 U + 45*8 V = E 7 12 *625 12-75 12*875 + 429 *0 P 96 -0 Q + 493 *5 R + 85 -3 S + 16 *7 U + 48 *2 V = E 7 + 436-8 P 112*7 Q + 593*7 R + 93*4 S +17*4 U + 51-0 V = E 7 + 442*4 P 127*8 Q + 684-8 R + 100 *7 S + 18 *1 U + 53 '8 V = E 7 13*0 13*125 13-25 + 446-4 P 141-2 Q + 767-2 R +106*9 S +18-8 U + 56 -6 V = E 7 + 449-1 P 153-1 Q + 840*8 R +112*4 S +19*6 U + 59 *6 V = E 7 + 450*5 P 163-5 Q + 906-0 R +117*2 S +20-5 U + 62*5 V = E 7 13-375 + 450'7 P 172*3 Q + 962-9 R +121*4 S +21*4 U + 65-3 "V = E' NAUTICAL ALMANAC, 1839, APPENDIX. 250 On the Elements of the Orbit of Halley's Comet, II TABLE XL continued. Date. Equations of Condition dependent upon Right Ascensions. 1835. Oct. 13 -37 13-5 13-62 " // // // // // 240-4 P +583-3 Q 3280 '3 R 258 '0 S +11-3 U 3 '2 V = E 227-2 P 4-574-2 Q 3231-5 R 252 '4 S +10 '3 U 4 -6 V = E 214-2 P +565-2 Q 3180-3 R 246 '8 S + 9 '6 U 5 -ft V = E 13*75 13-87 14'0 201 -6 P +556 -1 Q 3127 -2 R 241 -1 S + 8 -9 U 7 ! V = E 189-6 P +546-7 Q 3072-4 R 235-4 S + 8'2U 8 '1 V = E 178-0 P +537-0 Q 3016-5 R 229-7 S + 7-6 U 9 -o. V = E 14-12 14-25 14-37 166-8 P +527-1 Q 2959-8 R 224-0 S + 7-0 U 10-0 V = E 156 -2 P +517 -2 Q 2902 -7 R 218 '3 S + 6 '5 U 11 '0 V = E 146 -2 P +507 -3 Q 2845 5 R 212 '6 S + 5 -8 U 11 '7 V = E 14*5 14-625 14-75 136-6 P +497*3 Q 2788-2 R 207-0 S + 5-2 U 12-3 V = E 127-3 P +487-2 Q 2730-8 R 201-4 S + 4-7 U 13-0 V = E 118-3 P +477-0 Q 2673-6 R 195-9 S + 4-3 U 13-6 V = E 14-875 15-0 15125 109-8 P +466-6 Q 2616-8 R 190-6 S + 3-9 U 14 -i V = E 101-7 P +456-3 Q 2560-6 R 185-5 S + 3 '6 U 14 -6 V = E 93-9 P +446-2 Q 2505-1 R 180 '4 S + 3 *2 U 15M V = E 15 '25 15 '375 15*5 > 86t-6 P +436-3 Q 2450 '5 R 175 '3 S + 2 '9 U 15 '6 V = E 79. '8 P +426-7 Q 2396-8 R 170-4 S + 2-4 U 16-0 V = E 73'3 P +417-3 Q 2344*1 R 165 '6 S + 2 '0 U 16 -3 V = E 15 '625 15 '75 15-875 67-0 P +408-1 Q 2292 *3 R 160 '9 S + 1-6 U 16-7 V = E 60-9 P +399-1 Q 2241-4 R 156-2 S + 1 '3 U 17 '0 V == E 55-3 P +390-4 Q 2191-7 R 151-8 S + 1 '0 U 17 '3 V = E 16 o 16-25 16-5 49 '9 P +381 -9 Q 2142 '9 R 147 '5 S + -8 U 17 *5 V = E 39-8 P +365-3 Q 2048-3 R 139 '0 S + '3 U 17 '9 V = E 30-8 P +349-6 Q 1958-7 R 131-4 S '2 U 18 '3 V = E 16-75 17-0 17-25 22-3 P +334-5 Q 1873 '1 R 123 '8 S '5 U 18 5 V = E 15-2 P +320-0 Q 1791-9 R 117-0 S 0-8 U 18-5 V = E 8 -2 P +306 -3 Q 1714 -4 R 110 '5 S 1 '0 U 18 '6 V = E 17-5 17-75 19-0 2-6 P +293 -3 Q 1641-7 R 104-3 S 1-3 U 18-6 V = E + 3-0 P +280-9 Q 1572-6 R 98-3 S 1-4 U 18-6 V = E + 7 -9 P +269 -4 Q 1507 -4 R 92 '8 S i -6 U is -4 V = E 18 '25 18 -5 18-75 + 12 -7 P +258 -4 Q 1445 '2 R 87 *4 S 1 "J U 18 '4 V = E + 16 -2 P +248 -1 Q 1387 -0 R 82 -9 S 1 -8 U 18 -2 V = E + 20 "3 P +238 -3 Q 1331 '9 R 78 "1 S 1 '9 U 18 '1 V = E 19-0 19'25 19-5 + 23 -3 P +228 -8 Q 1280 -0 R ?4 -1 S 1 '8 U 18 '0 V = E + 26-6 P +220-1 Q 1230-3 R 69-8 S 2 '0 U 17 '9 V = E + 29 -i P +211 -9 Q 1183 -7 R 66 >4 S 2 -4 U 17 '6 V = E 19 75 g + 31-8 P +204-0 Q 1139-1 R 62-5 S 2'2 U 17'6 V = E ^^ ." '' r^-"**". - ' ' " " "-' . 'J-tJ--^-. . . ^ S. at Us appearance in the Years 1835 fy 1836. 251 TABLE XL- -continued. Date. Equations of Condition dependent upon Declinations. 1835. a n n Oct. 13 *375 + 450-7 p 172-3 Q + 962*9 R + 121M S + 21 -4 U + 65," 3 V = E 1 13-5 + 449*6 p 130-0 Q + 1012*0 R + 124-9 S + 22 -3 U + 68*1 V = E 1 13*625 + 447-6 p 187-3 Q + 1053*6 R + 127-2 S + 23*2 u + 70-9 V =r E' 13*75 + 444-5 p 193-7 Q + 1088 *0 R + 129-8 S + 24*0 u + 73 '6 V = E 1 13*873 + 440-3 p 198-8 Q + 1115 *6 R + 131-1 S + 24*6 u + 76-1 V S3 E' 14*0 + 435-5 p 202-8 Q + 1187*0 R + 131 '9 S + 25-2 u + 78-5 v = E f 14123 + 430-2 p 205-8 Q + 115* -1 R + 132-5 S + 26-1 u + 80-9 v = E f 14-25 + 424 -2 p 207 -9 Q + 1163 9 R + 132 -6 S + 27-0 u + 83-2 V = E 7 14*375 + 417-3 p 209*4 Q + 1169*6 R + 132-1 S + 27*5 u + 85/3 V = E 7 14-5 + 410*0 p 210-2 Q + 1171-0 R + 131-2 S + 28*0 u + 87*3 V = E' 14 -623 + 402 -8 p 209-8 Q + 1168-6 R + 130-2 S + 28-7 u + 89*2 V = E 7 14-75 + 395-4 p 208 -6 Q + 1162*6 R + 123-9,S + 29-3 u + 91-0 V ss E 7 14*875 + 337-6 p 206 -6 Q + 1153 -a R + 127-4 S + 29-7 u + 92*5 V =8 E 7 15-0 + 379* p 203 -9 Q + 1141 -4 R + 125-6 S + 30*1 u + 93*9 V r= E 7 15-125 + 371 '6 p 201 -0 Q + 1127-4 R + 123-8 S + 30*6 u + 95-3 V =5 E 7 15-25 + 363-4 p *-i97'9 Q + 1111-5 R + 121-8 S + 31*1 u + 96*5 V rs E 7 15-375 + 354-9 p 194-5 Q A, 1093-5 R + 119-4 S + 31 *3 u + 97*5 V = E 7 15-5 + 346-5 p 190-9 Q t 1074*1 R + 116-9 S + 31-4 u + 98*3 V = E 7 15*625 + 338-2 p 187 -o Q + 1054 *0 R + 114-6 S + 31*7 u + 99*1 v = E 7 15*75 + 330-0 p 189*9 Q + 1032 -9 R + 112-3 S + 31*9 u + 99*8 V = E 7 15*875 + 321 -6 p 173-8 Q + 1010*9. R + 109-6 S + 31-9 u + 100*3 V = E 1 16 '0 + 313-2 p -174-6Q + 988-0 R + 106-9 S + 31*9 u + 100*7 V S3, E 7 16-25 + 297-3 p 165 '9 Q + 941 *0 R + 101-8 S + 32-1 u + 101*5 V = E 7 16*5 + 281*7 p 157-3 Q + 892-8 R + 96 -6 S + 31 -8 u + 101*7 V E 7 16*75 + 266-9 p 149*0 Q + 843*8 R + 91 -6 S + 31-9 u + 101*8 V S3. E 7 17'0 + 252-5 p s141 *0 Q + 795-4 R + 86-5 S + 31-5 u + 101 -5 V = E 7 17-25 + 239-4 p 132-9 Q + 748*8 R + 81 -9 S + 31-5 u + 101-2 V S3, E' 17*5 + 226-3 p 125*4 Q + 703-6 R + 77'2 S + 30*6 u + 100*4 V S3 E 7 17-75 + 214-4 p 117-6 Q + 661 -0 R + 73 -o S + 30-4 u + 99-7 V = E 7 18-0 + 202*8 p 110-1 Q + 620-1 R + 68 -6 S + 29-7 u + 98-7 V S3. E 7 18 25 + 192*3 p 102*9 Q + 581-7 R + 64 -8 3 + 29-2 u + 97-6 Vra E 7 18-5 + 182*2 p 9* "3 Q + 345-0 R + 61 -0 S + 28*4 u + 96*4 V = E 7 18-75 + 172-9 p 89-9 Q + 510-4 R + 57-6 S + 27*9 u + 95-3 V *==. E 7 19-0 + 164 -2 p 84-0 Q + 477-8 R + 34-3 S + 27-4 u + 94-2 V = E 7 19-25 + 155-9 p 78 -6 Q + 446*8 R + si -a S + 26*7 u + 92*8 V =: E 7 19-5 + 148-1 p 73-7 Q + 417-7 R + 48-2 S + 26*1 u + 91-5 V S3 E 7 19-/5 + 141* 69*1 Q + 390*6 ft + 45 '6 S + 25*5 u + 90-1 V = E 7 6 p - ft 9 252 On the Elements of the Orlit of Halley's Comet, TABLE XI . continued. Date. Equations of Condition dependent upon Right Ascensions. 1835. Oct. 19-75 20-0 20-25 // + 31 -8 + 33 -8 + 35*9 P P P If + 204 -0 + 196-3 + 189-3 Q 1139-1 Q 1097 -5 Q 1057-5 R R R n 62-5 S 59-5 S 56-2 S II 2 *2 2-6 2-6 U U U II 17-6 V 17-6 V 17-4 V = E = E = E 20'5 + 37 '9 P + 182-6 Q 1019-4 R- 53*2 S 2 *4 U - 17-0 V = E 20-75 + 39-8 P + 176-2 Q- 983*4 R 50-1 S 2-3 U 16-6 V = E 21 *0 + 41 *2 P + 170-1 Q- 949-8 R- 47-5 S 2-4 U - 16-5 V = E 21*25 + 42-8 P + 164-3 Q- 916-9 R 44*7 S 2-1 U - 16-3 V = E 21*5 + 44 *0 P + 158-9 Q- 886*4 R- 42*4 S 2-4 U - 16-0 V = E 21 *75 + 45*5 P + 153-6 Q- 856*9 R 39*8 S 2-3 U - 15-9 V = E 22*0 + 46-4 P + 149-0 Q- 829*0 R 37-9 S ,2-5 U 15-7 V = E 22*25 + 47*9 P + 144*4 Q- 802*0 R 35-6 S 2*1 U 15-5 V = E 22*5 + 48*3 P + 139*9 Q- 777-0 R- 34*0 3 2 *4 U 15-3 V = E 22*75 + 49-6 & + 135-5 Q~ 752*8 R- 31*7 S 2*2 U 15-1 V = E 23*0 + 50*3 P + 131-4 Q- 729-9 R 30-2 S 2*2 U 14*8 V =2 E 23'25 + 61 *2 P + 127*2 Q- 707-8 R 28-2 S 2*0 U - 14-6 V = E 23-5 + 51 *6 P + 123 -4 Q- 687 o R 26*8 S 2*1 U - 14-4 V = E 23*75 + 52*6 P + 120*2 Q- 666-7 R 24 '9 S 1*9 U - 14-1 V = E 24*0 + 53*0 P + 116*6 Q- 647-6 R 23*6 S 2*1 U 14-0 V = E 24*25 + 53*8 P + 113-2 Q- 629-0 R- 22*0 S I *8 U 14-0 V = E 24*5 + 54*1 P + 110-2 Q- 611-8 R 20*9 S 2*2 U 13-9 V = E 24*75 + 54*9 P + 107-1 Q- 594*7 R- 19-2 S 1-9 U - 13-6 V = E 25*0 + 55 M P + 104*2 Q- 578*8 R 18*3 S 2 *2 U - 13-5 V = E 25*25 + 55-7 P + 101. *5 Q- 562*8 R 16*8 S 1 -8 U 13-3 V = E 25-5 + 56 -0 P + 98*8 Q- 548*3 15*9 S 2-1 U 13-1 V = E 25*75 + 56*6 P + 96-0 Q- 533 -8 R 14*4 S 1 -8 U - 13-0 V = E 26 *o + 66-7 P + 93-4 Q- 520*4 R 13*6 S 2-1 U 12-9 V = E 26-25 + 57*4 P + 90-9 Q- 507*1 R 12-3 S 1-7 U - 12-4 V r= E 26-5 + 57*3 P + 88*5 Q- 494-8 R- 11-8 S 2-0 U 12-6 V = E 26-75 + 58*0 P + 86*3 Q- 482-3 R 10-5 S 1-7 U 12-4 V = E 27-0 + 58*1 P + 84*3 Q- 470-8 R- 9*8 S 1-9 u- 12 -3 V = E 27*25 + 58*7 P + 82*4 Q- 459-0 R 8*6 S 1-5 u 11-9 V = E 27-5 + 58-5 P + 80*4 Q- 448-6 R 8*1 S 1-9 U - 12-0 V = E 27*75 + 59-2 P + 78-7 Q- 437-7 R 6*9 S 1-6 U 11-5 V = E ' 28-0 + 59-1 P + 77-1 Q- 427*9 R 6-4 S 1-8 U n-6 V =r E 28 '25 + 59-8 P + 75-6 Q- 417-7 R 5-28 1 -2 u- 11-2 V == E 28*5 + 59-4 P + 73-6 Q- 409-0 R 5*0 S 1*9 u 11*4 V s E 29*5 i== + 60 -4 .M P MB + 67-5 ' Q- 375-4 R- 2-28 1*6 U - 10'8 V = E at its appearance in the Years 1835 fy 1836. 253 TABLE XI. continued. Date. Equations of Condition dependent upon Declinations. 1835. Oct. 19'75 20 '0 20 '25 20 '5 20 -75 21-0 21 *25 21 '5 21 '75 22 '0 22-25 22 '5 22 '75 23'0 23-25 23'5 23-75 24-0 24-25 24-5 24 '75 25-0 25 -25 25'5 25-75 26 -0 26 '25 26-5 26-75 27 -o 27-25 27-5 27-75 28 -0 28 '25 28 '5 29 5 // // // // // // + 141-6 P 69-1 Q + 390-6 R +45-6 S +25-5 U + 90 *i V + 134-0 P 64-7 Q + 364 '7 R +43-0 S +24 '7 U + 88 '8 V. + 127 -8 P 60 '7 Q + 340 -8 R + 40 '8 S + 24 '2 U + 87 '4 V + 121-8 P + 116-3 P + 110-9 P + 106-3 P + 101-5 P + 97 '4 P + 93 -1 P + 89 -3 P + 85 -6 P + 82 -3 P + 79 -0 P + 76 "2 P + 73 '2 P + 70 '5 P + 67 -6 P + 65 -6 P + 63 -3 P + 61-1 P + 59 -0 P + 57-1 P + 55 -3 P + 53 -6 P + 51-9 P + 50 -3 P + 48 -6 P + 47 -4 P + 46-1 P + 44 -8 P + 43 -5 P + 42 -3 P + 41-1 P + 40-1 P + 39 -0 P E' E' E 7 E' E' E' E' E' E' E' E' E' E' E' E' E' E 7 E' E' 57-0 Q + 318*0 R +38*5 S +23*3 U + 86 -0 V = 53-3 Q + 297-1 R + 36-5 S +22-8 U + 84 '6 V = 49-7 Q + 277-4 R +34-3 S +21-9 U + 83*8 V = 46-2 Q +259-4 R + 32*8 S +21*5 U + 82 -1 V = 43-0 Q + 242*3 R + 30-9 S +20-8 U + 80 '8 V = 39-8 Q + 226*3 R +29 '5 S +20-4 U + 79-6 V = 37-0 Q + 211*4 R + 27*8 S +19-7 U + 78 *3 V = 34-3 Q + 197-6 R + 26-6 S +19-2 U + 77-3 V = 31-9 Q +184-3 R + 25*1 S +18-6 U + 75 '9 V = 29 -9 Q + 172 -o R + 23 *9 S +18 -i U + 74 '7 V = 27-9 Q + 160-3 R +22-8 S +17-5 U + 73-6 V = 26-0 Q + 149-5 R +.21-8 S +17-1 U + 72-6 V = 24*3 Q + 139*2 R +.20-7 S +16-5 U + 71'5 V = 22-7 Q + 129-5 R + 19 '7 S +16-0 U + 70-3 V = 21 -2 Q + 120 -3 R + 18 -8 S + 15 -5 U + 69 '3 V = 19-2 Q + 111-8 R + 18-1 S +15-2 U + 68-3 V = 17-9 Q + 103-7 R + 17-2 S +14-6 U + 67-3 V = 16-6 Q + 96-3 R + 16-5 S +14-3 U + 66-4 V = 15-3 Q + 89'3 R + 15-7 S +13-8 U + 65 *4 V = 14-1 Q + 82-8 R + 15-1 S +13-4 U + 64 '3 V = is-i Q + 76'7 R + 14-6 S +13-0 U + 63-7 V = 12-2 Q + 70-7 R + H-o S +12-6 U + 62-7 V = 11 -4 Q + 65 -2 R + 13 -4 S + 12 -2 U + 6l '9 V = 10-6 Q + 59-8 R + 12-9 S +11-8 U + 61-0 V = 10 -0 Q + 54 -7 R + 12 -2 S + 11 -3 U + 60 -0 V . == 9 -0 Q + 50 -3 R + 12 -0 S + 11 -2 U + 59 -5 V = 8 -1 Q + 45 '9 R + 11 -6 S + 10 -8 U + 58 '7 V = 7 -5 Q + 4i -8 R + 11 -i S + 10 -4 U + 57 -9 V = 6-7 Q + 37-9 R + 10-7 S +10-1 U + 57-2 V = 6 -i Q + 34 -3 R + 10 -4 S + 9 '7 U + 56 -4 V = 5-4Q+ 30-7 R + 9-9 S + 9'3 U + 55-7 V = 4 -7 Q + 27 -6 R + 9 '7 S + 9 -2 U + 55 -o V = r- 4 -1 Q + 24 -3 R + 9 '3 S + 8 '7 U + 53 -8 V rr + 35 -4 P 2 -1 Q + 13 -4 R + 8 -2 S + 7 '6 U + 51 -7 V = E A E' E f E' E' E' E' E 1 E' E' E' E' E 1 E' E' E' 254 On the Elements of the Orbit of Halley's Comet, TABLE XI . continued. Date. Equations of Condition dependent upon Right Ascensions. 1835. w n n II II Oct. 29 -5 4- 60-4 P 4- 67-5 Q 375 -4 R 2-28 -6 U 10-8 V " E 30 '5 4- 61-2 P4- 62-2 Q 345*9 R + 0-3 S -4 U - 10-4 V sr E 31-5 4- 6i -9 P 4- 57-4 Q 320*7 R + 2-4 S -4 U 9-9 V = E Nov. 1-5 4- 6e-5 P 4- 53 -8 Q 298*8 R 4- 4-3 S -3 U - 9-5 V 17 2-5 + 63-0 P -f 50-2 Q - 279*9 R 4- 6'0 S -o u 9'2 V = E 3-5 4- 68-7 P 4- 47 '5 Q - 263-3 R + 7-6 S -0 u 8-7 V E 4-5 4- 64-2 P4- 44-8 Q 249*8 R + 8*9 S 1 *0 u 8-2 V E 5-5 4- 64-7 P + 42-8 Q 2S/-8 R + C 0-8 u 7-7 V =z E 6-5 4- 64-9 P 4- 41-0 Q 228*2 R 4- 11-1 S 0-8 u 7'5 V = E 7'5 4- 65-6 P 4- 39'5 Q 220*1 R 4- 12-3 S 0-8 u- 7-3 V = E 8-5 4- 66-1 P -f 33-2 Q 2] 3 -5 R 4- 13-3 S 0-7 u 6-9 V = E 9'5 + 66-5 P 4- 37-5 Q 208 *5 R 4- 14-1 S 0-6 u 6-7 V = E 10-5 4- 66-8 P 4- 36 -7 Q 204 *9 R 4- 15*0 S 0-6 u 6-3 V = E 11-5 4- 67-0 P4- 36-1 Q 202 -2 R 4- 15-6 S 0-4 u 6-1 V = E 12-5 4- 67*7 P 4- 35-8 Q 200*6 R 4- 16-8 S 0-5 u - 5-9 V as E 13-5 + 67-7 P4- 35-8 Q * 200-0 R + 17-0 S o-i u 5-5 V = E 14-5 + 68-0 P 4- 36-1 Q 200-3 R 4- 17-6 S 0-4 u 5-4 V s= E 15-5 4- 68-1 P + 36-0 Q i 201 -2 R 4- 18*3 S 0-2 u - 4-9 V = E 16-5 4- 68-0 P 4- 36-1 Q 203*1 R + 18-7 S 0-3 u - 4-9 V = E 17*5 4- 68-1 P + 36 -7 Q 205 -3 R 4- 19 '0 S 0-2 u 4-5 V r E 18*5 4- 68-1 P -f 37-2 Q 208 -1 R 4- 19'9 S O'l u- 4-3 V !T E 19-5 4- 68*0 P 4- 37'7 Q 211 -2 R 4- 20-2 S * __ 4-0 V "P 20-5 4- 67-9 P 4- 38-2 Q 214-9 R 4- 21*1 S o-i u- 3-8 V = E 21'5 4- 67'6 P 4- 38 '8 Q 218 -9 R 4- 20*9 S o-i u- 3-7 V s E 22-5 4- 67-3 P 4- 39 '3 Q. 222 '9 R + 21-2 S 0-2 u 3-3 V = E 23-5 + 67-0 P 4- 40-3 Q 226 '9 R 4- 21-7 S * 3'2 V = E 24-5 4- 66-7 P + 41-2 Q 831/3 R 4- 22-0 S 4-0-2 u - 3-1 V = E 25-5 4- 66-4 P4- 42 '0 Q 235-7 R + 22-3 S 4- o-i u - 2-9 V = E 26-5 4- 65-8 P 4- 42-6 Q 240-2 R 4- 22-6 S * 2-8 V = E 27-5 4- 65-4 P 4- 43-4 Q 244 *1 R + 22*9 S * 2*6 V = E 28-5 4- 64-9 P 4- 44 X) Q - 248 '7 R 4- 23-2 S * _ 2-4 V = E 29-5 4- 64-4 P 4- 44 -7 Q 252-7 R 4- 23-5 S + o-i u - 2-2 V rr E 30-5 + 63-9 P + 45-4 Q 36 r 6-9 * + 23-8 S 4-0-1 u 2-1 V = E Dec. 1-5 4- 63-5 P + 46-3 Q 261 -o R 4- 24-3 S 4- 0-2 u - 1-8 V = E 2*5 4- 62 -9 P 4- 47-1 Q 264-7 R 4- 24-3 S 4- o-i u - 1-7 V = E 3-5 4- 62-2 P 4- 47 '7 Q 268-6 R 4- 24-6 S * . 1-6 V = E 4-i + 61-7 P 4- 48-4 Q 272-7 R 4- 24-8 S 4-0-2 u - 1-4 V s= E at Its appearance in the Years 1835 fy 1836. 255 TABLE XI. continued. Date. Equations of Condition dependent upon Decimations. 1835. u fl a a Oct. 29 -5 + 35-4 P 2-1 Q 4- 13 -4 R 4- 8-2 S 4* 7 *6 u + 5i-7 V =r EJ 30-5 4- 32-3 P o-s Q 4- 4-6 R 4- 7-4 S 4-6-6 U 4- 49-3 V C"""t Ft 31-5 + 29-6 P 4- 0-5 Q 2-6 R 4- 6-7 S 4-5-6 U + 47-1 V s= E' Nov. i *5 4- 27'4 P 4- 1-6 Q 8-4 R + 6-1 S 4- 4-7 U + 44-9 V = E' 2-5 4- 25-5 P 4- 2-5 Q 13-1 R 4- 5-7 S 4- 4-1 U 4- 43-1 V rr E' 3 '5 4- 23 '7 P 4- 3-0 Q 17-1 R + 5-2 S 4- 3-i U 4- 41-2 V C5 E' 4-5 4- 22-4 P 4- 3-7 Q 20'4 R + 4-9 S 4-2-5 U 4- 39-6 V cs E ; 5-5 21-2 P 4- 4-2 Q 23-1 R 4- 4-78 4- 1 *9 U + 38 '0 V ns E' 6-5 + 19 '7 P 4-6Q - 25-6 R 4- 4-6 S 4- 1-2 U 4- 36-4 V E' 7-5 + 19-1 P 4- 5-0 Q 27-6 R 4- 4-3 S 4- 0-7 U 4- 35-0 V = E' 8-5 4. 18-3 P 4- 5-3 Q 29'4 R 4- 4-2 S 4- o-i U 4- 33 '6 V =5 E' 9'5 + 17'5 P 4- 5'5 Q 31-1 R 4- 4-0 S 0-4 U4- 32'3 V S3 E' 10-5 + 16-8 P 4- 5-8Q- 32 -6 R 4- 3-9 S 0-9 U 4- 31 -0 V 5= E' 11 -5 4- 16-0 P 4* 5-8 Q^ 34-1 R 4- 3-7 S 1 -5 U 4- 29-6 V S3 E' 12 '5 + 15 '6 P 4- 6-2 Q . 35'0 R + 3 -a s 1-7 U 4- 28-6 V =3 E' 13-5 + 15-1 P 4- 6-4 Q 36-3 R 4- 3-8 S 1-8 U 4- 27-5 V S3 E' 14-5 4- 14-6 P 4- 6-8 Q 37-3 R + 3-8 S 2'5 U 4- 26 -4 V S3 E' 15 '5 14-2 P 4- 6 -8 Q 3d "2 R + 3-8 S 2-9 U 4- 25 -3 V S3 E' 16 '5 4- 13 -9 P 4- 7-1 Q - 39-3 R 4- 3-9 S 3-1 U4- 24-3 V =3 E ; 17'5 4- 13-6 P 4- 7 ; 3Q 40-0 R 4- 3-9 S 3-4 U 4- 23-3 V S3 E' 18 '5 + 13 "2 P 4- 7'4 Q- 41'2 R 4- 3* S 3-8 U 4- 22'3 V S3 E' 19'5 + 12 -a P 4- 7-5 Q 42-2 R 4- 3-8 S 4-1 U 4- 21-3 V 23 E' 20-5 4- 12 '4 P 4- 7'7 Q~ 43-2 R 4- 3 -a S 4*4 u + 20 % V S3 E' 81 -5- -f 1'2 ! P 4- 7-8 Q 44-1 R 4- 3-) S 47 U 4- 19-3 V S3 E' 22 '5 4- 11 "9 P 4- 7'7 Q- 44-7 R + 3-8 S 4-6 U 4- 18 'i V =s E' 23-5 4. 11 -6 P 4- 8-2 Q 45-7 R 4- 3-9 S 5-1 U 4- 17 * V S3 E' 24'5 4- 11-3 P 4- 8-3 Q 46-6 R 4- 3-3 S 5-4 U 4- !* V S3 E' 25-5 + 11-0 P 4- 8'5 Q 47-4 R 4- 3-9 S 5-6 U 4- 157V = E' 26-5 _l_ 10-7 P 4- 8-4 Q 48-3 R 4- 3-98 5-8 U 4- 14-8 V 5= E' 27'5 4- 10 -5 P 4- 8-7 Q 48-9 R 4- 3-98 -6-1 U + 14'* V = E ; 28-5 + 10-5 P 4- 8-8 Q 49-7 R 4- 4-0 S 6-2 U 4- 13 -1 V = E' 29-5 + 10-0 P 4- 8-9 Q 50'3 R 4- 4-0 S 6-4 U 4- 12-3 V S3 E' 30-5 + 9-8 P 4- 9-1 Q - 51 -0 R + 4-1 S 6-6 U 4- u* V S3 E 7 Dec. i -5 4- 9'6 P 4- 9-2 Q - 51 -8 R 4- 4-2 S 6-8 U 4- 10-7 V S3 E' 2-5 4- 9'4P 4- 9'3 Q - 52-4 R 4- 4-1 S 7'0 U 4- 9-9 V S3 E 7 3-5 9-1 P 4- 9>4Q- 53*1 R 4- 4-1 S 7 '2 U4- 9-0 V = E' 4-5 4- 8-9 P 4- 9'5 Q- 53-8 R 4- 4-2 S 7-2 U 4- 8-3 V = E/ 256 On the Elements of the Orbit of Halleys Comet, TABLE XI . continued. Date. Equations of Condition dependent upon Right Ascensions. 1835. // II N It a Dec. 4-5 + 61-7 P + 48-4 Q- 272-7 R + 24-8 S 4-0-2 U 1-4 V = E 5-5 4- 6l -2 P + 49-3 Q- 275-4 R + 25-2 S 4-0-2 U 1-1 V = E 6-5 4- 60-6 P + 49-5 Q- 279-1 R + 25-4 S 4-0-1 U 1-1 V = E 7-5 + 59'9 P + 50'1 Q- 282-7 R + 25-6 S 4-0-1 U i-o V T? 8-5 + 59-5 P + 50-8 Q- 285-6 R + 25-9 S 4-0-1 u 0-8 V = E 9'5 + 58-9 P + 51 -5 Q- 289-1 R + 26-1 S 4- o-i u 0-7 V = E 10'5 4- 58-3 P + 51 '6 Q- 292-1 R + 26-3 S 4-0-1 U ~ 0-7 V = E 11-5 + 57*9 P + 52-4 Q- 295 -1 R + 26-6 S 4-0-2 U 0-5 V = E 12 '5 + 57'5 P + 52-7 Q- 297'7 R + 26-8 S 4-0-2 u- 0-3 V TJ 1 13*5 + 56-9 P + 53 '3 Q- 300-6 R 4- 27 '1 S 4- o-i u 0'3 V = E 14-5 4- 56-5 P + 54-0 Q- 303-5 R + 27-3 S 4-0*2 u o-i V = E 15 '5 + 55-9 P + 54*4 Q- 306-1 R + 27-5 S 4-0'2 u * TT 16-5 + 55-5 P + 64'7 Q- 308-7 R + 27-8 S 4- o-i u + o-i V = E 17'5 + 55-1 P + 55 '4 Q- 311 -2 R + 28-1 S 4-0-2 U 4- 0-3 V = E 18 -5 + 54-7 P + 56 -0 Q- 313-6 R + 28*3 S 4- o-i u + 0-3 V = E 19-5 + 54-2 P + 56-6 Q- 316-6 R + 28*4 S * + 0-4 V = E 20-5 4- 53-9 P + 56-8 Q- 318 '9 R + 28-8 S * _J. 0'5 V = E 21 -5 + 53-5 P + 57-0 Q- 321-9 R + 29*0 S * + 0-6 V = E 22-5 + 52 '9 P + 67'3 Q- 324-2 R + 29-1 S 0-3 u + 0-4 V ~ E 23-5 4- 52-9 P + 58*3 Q- 326-6 R + 29-6 S * 0-7 V = E 24-5 4- 52-5 P + 59-0 Q- 328 -9 R + 29'9 S 4- o-i u + 0-9 V = E 25-5 + 52'2 P + 58*9 Q- 331 -5 R + 30-1 S + o-i u + 1-1 V = E 26-5 + 51-9 P + 59'7 Q- 334-1 R + 30-5 S * + i-o V = E 27'5 + 61-6 P + 60-0 Q- 336 -7 R + 30-7 S * 1-1 V = E 28*5 4- 51*3 P + 60-5 Q- 339-2 R + 31*0 S O'l u + 1-2 V = E 29 '5 4- 51 ! P + 61 -o Q- 341 -8 R + 31-4 S o-i U 4- 1-3 V = E 30-5 4- 50-9 P + 61-5 Q- 345 -2 R + 31-7 S o-i u + 1-4 V = E 31-5 + 50-7 P + 62-3 Q- 347-6 R + 32 '0 S * + 1-5 V = E 1836. Jan. i -5 + 50'4 P + 62-0 Q- 351 -2 R + 32'3 S o-i U 4- 5 V = E 2-5 4- 50-3 P + 62-6 Q- 353-5 R + 32-6 S 0-2 U + 6 V = E 3-5 4- 50-1 P + 63-6 Q- 356 -0 R + 33'0 S 0-2 U + 7V = E 4-5 4- 49-9 P + 63-7 Q- 359 '5 R4- 33-3 S 0-2 U + 8 V =r E 5-5 + 49-8 P + 65-0 Q- 362 -o R + 33-7 S 0-2 u + 8V = E 6-5 4- 49'7 P + 65-2 Q- 365-8 R + 34-1 S o-i U + 2-0 V = E 7 '5 + 49-5 P + 65-6 Q- 368 '6 R + 34-5 S 0-3 U 4- 2-0 V = E 8 -5 4- 49'4 P + 65-7 Q- 372-4 R + 34-9 S 0'3 U + 1-9 V = E 9'5 + 49-3 P + 67-1 Q- 375 -1 R + 35-3 S 0-3 U 4- 2-1 V = E at its appearance in the Years 1835 # 1836. 257 TABLE XL continued. Date. Equations of Condition dependent upon Declinations. 1835. Dec. 4 -5 4 8-9P 4 9'5 Q 53'8 R 4 4-28 7-2 U 4 81 V E 7 5-5 4 8'8 P 4 9'8 Q 53 '5 R4 43 S 7'3 U 4 7-5 V : E 7 6-5 4 8'5 P 4 9'8 Q 55 '0 R 4 4'3 S 7'6 U 4 6-7 V = E 7 7-5 4 8'4 P 4- 9'9 Q 55-5 R4- 4'4 S 7*7 U 4 6-0 V E 7 8 '5 4 8'2 P 4 10 o Q 56 ! R 4 4'5 S 7'9 U 4 5-3 V r- E 7 9 '5 4 8-1 P 4 10'2 Q - 56-7 R4 4*4 8 8'0 U 4 4-5 V !"** E 7 10 '5 4 7-8 P 4 10*1 Q 57 '7 Ri T 4 '5 S 8 '2 U + 3 7 V - E' 11 *5 4 7'8 P 4 10 '4 Q 57'8 R 4 4-6 S 8 '3 U 4 3-1 V = E 7 12-5 4 7'6 P -f 10-5 Q 58 '4 R 4 4 7 S 8*4 U 4 2-4 V rs E 7 13-5 4 7'4 P + 10-6 Q 59 '1 R 4 4-7 S 8'6 U + 1-6 V = E 7 14*5 4 7'3 P 4 10-7 Q ~ 59'7 R 4 4-78 8-7 U 4 0-9 V : E' 15'5 4 7-i P 4 io-7 Q 60 '2 R4 4- 9 S 8 '8 U + o-i V f E 7 16-5 4 7-o P 4 10-9 Q 60 '7 R 4 5'1 S 9*0 U - 0-6 V = E 7 17-5 4 6 8 P 4 11-0 Q 61 5 R4 5'0 S 9'1 U 1-3 V r" E ; 18'5 4 6 -8 P 4 11-2 Q 62*0 R 4 5'1 S 9'2 U 2-0 V ~ E 7 19'5 4 6-6 P 4 11'3 Q 62*6 R4 6'2 S 9*3 U 2-6 V . E 7 20'5 4. 6-5 P 4 11-4 Q 63-2 R 4 5'2 S 9'5 U 3'3 V = E 7 21-5 4- 6-4 P 4 11-5 Q 64 '0 R 4 5'4 S 9'5 U 4-0 V = E 7 22 '5 + 6-0 P 4 11 '4 Q 64-8 R 4 5-28 *r-iO*0 U 5-0 V ... E 7 23'5 4 6-1 P 4 n-7 Q 65'3 R 4- 5-4 S 9'9 U 5'4 V ~ E 7 24-5 + 6-1 P 4 12-1 Q 65'8 R4 5'6S 10-1 U 6-1 V ^* E 7 25*5 4 6-0 P 4 12'0 Q 66*4 R4- 5-78 10 '0 U 6-8 V = E 7 26 '5 4 5'8 P 4 12-1 Q 67-2 R 4 5- 9 S 10-2 U 7-5 V ~ E 7 27-5 4 s-7 P 4 12-3 Q 67-6 R 4- 6-0 S 10-3 U 8-1 V T*** E 7 28 '5 4 5-sP 4- 12-3 Q 68'5 R 4 6-0 S 10'5 U - 9-0 V ~ E 7 29'5 4 5-4 P 4- 12'4 Q 69-2 R 4 6-28 10 '6 U 9 . 7 v -s E 7 30-5 4 5-4 P 4 12-6 Q 69-9 R4- 6-3 S 10 -7 U 10-3 V = E 7 31 -5 4 5-0 P 4 12-7 Q 70'6 R 4 6-38 10 '8 U - 11-0 V . E 7 1836. Jan. i '5 4 6'2 P 4 13-0 Q 71-1 R + 6*5 S 10-9 U 11-7 V r= E 7 2 '5 4 5-0 P 4 12-9 Q 72-0 R 4 6-5 S 11 -o U 12-5 V r~* E 7 3-5 4 5-1 P 4 13-3 Q 72-4 R 4- 6-9 S 11 -0 U - 13-0 V E 7 4-5 4 4-9 P 4 13-2 Q 73 '3 R 4 6-98 11 '2 U 13 -9 V E 7 5'5 4 4-7 P 4 13-4 Q 73-9 R 4 7-0 S 11 '5 U 14-6 V = E 7 6 '5 + 4-6 P 4 13-5 Q 74-7 R4 7-1 S 11-6 U 15-4 V - E 7 7 '5 4 4 -5 P 4 13-6 Q 75'4 R 4 7-28 11 '8 U 16-2 V =r E 7 8 '5 4 4-1 P 4 13-7 Q 76-0 R4 7-48 11 '8 U - 16-8 V ~~ E 7 9 "5 + 4'4 P 4 14 '0 Q 76-6 R 4 7-sS 12'0 U 17-5 V = E' 258 On the Elements of the OMt of Hdleys Comet, TABLE XL continued. Date. Equations of Condition dependent upon Right Ascensions. 1836. // II j n II II Jan. 9 '5 + 49-3 P + 67-1 Q 375-1 R + 35-3 S 0-3 U + 2-1 V == E 10-5 + 49-2 P + 67-9 Q 378 -7 R + 35 '7 S 0'4 U + 2-1 V = E 11 '5. + 49-1 P + 68-7 Q 382-3 R + 36-2 S 0-4 u + 2-1 V E 12-5 + 49-0 P + 68-7 Q 686-8 R + 36-8 S 0-4 u + 2-2 V = E 13-5 + 49 -o P + 69-3 Q 390*7 R + 37-3 S 0-4 u + 2-3 V = E 14-5 + 49-0 P + 70-3 Q 394*8 R + 37-78 0-5 u + 2-5 V = E 15-5 + 49-o P + 70-7 Q 399'1 R + 38-2 S 0-4 u + 2-4 V = E 16-5 + 48-8 P + 71 -2 Q 403 -3 R + 38-8 S 0-4 u + 2-3 V = E 17 '5 + 48-3 P + 72-9 Q 407 -6 R + 39-3 S 0-5 u + 2-5 V 2= E 18-5 + 4-9 P + 73*7 Q 411-3 R + 40-1 S 0-4 u + 2-6 V = E 19-5 + 48 -8 P + 74-2 Q 4l6'7 R + 40-4 S 0-7 u + 2-6 V = E 20-5 + 48 -8 P + 74-6 Q 421 "9 R + 40-1 S 0-6 u + 2-5 V = E 21 -5 + 48'9 P + 75-7 Q 426-9 R + 41-8 S 0*7 u + 2-6 V ZZ2 E 22'5 + 48-8 P + 76-6 Q 431 -9 R + 42-3 S 0-8 u + 2-5 V = E 23-5 + 48*7 P + 77-7 Q 437-5 R + 43-1 S 0-5 u + 2-6 V s= E 24-5 + 48 -8 P + 79-0 Q 443*0 R + 43-7 S 1*1 u + 2-4 V 3= E 25*5 + 49-0 P + 80*4 Q 448 *3 R + 44-7 S 0-9 u + 2-7 V = E 26-5 + 49-0 P + 81 -2 Q 453-8 R + 45*4 S 1-1 u + 2-6 V = E 27-5 + 49 '6 P + 82-0 Q 460-4 R + 46-2 S l -o u + 2-6 V E 28-5 + 49-0 P + 83-1 Q 466 '9 R + 47 -o S 1-0 u + 2-5 V r= E 2$ -5 + 49*0 P + 83-9 Q 473*2 R + 47 -8 S 1-2 u + 2-4 V =s E 30-5 + 49'1 P + 85-4 Q '480 -3 R + 48 *'9 S 1-4 u + 2-5 V ss E 31-5 + 49-3 P + 86-4 Q 487-4 R + 49-7 S 1-3 u + 2-4 V = E 1*5 + 49-3 P + 87-6 Q 493-3 R + 50-9 S 1-3 u + 2-5 V s E 2-5 + 49-2 P + 89-3 Q 501-2 R + 51*6 S 1 "7 u + 2-2 V = E 3-5 + 49'3 P + 91 -1 Q 507 '3 R + 52*7 S 1 -5 u + 2-2 V zzz E 4-5 + 49'8 P + 91-5 Q 516-2 R + 53-7 S I'/ u + 2-1 V z E 5-5 + 49-3 P + 93-7 Q 523 -3 R + 54-8 S 2-1 u + 2-0 V = E 6-5 + 49-4 P + 94-6 Q 531 -5 R + 55-9 S 2-0 u + 1-8 V =5 E 7*5 + 49-3 P + 95-9 Q 539-1 R + 67 '-0 S - 2-2 u + 1-5 V = E 8-5 + 49-4 P + 97-6 Q 548-9 R + 58-3 S 2-2 u + 1-5 V = E 9*5 + 49'4 P + 99'3 Q 556-4 R + 59-5 S 2-5 u + 1-2 V = E 10-5 + 49'3 P + 101 *0 Q 564-8 R + 61-0 S 2-4 u + 1-2 V = E 11-5 + 49-3 P + 101 -7 Q 574 -o R + 62-1 S 2-6 u + 0-9 V = E 12-5 + 49 '3 P + 104-1 Q 582-4 R + 63-4 S 2-8 u + 0-7 V = E 13-5 + 49-2 P + 105-9 Q 591*0 R + 65-0 S 2-9 u + 0-5 V = E 14-5 + 49'0 P + 107-1 Q 600-8 R + 66-0 S 3-1 u + 0-3 V =s E at its appearance in the Years 1835 Sf 1836. 259 TABLE XI . continued. Date. Equations of Condition dependent upon Declinations. 1836. ii II it a ii H Jan. 9*5 4- 4'4 P 4 14-0 Q- 76-6 R + 7-5 S 12 -0 U 17'5 V - E ; 10-5 + 4-2 P 4 14'0 Q- 77'4 R + 7-6 S 12-2 U 18 -3 V =: I* 11'5 4- 4-1 P + 14'1 Q- 78'1 R4- 7'7 S 12-3 U 19-1 V =2 E' 12-5 + 3'9 P 4 14'2 Q~ 78-8 R4- 7'9S 12-4 U 19'9 V =2 E 1 13'5 + 3-9 P 4 14-4 Q- 79'4 R 4 8-1 S 12-5 U 20-6 V = E' 14-5 4- 3-7 P 4 14-5 ft..f 80-0 R 4 8-1 S -12 -9 U 21 '2 V S3 E' 15-5 + 3-5 P + 14 '6 Q~ 80-6 R4- 8-2 S 12-9 U 22 '2 V = E' 16 '5 + 3-4 P + 14-7 Q- 81 '2 R 4 8'4 S 18'0 U 23 '0 V = E' 17'5 + 2-8 P 4 14*9 Q- 81-7 R + 8'8 S 13-1 U 23-8 y . E' 18 '5 4- 3-1 P 4 15-0 Q~ 82-2 R 4- 8-8 S 13 '3 U 24-6 V S=5 E' 19'5 * 3-0 P 4 15 'I Q- 82-7 R + 8-8 S 13-5 U 25'4 V = E ; 20-5 4- 2-9 P 4 15'2 Q~ 83'1 R + 9-0 S 13-8 U 26-3 V = E' 21*5 4- 2-7 P 4 15-2 Q- 83 '4 R4- 9-1 S 13-7 U 27*1 V as E' 22'5 + 2'5 P 4 15*3 Q- 83 '9 R + 9 *2 S ~14'0 U 28 -0 V = E' 23'5 4- 2-4P 4- 15*4 Q- 84-1 R + 9-5 S 14-1 U 28-8 Y = E 7 24-5 + 2-1 P + 15M Q- 84'3 R4- 9-5 S 14-2 U 29-7 V s= E' 25-5 4- i-7P 4- 15-3 Q~ 84'6 R4- 9-4 S 14-6 U 30-8 V = E' 26-5 + 1-7 P 4 15 '5 Q~ 84 4 R4- 9'7 S -14-5 U 31 '5 V = E' 27-5 4- 1-6P 4 15-6 Q~ 84 '4 R + 9-8 S ^14 -7 U 32'4 V = E ; 28 '5 4 1-3 P 4- 15'5 Q- 84*2 R 4- 9'9 S 14-8 U 33'3 V r= E' 29'5 4- 0-9 P 4-15*4 Q~ 84'1 R + 9-9 S 15'0 U 34-4 V SB E 7 30 '5 + 0-8 P + 15-5 Q~ 83-6 R + 10-2 S 15-1 U 35 -2 V = E' 31 -5 + 0-6 P 4- 15-5 Q- 83-0 R + 10-3 S 15-3 U 36-0 V = E' Feb. 1-5 4- 0-3 P + 15-3 Q- 82'5 R 4- 10-2 S 15'5 U 37-2 Va= E' 2'5 * 4- 15-2 Q~ 81-6 R + 10-3 S -15 -7 U 38 '0 V = E ; 3 '5 0-3 P + 15-1 Q~ 80 '6 R4- 10-4 S 15-7 U 39'1 V = E 7 4-5 0-7 P + 14'8 Q- 79'5 R + 10'3 S 16-0 U 40-1 V = E 7 5-5 1-0 P 4- 14-4 Q- 78-4 R4- 10-1 S 16-5 U 41 Y E 7 6-5 1-3 P 4- 14'4 Q- 76-6 R 4- 10-3 S 16-3 U 42-1 V = E 7 7-5 1-7P 4- 141 Q- 75 -o R4- 10-1 S 16-6 U 43 '2 V = E 7 8'5 2-1 P 4 13-6 Q- 72-8 R4- 10 -0 S 16-8 U 44 *3 V SS E 7 9'5 2'4 P 4 13-4 Q- 70-6 R + 10-0 S 16-9 U 45'2 V s= E-' 10 -a 2-8 P + 13 '0 Q~ 68-1 R + 10 -o S 16-9 U 46 '3 V E= E 7 11 '5 __ 3-2 P 4 12*4 Q- 65*5 R + 9'6 S 17-3 U 47-5 V = E 7 12-5 3-6P 4- 11 '8 Q- 62'5 R4- 9-4 S 17-5 U 48-6 V s= E 7 13'* 4'2 P 4 11 '3 Q- 59*0 R4- 9-3 S -17 '5 U 49'5 Y = E 7 14-5 4'5 P 4 10-6 Q~ 55'5 R 4- 9-2 S -17 7 U 50-6 V r= E' 260 On the Elements of the Orbit of Halley's Comet, TABLE XI. continued. Date. Equations of Condition dependent upon Right Ascensions. 1836. // II n a Feb. 14 -5 + 49-0 P Q- 600-8 R + 66-0 S 3-1 u + 0-3 V =r E 15-5 + 49-0 P + 109*0 Q- 6os -7 R + 67-7 S 3-0 u * ^ . -pi 16-5 + 48-7 P + 111 -0 Q- 618-2 R + 69-2 S 3-5 u 0-5 V = E 17-5 + 48 -1 P + 112-7 Q- 628-1 R + 70-7 S 3-5 u - 0-8 V = E 18-5 + 48-4 P + 114-2 Q- 636-5 R + 72-3 S - 3-7 u i-o V = E 19'5 + 48 -0 P + 116-2 Q- 645-1 R + 73-6 S 3-9 u 1-5 V = E 20-5 + 47-9 P + 117'3 Q- 654-5 R + 75-2 c 4-0 u - 1-9 V = E 21'5 P + 119'0 Q- 663-1 R + 76'8 s 4-3 u - 2-4 V = E 22-5 + 47-2 P + 120-8 Q- 671 -o R + 78-4 s - 4'5 u - 2-8 V = E 23-5 + 46-7 P + 122-9 Q- 679-2 R + 79-7 s 4-7 u 3-3 V = E 24-5 + 46-3 P + 124-1 Q- 687 '6 R + 81-3 s 5 -0 u 3-8 V = E 25-5 + 45-8 P + 125-3 Q- 694-9 R + 82-6 s 5'2 u 4-5 V = E 26-5 + 45-2 P + 126 -9 Q- 702-4 R + 84-2 s - 5*2 u - 4-9 V = E 27-5 + 44-7 P + 127-8 Q- 709-1 R + 85-7 s 6-1 u 5-3 V = E 28-5 + 44 '2 P + 129-1 Q- 715-3 R + 87-4 s 6-2 u 5-9 V =s E 29-5 + 43-5 P + 129-9 Q- 721-1 R + 88-6 s 6-4 u 6-4 V = E Mar. 1-5 + 42 -8 P + 131 -2 Q- 726 -s R + 89-9 s - 6-6 u - 7-0 V = E 2-5 + 42 -0 P + 132-1 Q- 731 -5 R + 91-2 s 6-3 u 7 -7V = E 3-5 + 41-2 P + 133-4 Q- 734 -9 R + 92-4 s 6-2 u - 8-1 V = E 4-5 + 40 -3 P + 134-5 Q- 738 -9 R + 93-1 s - 6-6 u 9-0 V =r E 6-5 + 39-7 P + 134-8 Q- 741 -5 R + 94-8 s - 6-5 u 9-2 V = E 6-5 + 38*6 P + 135-5 Q- 742 -9 R + 95-4 s 7-0 u - 10-0 V = E 7-5 + 37*5 P + 135-0 Q- 744 -4 R + 96-2 s - 7-1 u - 10-9 V = E 8-5 + 36 -7 P + 135-1 Q- 745 -3 R + 97*2 s 7-2 u 11-4 V = E 9'5 + 35-7 P + 135-4 Q- 745 -4 R + 98-1 s 7-4 u - 12-0 V = E 10-5 + 34-7 P + 136-5 Q- 743 '9 R + 98-8 g 7-4 u 12-4 V = E 11-5 + 33-6 P + 135 -3 Q- 742-5 R + 99-3 s 7-7 u - 13-2 V T? 12-5 + 32-5 P + 135-0 Q- 740-1 R + 99*7 s 7-8 u 13-8 V ~ E 13-5 + 31-5 P + 134-7 Q- 737 -o R + 100-1 s 8-1 u 14-2 V =r E 14-5 + 30-5 P + 133-8 Q- 733-2 R + 100-2 g 7-9 u - 14-8 V = E 15-5 + 29*4 P + 133-6 Q- 728-5 R + 100-5 S 7-1 u 15-3 V =E 16 '5 + 28-3 P + 132-8 Q- 723-1 R + 100-6 g 7'9 u 15-6 V = E 17-5 + 27-3 P + 131 -4 Q- 717-8 R + 100-5 s 8 -0 u - 16-1 V = E 18 -5 + 26-2 P + 130-8 Q - 711 -2 R + 100-5 s 8-0 u - 16-7 V = E 19-5 + 25 -2 P + 129-7 Q- 704-9 R + 100-2 s 8-2 u 17-1 V = E 20-5 + 24-2 P + 128-5 Q- 697-8 R + 100 -2 s 8 -4 u - 17 -4V == E 21 '5 + 23-2 P + 126-9 Q- 690 -6 R + 99'8 s - 8-1 u 17-9 V =r E at its appearance in the Years 1835 < 1836. 261 TABLE XI . ' continued. Date. Equations of Condition dependent upon Declinations. 1836. ~"(i i II n u w II Feb. 14-5 4 5P + 10-6 Q- 55*5 R + 9-28 17-7 U 50-6 V = E ; 15-5 4 9P + 10-1 Q- 51'4 R + 8-6 S 17-8 U - 51-7 V = E' 16-5 5 3 P + 9-3 Q- 46-6 R + 8-28 18-0 U 52-8 V = E 1 17-5 6 oP + 8 -4 Q- 42 -2 R + 7-98 18-1 u - 53-7 V = E ; 18-5 6 3P + 7-5 Q- 37-5 R + 7-sS 17-8 u 54-9 V =r E 1 19-5 6 8 P + 6-5 Q- 32-1 R + 6-9 S 18-3 u 56-1 V = E' 20*5 """* 7 3 P + 5-6 Q- 26-1 R + 6-48 18 '5 u - 57-2 V r=E' 21 -5 7 8P + 4-5 Q- 19'9 R + 5*8 S 18-6 u 68-2 V = E' 22-5 8 4P + 3-3 Q- 13-6 R + 5-1 S 18-8 u 59-3 V = E' 23*5 "" "" 8 9P + 1 -8 Q~ 7-0 R + 4-2 S 18-9 u 60-6 V = E' 24'5 9 -2 P + 0-9 Q + 0-6 R + 3-58 19 '0 u 61-3 V = E' 25'5 - 9 8 P- 0-4 Q + 8*1 R-f 2*8 8 18 -9 u - 62-2 V = E' 26-5 10 3 P 1-9 Q + 15-9 R + 1-8 S 19-1 u - 63-4 V = E 7 27 -5 10 8 P 3-3 Q + 23 '9 R + 0-98 18-4 u 64-4 V =: E 7 28-5 11 3P- 4-8 Q + 32-1 R * 18-6 u - 65-4 V = E 7 29-5 11 6 P 6-2 Q + 40-7 R 1-1 S 18-5 u 66-2 V B E 7 Mar. i -5 12 1 P- 7-8 Q + 49-6 R- 2-1 S 18 -6 u 67-2 V T?/ JCt 2-5 12 4 P 9-3 Q + 58-6 R- 3-4 S 19 '2 u - 68-0 V T?/ - rj 3-5 12 9P- 10-9 Q + 67-4 Xv ~~~ 4-3 S ^19-2 u 68-7 V B E 7 4-5 13 2 P 12 '8 Q + 76-3 R- 5-7 S 19*4 u 69 -7V = E' 5-5 14 -0 P 14-9 Q + 85 -0 R- 7-3 S 19-7 u - 70-9 V B E 7 6-5 13 7P- 16-1 Q + 94-2 R 7'9 S 19-2 u - 71-2 V = E ; 7'5 14 o P- 17-5 Q + 102-8 R 9-1 S 19 '3 u - 71-9 V B E' 8-5 14 2 P 18'8 Q + 112-0 R- 10-2 S 18 '9 u 72-2 V = E 7 9-5 14 4 P 20-8 Q + 120-2 R 11 '8 S 18 -2 u 73-1 V B E 7 10-5 14 5P 22-6 Q + 128-4 R- 12-8 S 19-0 u 73-6 V = E 7 11-5 14 5 P 23'6 Q + 136-3 R- 13-9 S 18-7 u 74 -i V B E 7 12-5 14 6 P 25-0 Q + 143-8 R 15-1 S 18 '9 u - 74-6 V B E 7 13 '5 14 8 P 26-6 Q + 150*7 R 16-3 S 18 -8 u 75-1 V = E 7 14*5 14 5P - 27-5 Q + 157-8 R- 17-3 S 18-6 u - 75-2 V = E 7 15-5 14 5 P 29-0 Q + 163-8 R 18-4 S 18-5 u 75-7 V B E 7 16-5 14 3P- 30-1 Q + 169-7 R 19'5 S 18-4 u - 76-0 V B E' 17-5 14 1 P 30-8 Q + 175-2 R 20-3 S 18 -3 u 76-0 V B E 7 18 -5 14 o P 32-1 Q + 179-9 R 21-3 S 18-1 u 76-1 V = E 7 19-5 13 8 P 33-0 Q + 184-3 R 22*2 S 18-0 u - 76-4 V = E 7 20-5 13v6 P 33-5 Q + 188-3 R- 23 '0 S 17-8 u - 76-5 V B E 7 21 -5 13 3P - 34-2 Q + 191 -6 R- 23-9 S 17-8 u - 76-6 V = E 7 262 On the Elements of the Orbit of Halletfs Comet, TABLE ILL continued. Date. Equations of Condition dependent upon Right Ascensions. 1836. Mar. 21 -5 23 '5 23'5 24-5 25*5 26 5 27-5 28 -5 29 '5 30 '5 31 '5 + 23-2 P +126-9 Q 690-6 R + 99-8 S 8-1 U 17-9 V = E + 22'3 P +126-1 Q 682-8 R + 99 '3 S 8 '2 U 18 "2 V = E + 21 -3 P +124 '7 Q 674 '4 R + 93 '7 S 8 -0 U 18 '4 V == E + 20 '3 P + 123 -0 Q 666 '2 R + + 19'6 P +121-5 Q 657-4 R + + 18'5 P +120-1 Q - 648-4 R + 98 '3 S 8 ! U 18 -8 V = E 97-9 S 7'8 U 18-8 V = E 97-1 S 8-1 U 19-4 V = E + 17-8 P +118-2 Q 639-6 R + 96-9 S 7-9 U 19*4 V = E + 16*8 P +116-9 Q 630-2 R + 95-7 S 7'9 U ~ 19'7 V = E + 16-0 P +114-9 Q 621-4 R + 94-8 S 7-9 U 19-9 V = E + 15 ! P +113-9 Q 611 -6 R + 94-1 S 7 '9 U 20-3 V r= E + 14-6 P +114 o Q 600-5 R + 93-3 S 7-9 U 20*2 V = E at Its appearance in the Years 1835 < 1836. 263 TABLE XL continued. Date. Equations of Condition dependent upon Declinations. 1836. Mar. 21 -5 22 *5 23-5 24 '5 25 '5 26-5 27*5 28 29 30 '5 31 -5 13 -3 P 34 *2 Q + 191 -6 R 13-0 P - 34'9 Q + 194-6 R 12'6 P 35-3 Q + 196-9 R 12-3 P 35'7 Q + 199-0 R 12 -0 P 36 -1 Q -f 200 -8 R 11 -6 P 36 -4 Q + 201 -5 R 11 '3 P 36 '4 Q + 202 '2 R 11-0 P 36-6 Q + 202-5 R 10-6 P 36-5 Q + 202-5 R 10-3 P 36-3 Q + 201-7 R 9 -3 P 37 -9 Q + 199 '9 R 23 '9 S 17 '8 U 24-3 S 17-6 U 24'9 S 17-4 U 25-6 S 17-3 U 26 '2 S 17 -0 U 26 -6 S 16 -9 U 26 '9 S 16 '7 U 27-1 S 16-1 U 27-6 S 16-4 U 27'8 S l6 -2 U 28 -o S 16 -1 U 76 -6 V = E' 76 -5 V = E' 76 -4 V = E' 76-5 V = E' 76 -3 V = E' 76 -2 V = E' 76 -o V = E' 75-7 V = E' 75 -6 V = E' 75 -3 V = E' 74-9V = E' 265 ON THE PERTURBATIONS OF URANUS. BY J. C. ADAMS, ESQ., M.A., FELLOW OF ST. JOHN'S COLLEGE, CAMBRIDGE ; FELLOW OF THE BOYAL ASTRONOMICAL SOCIETY; AND OF THE CAMBRIDGE PHILOSOPHICAL SOCIETY. (Read before the Royal Astronomical Society, November 13, 1846.) 1. THE irregularities in the motions of Uranus have for a long time engaged the attention of Astronomers. When the path of the planet became approximately known, it was found that, previously to its discovery by Sir W. Herschel in 1781, it had several times been observed as a fixed star by Flamsteed, Bradley, Mayer, and Lemonnier. Although these observations are doubtless very far inferior in accuracy to the modern ones, they must be considered valuable, in consequence of the great extension which they give to the observed arc of the planet's orbit. Bouvard, how- ever, to whom we owe the Tables of Uranus at present in use, found that it was impossible to satisfy these observations, without attributing much larger errors to the modern observations than they admit of, and consequently founded his Tables exclu- sively on the latter. But in a very few years sensible errors began again to show themselves, and though the Tables were formed so recently as 1821, their error at the present time exceeds two minutes of space, and is still rapidly increasing. There appeared, therefore, no longer any sufficient reason for rejecting the ancient observa- tions, especially since, with the exception of Flamsteed's first observation, which is more than twenty years anterior to any of the others, they are mutually confirmatory of each other. 2. Now that the discovery of another planet has confirmed in the most brilliant man- ner the conclusions of analysis, and enabled us with certainty to refer these irregu- larities to their true cause, it is unnecessary for me to enter at length upon the reasons which led me to reject the various other hypotheses which had been formed to account for them. It is sufficient to say, that they all appeared to be very improbable in them- selves, and incapable of being tested by any exact calculation. Some had even supposed that at the great distance of Uranus from the Sun, the law of attraction becomes different from that of the inverse square of the distance. But the law of gravitation was too firmly established for this to be admitted, till every other hypo- thesis had failed, and I felt convinced that in this, as in every previous instance of the kind, the discrepancies which had for a time thrown doubts on the truth of the law, would eventually afford the most striking confirmation of it. 3. My attention was first directed to this subject several years since, by reading Mr. Airy's valuable Report on the recent progress of Astronomy. I find among my 266 On the Perturbations of Uranus. papers the following memorandum, dated July 3, 1841: "Formed a design, in the beginning of this week, of investigating, as soon as possible after taking my degree, the irregularities in the motion of Uranus which are yet unaccounted for ; in order to find whether they may be attributed to the action of an undiscovered planet beyond it, and if possible, thence to determine approximately the elements of its orbit, &c., which would probably lead to its discovery." Accordingly, in 1843, I attempted a first solution of the problem, assuming the orbit to be a circle, with a radius equal to twice the mean distance of Uranus from the Sun. Some assumption as to the mean distance was clearly necessary in the first instance, and Bode's law appeared to render it probable that the above would not be far from the truth. This investigation was founded exclusively on the modern observations, and the errors of the Tables were taken from those given in the Equations of Condition of Bouvard's Tables as far as the year 1821, and subsequently from the observations given in the Astronomische Nachrichten, and from the Cambridge and Greenwich Observations. The result showed that a good general agreement between theory and observation might be obtained ; but the larger differences occurring in years where the observa- tions used were deficient in number, and the Greenwich Planetary Observations being then in process of reduction, I applied to Mr. Airy, through the kind intervention of Professor Challis, for the observations of some years in which the agreement appeared least satisfactory. The Astronomer Royal, in the kindest possible manner, sent me, in February 1844, the results of all the Greenwich Observations of Uranus. 4. Meanwhile the Royal Academy of Sciences of Gottingen had proposed the Theory of Uranus as the subject of their mathematical prize, and although the little time which I could spare from important duties in my college prevented me from attempt- ing the complete examination of the theory, which a competition for the prize would have required, yet this fact, together with the possession of such a valuable series of observations, induced me to undertake a new solution of the problem. I now took into account the most important terms depending on the first power of the eccentricity of the disturbing planet, retaining the same assumption as before with respect to the mean distance. For the modern observations, the errors of the Tables were taken exclusively from the Greenwich Observations as far as the year 1830, with the excep- tion of an observation by Bessel, in 1823; and subsequently from the Cambridge and Greenwich Observations, and those given in various numbers of the Astrono- mische Nachrichten. The errors of the Tables for the ancient Observations were taken from those given in the Equations of Condition of Bouvard's Tables. After obtaining several solutions differing little from each other, by gradually taking into account more and more terms of the series expressing the Perturbations, I communi- cated to Professor Challis, in September 1845, the final values which I had obtained for the mass, heliocentric longitude, and elements of the orbit of the assumed planet. The same results, slightly corrected, I communicated in the following month to the Astronomer Royal. The eccentricity coming out much larger than was probable, and later observations showing that the theory founded on the first hypothesis as to the mean distance, was still sensibly in error, I afterwards repeated my investigation, supposing the mean distance to be about g-Vth part less than before. The result, On the Perturbations of Uranus. 267 which I communicated to Mr. Airy, in the beginning of September of the present year, appeared more satisfactory than my former one, the eccentricity being smaller, and the errors of theory, compared with late observations, being less, and led me to infer that the distance should be still further diminished. 5. In November, 1845, M. Le Verricr presented to the Royal Academy of Sciences at Paris, a very complete and elaborate investigation of the Theory of Uranus, as dis- turbed by the action of Jupiter and Saturn, in which he pointed out several small inequalities which had previously been neglected j and in June, of the present year, he followed up this investigation by a memoir, in which he attributed the residual disturbances to the action of another planet at a distance from the Sun equal to twice that of Uranus, and found a longitude for the new planet agreeing very nearly with the result which I had obtained on the same hypothesis. On the 3 1st of August he presented to the Academy a more complete investigation, in which he determined the mass and the elements of the orbit of the new planet, and also obtained limiting values of the mean distance and heliocentric longitude. I mention these dates merely to show that my results were arrived at independently, and previously to the publica- tion of those of M. Le Verrier, and not with the intention of interfering with his just claims to the honours of the discovery ; for there is no doubt that his researches were first published to the world, and led to the actual discovery of the planet by Dr. Galle, so that the facts stated above cannot detract, in the slightest degree, from the credit due to M. Le Verrier. 6. In order not to have an inconvenient number of equations of condition, I divided the modern observations into groups, each including a period of three years, and as Mr. Airy had shown that the error of the Tabular Radius Vector was sometimes con- siderable, I either selected those observations which were made near opposition, or combined the others in such a manner that the result should be nearly free from the effects of this error. From the observations of each group, the error of the Tables in heliocentric longitude was found, corresponding to the time of mean opposition in the middle year of the group. Thus were formed 21 normal errors of the Tables, cor- responding to as many equidistant periods between 1780 and 1840. The error for 1780 was found by interpolating between the errors of 1781, 1782, and 1783, and those given by the Ancient Observations of 1769 and 1771, and though not entitled to the same weight as the others, cannot, I think, be liable to much uncertainty. In my last calculations, I might have used more recent observations, but in order to obtain the effect due to the change of mean distance, it was necessary that the in- vestigation should be founded on the same elements as before, and the later observa- tions might be used as a test of the theory. 7. In order to satisfy myself that there was no important error in Bouvard's Tables, I recomputed all the principal inequalities produced by the action of Jupiter and Saturn, and found no difference of any consequence except in the equation depending on the mean longitude of Saturn minus twice that of Uranus, the error of which had been already pointed out by Bessel. The principal equation depending on the action of Jupiter, also required correction in consequence of the increased value which has been lately obtained for the mass of that planet. The corrections to be applied to Bouvard's Tables on these accounts, are the following : 268 On the Perturbations of Uranus. + 1 '918 sin {0! 20 2 13 1 '5} + 1 '085 sin {0 <& } 0> 0i, 02 being the mean longitudes of Jupiter, Saturn, and Uranus, respectively. In the Reduction of the Greenwich Observations, the latter correction was already taken into account. M. Hansen having also found some new inequalities in the motion of Uranus, depending on the square of the disturbing force, I re-computed the values of these, following the same method as that given by M. Delaunay in the Conn.des Temps for 1845, and my results agreed very closely with his, the terms to be added to the longitude being H O I + 32 -00 sin {302 60! + 20 + 22 18 '8} 8 *35 sin (20260! + 20 +39 10 '5} 1 '49 sin {402 60! + 20 + 34 48 '4} With respect to the inequalities of higher orders neglected by Bouvard, I considered that the most important of them would be, either those of long period, or those whose period was nearly equal to that of Uranus. During three-fourths of a revolution of the planet, the effects of the former class would be nearly confounded with those arising from a change in the epoch and mean motion, and those of the latter class with the effects produced by a constant change in the eccentricity and longitude of the Perihelion. The position of the planet to be determined would therefore be little affected by these terms, and the others would probably be much smaller than thos which would necessarily be neglected in a first approximation to the perturbations produced by the new planet. 8. Taking into account the several corrections above-mentioned, the residual differ- ences between the theoretical and observed heliocentric longitudes were the following: Ancient Observations. Modern Observations. Year. Observation Theory. Year. Observation Theory. a H 1690 +61 '2 1780 + 3 '46 1712 +927 1783 + 8*45 1715 +73-8 1786 +12*36 1750 47-6 1739 +19-02 1753 39'5 1792 +18*70 1756 45'7 1795 +21-38 1764 -34'9 1798 +20-95 1769 19*3 1801 +22-21 1771 2'3 1804 +21-16 1807 +22-07 1810 +23-16 1813 +22-00 1816 +22-88 1819 +2069 1822 +20-97 1825 +18-16 1828 +10-82 1831 3*98 1834 20-80 1837 42 -66 1840 66 '64 On the Perturbations of Uranus. 269 9. It is easily seen that the series expressing the correction of the Mean longitude in terms of the corrections applied to the elements of the orbit, is more convergent than that which gives the correction of the true longitude, and the same thing is true for the perturbations of the mean longitude, as compared with those of the true. The corrections found above were accordingly converted into corrections of mean lon- gitude by multiplying each of them by the factor -T-, r being the Rad. Vector, and a and b the semi-axes of the orbit. Hence these latter corrections were found to be the following : Ancient Observations. Modern Observations. Year. Observation Theory. Year. Observation Theory. 16 ( JO +62" '6 1780 +3 '42 1712 +81 '5 1783 + 8 -19 1715 +67'2 1786 + 11'74 1750 51-8 1789 +i7'75 1753 43'2 1792 +17-22 1756 50-1 1795 +19-52 1764 37-8 1798 +19 '06 1769 20 '5 1801 +20-21 1771 2-1 1804 +22 -19 1807 +20-52 1810 +21 '89 1813 +21'I9 1816 +22-50 1819 +20 78 1822 +21-50 1825 +18'97 1828 +11 -50 1831 4 '29 1834 22 '63 1837 46-/0 1840 73 09 These numbers form the basis of the subsequent investigations. 10. Let 5e, 5, 5e, and 3tu denote the corrections to be applied to the Tabular Elements of Uranus, then the correction of the mean longitude at any time t is e = Sf + 2e 8 3CT + t %n {2 cos (ra + f CT) + cos 2 (nt + f. }] ccrz + {2 sin (n t + t-rc) + sin 2 (w^ + t-tz) j Ze If we include the small term 2 c 2 c w in the quantity 8 <-, this correction may be put under the following form : S + t S n + cos n t I x l + sin n t $ i/ l + cos 2 n t$ x z + sin 2 n tSt/i in which expression ;e a = _ e {cos (e cr) dx^ + sin (f re) ci/^ ?/ 2 = -e {sin (e-^-cj) 3 # cos (E w) 270 On the Perturbations of Uranus. 11. Also, adopting the notation of Ponte*coulant's "Theorie Analytique," the per- turbations of mean longitude = . 2 Fi sin i (nt-n't + -t') + m'e 2 GiSin {z (nt n't + e-c') (rc <-f -rr)} + m'e 1 S H, sin { i (n t-n't + e- E ')- Where the accented letters belong to the disturbing planet, t takes all integral values, positive and negative, except zero, and if we put t (n n 1 ) = z 9 the values of F Gi and H,- are the following : 3 i n* in* 2n* 2 dA i n) da ' , 3^ 8 _) ^ 2 -7 2 + 2r(2r ) (0-2 /Of ; 2) 2z 2 n* c^^h- (3 (i-\) i (^-IX 1 (f- 1) (2 i-l)n) ti (^-w) 2 ^ (0 g) + 3 (02 > r Ai - ! 12. Now, if we assume -^7 or a = sin 30 = 0-5, the values of the fundamental db t d*b quantities 6, a -7- , a 2 --j , will be log. 6 =0-33170; log. a ^= 9 '53 765 log. a 8 ^ = 9 77848 log. ft, = 9 '74 197 ; lo:r. a ~ = 9 '83868 ; log. 8 ~ = 9 70857 log. 6, =9'32425; log. ~ = 9 '68012 log. a 2 ^;= 9 '87776 log. 6 3 = 8 '9 1670 ; log. a 3 = 9 '463 1 $ log. a 2 = 9 '86253 On the Perturbations of Uranus. 271 Hence the principal inequalities of mean longitude, produced by the action of a planet whose mass is , that of the Sun being unity, and the eccentricity of whose orbit is -- will be the following : 36-99' sin \nt-ri t + e e'} + 58 '97 m 1 sin 2 {nt n't+e e 1 } + 5 '80 m' sin 3 {nt n't + t t?} + 2 *06 m' sin [n't+e 1 &} 4 -30 wV sin {n't+e' vs 1 } + 31 '25 m' sin {nt- 2n't+e 2 e' -12-14 m'e' sin {nt-2 n't+e-2 e' + 48 '55m' sin {2 n t-3 n 1 1+2 #3 -93-01 wV sin {2 nt 3 ra'*+2 e S To these may be added the following, which are of two dimensions in terms of the eccentricities : + 0*57' sin 3 {nt-n't+ (. (.'} -1 '08 m'e'sin. {3 (nt-n 1 t+e-f 1 ) -w+w'} These expressions may be put under the following form : hi cos (nn 1 ) < + A 2 cos 2 (?i n f ) t+h a cos 3 ( n fi, f )t + ki sin (nri) t+k^ sin 2 (n n') <+A 3 sin 3 ( n n')t rit-\-q z sin (n 2^') ^ + ^38^ (2n 3n')t 13. Let the time of the mean opposition in 1810 be taken as the epoch from which t is reckoned ; this date, expressed in decimal parts of a year, will be 1810- 328. Also, let 3 synodic periods of Uranus, = 3 * 0362 years, be taken for the unit of time ; then the change of the mean anomaly in an unit of time will be 130 / '5; also w=13 0''6, ? i / =436 / '0 .-. n w'=8 24'-6, n 2ra'=3 48' '6, 2^-3^ = 12 13' '2. Hence the equations of condition given by the modern observations will be of the form II 01 01 c SE + $XI cos {13 '5} < + 3a; 2 cos {26 1 '0} t + cyi sin {13 '5} *+<5y 2 sin {26 1 '0} t 01 01 01 cos { 8 24 -6} t+ h z cos {16 49 '2} t+h 3 cos {25 13 '8} t sin { 8 24 '6} t+ k z sin {l6 49 '2} *-f 3 sin {25 13 '8} t + Pi cos { 4 36 -0} t+ p 3 cos { 3 48 -6} t+2>* cos { 12 13 '2} t + q l sin { 4 36 '0} t+ q z sin { 3 48 '6} t+q 3 sin {12 13 '2} t in which t assumes all integral values from 10 to +10 in succession, and the several values of c" are contained in the table given in Article 9. 272 On the Perturbations of Uranus. 14. The final equations for the corrections of the elliptic elements will be found by multiplying each equation successively by the co-efficients of e, Sn, $Xi and ^y,, which occur in it, and adding the several results. Let the equations be treated in a similar manner with reference to the quantities /*i> ,? h kz> ^3, & P*> P^ fr- it will be seen that, in consequence of the arrangement which has been given to the equations of condition, the equations thus formed naturally separate themselves into two groups, one of which involves only <), Sx 19 Sa? 2 , with the quantities h and p, while the other involves Sn, ty H o>y 2 > with the quantities k and q. Also, the co-efficients in these equations are easily calculated by the following for- mulae, putting t=\Q in their right hand members: sinm , 1 , 1 sin m Zco*m< ^^ + oo 22 sm 15. By performing the calculations, the equations of the first group are found to be the following : (0 15) '48= 21-0000&-+ 6 -0670 a*!- 4'4358d^ 2 + 13 '6320 h, + '4043 2 - 4 '5608 7i 3 + 18-6046^+19-3384 jt? 2 + 7-3721 p* (x) 246-48= 6'06703e+ 8 '2821 ^x,+ 4 '1762 3 a:, + 7-40417^+ 8-2523 h*+ 4*6963 h 3 + 6-5389^+ 6-3978 ^ 2 + 8-1831 p., C/O 20974= 13-6320^+ 7 -4041 a*!- 0-23375^ + 10 -7022 ^ + 4-5356 h 2 0*0018 h. d + 12*7013^ +12-9883 p z + 8 '0038 p 3 'M 242 '68= -4043 h + 8 '2523 80:,+ ^ '5650 ^, + 4-5356^+10-2960 A 2 + 8-1944 h 3 + 1-7866^+ 1-3667 jo 2 + 7-6671 p 3 (A a > 86-67=- 4*5608 a + 4-69633^+10-50235^ -00187*^ 8-1944 A,+ 10-7071 h a 3-0812;?, 3-5347 ^8+ 3 '8855 /?, On the Perturbations of Uranus. 273 # 1 -3 -4948 a# 2 + 12*9883^ + 1 '3667 7* 2 -3*5347 7* 3 -1-17 '2795 j^ + 17 -9106 jp,+ 7 "5423 p 3 212-56= 7'372lS + 8 '1831 5^ + 3 '40/1 a ar, + 8-00387*!+ 7'6671 7* 2 +3-8855 h a + 7*6127^ + 7'5423 p 2 +8*2019 p, 16. By means of (<) eliminate It from each of the other equations, and these latter become n (x-) 202 -72 6 -5294 Sa^ + 5 '4577 z 2 +3 *4658 7* t + 8 '1355 7< 2 + 6-0139 7* 3 +l-l640 ^ + 0-8109^2 + 6-0533^3 (^) 111-41= 3 *4658^ + 2 '6458 S tf a + 1 '8531 7* t + 4 '2731 h* + 2*95887i 3 +0-6243 p 1 + 0'4349/? 2 + 3-2183jr? 8 (7O 239 '76= 8 -1355^ + 7 '6504 a# 2 +4'2731 ^+10 '2882 h 2 + 8 -2822 7i 3 +l '4284 J9 t + '^944 p 2 + 7 '5252 p a (7* 3 ) 119'57= 6 -0139 &tfi + 9 '5389 a # 2 +2 '9588 h,+ 8 "2822 h* + 97166 A3+0'9593 ^ + 0-6652^+ 5 -4866/73 26'50=r 0-8109 ^^ + 0-5900 ^^+0-4349 7*,+ '9944 7* 2 + 0-6652 /* 3 +0 '1470 ^ + 0-1024^+ 0'7535p 3 189'38= 6'0533Sx! + 4 -9643 Jx 2 +3 '2183 A!+ 7 -5252 A 2 + 5-4866 ^3+1*0815 ^,+0-7535^+ 5-6139^3 1 7- Again, by means of (a;) eliminate 5 x l from each of the other equations, and we find 3 -807 = --0 '2512 to 2 +0 '0135 ^0 '0452 7* 2 '2334 h z + -0065^-J-O -0045^+0 -0052^3 (7* 2 ) 12 '821= '8502 Sx 2 0*0452 A t 4-0 -15157*2+0 -7890 A 3 '0219^0 -0160 p 2 -0171^3 (A 3 ) 67 '149= 4 -5120 &e 2 -2334 7* t + *7890 7* 2 +4 '1775 h a -1 128 ^ *0817jtv- -0888 p s 1 -327= '0878 r*+0 -0045 h, *0l60 h z '0817 7* 3 + '0024^ + 0017# s +0 -0018p 3 1 -448 = ^0 -0955 a# 2 + '0052 h^ *0l7l ^ 2 -0 '0888 h 3 + 0*0024^ + '0018^+0 -0020^3 18. Similarly, the equations of the second group are found to be O) 171 -27 = 77 -0000 *n + 9 "3938 ^ 1 '2183 a y % + 8-8463 ,+ 7-3034 k t '5927 3 + 5-7519 ^1+ 4-8755 q a + 9*5583 ^ s (y) ^166*33= 93'9380^+12*7179Syi+ I'8907ay 2 + 11-2022 ^+11*0848 k*+ 2*6731 k 3 + 7-0956 ^+5-9913 ry,+ 1 274 On the Perturbations of Uranus. _]82-87 = 88 -1630 8n + 11 "2022 S^ '3210 $ y* + 10-2978 ^+9*0964 k 2 + 0'406l k 3 + 6-6370 q,+ 5-6l63 2 +l 1-3346 q 3 89 -07 = 73 -0340 fa + 11 -0848 ?/!+ 4 '8266 Jy 3 + 9-0964 ^+107040 ^ 2 +5-4376 k., + 5-5855 q,+ 4 '6976 q z + 10 '9375 q. A +124-80= - 5-9270 J+ 2-6731 ^+10-42535^ + 0-4061 ,+ 5-4376 2+10-2929 k 3 '2497 q l '2643 # 2 + 2 '1788 ? 3 107*02= 48-7550 8n + 5'9913 J^ 0'66l4$y a + 5-6163 A!+ 4 -6976 ^ 2 0-2643 ^ 3 + 3-6475 ^+3-0894 ^+6-0897 g ? _175 -89 = 95 '5830 Sn + 12 7441 Sy,+ 1 '3845 Jy 8 + 11-3346 ^+10-9375 ^ 2 + 2'1788 ^ 3 + 7'2084 q,+ 6'0897 ^ 2 + 12 7981 q 3 19. By means of (w), eliminate S n from each of the other equations, and we have (//) 42-61= 1 '2578 fyi+ 3 -3771 &/2+0 '4100 ^ + 2 '1748 k 2 + 3 -3962 3 + '0785 ^ + '0433 # 2 + 1 '0833 q 3 (k,) 13-90= 0-4100 fy t + 1-0787 ai/ 2 + -1346 ^+07057^ 2 + 1-0871 3 + 0-0288 ^ + 0*0150 ^+0 -3534^ (A z ) 73-38= 2-1748 fy,+ 5 '9822 S# 2 +0 705? ^ + 3 7767 A 2 + 5-9998 4+ 0-1298 ^+0-0732^+1-8715^ ( 3 ) 111-62= 3-3962 3^+10-3315 tys+l -0871 ^ + 5-9998^ + 10-2473 ^ 3 + 0-1930 ^ + 0-1110 ^+2 '9145 q 3 (ry 2 ) 1 '42= -0433 fy t + '1100 y a +0 '0150 A x + '0732 k z + 0-1110 A 3 + 0-0055 ^ + 0-0023^+0-0375^3 (^ 3 ) 36 72= 1 -0833 3^+ 2 -8969 %/ 2 +0 -3534 ^+ 1 '8715 k a + 2 '9145 A 3 + -0684 ^ + -0375 ^+0 *9330 q 3 20. Again, eliminating 5^ by means of (y) we find (& -009= -0221 3y 2 +0 -0010 ^-0 -0032 ^-0 '0200 ^ 3 + -0032 ^+0 -0009 <7 2 +0 *0003 q 3 (A 2 ) -0-301 = 0-1430 fy 2 -0 '0032 ^+0-0162 2 +0-1274 3 -0 -0059 ^-0 -0017 &-0 -0016 q 3 (A 3 ) -3 -443 = 1 -2129 fya-0 '0200 ^ + '1274 k*+l '0769 &, -0 -0189 ^,-0 -0059 ?2-0 -0105 (7 3 -0 -045= -0062 fy 2 +0 -0009 ^-0 -0017 2 -0 '0059 k 3 + '0028 ?, + -0008 (7s+0 '0002 q s +o-oi7=-o-on6 ^2+0-0003 ^-0-0016^2-0-0105 k. A + -0008 ^ + -0002 ft+0 -0000 jr, On the Perturbations of Uranus. 275 21. From the equations remaining in the two groups after the elimination of $ , 5 n, & x n 2y\ it will be easy, when approximate values of the mass and mean longitude of the disturbing planet have been found, to deduce the final equations for determining these quantities more accurately by the method of minimum squares. It maybe observed, however, that the equations in each group are very neaily identical with each other, aud therefore two final equations may be formed by simply adding together the several equations of each group, after giving the unknown quan- tities the same sign in them all. Thus we find 86 '552= -5 7967 3a: 2 +0 '3018 7^-1 '0188 ^ 2 -5 '3704 h 3 + -1460^ + -1056^+0 '1149 p 3 3 725=-l '3958 fy 2 +0-0254 ^-G'1501 2 -l '2407 k 3 + '0316 ^+0 '0095 # 2 +0 '0127 q 3 22. If in the expressions before given for^x a and $y z we substitute e = '046679 and e iz~ 50 1 5' "8, we obtain &a? 2 = -007460 Sa^ + -008974 #! Sy 2 =-0-008974 Sarj + -007460 iyj Substituting these values in the equations (x) and (?/) and in those just found, it may be seen that by adding to the latter equations -006768 Cr) + -040287 (y) and '001869 (z) + '008187 (#) respectively, S x l and ?/, will be eliminated, and we shall obtain the following equations : (1) 89-641 = 0-3252 ,-0-9637 2 - 5-3297/* 3 + -0165 h +0 '0876 2 +0 '1368 k 8 + -1539^+0 -1111 j0 2 +0-1559/? 3 + '0032 q, +0 -0017 ? 2 +0 '0436 q 9 (2) 3-695=: -0-0065 A, -0-0152^-0-01I2^ 3 -f '0288 Aj '1323 ^ 2 -l '2129^ '0022^ '0015^20 -0113^3 + '0323?! +0 -0099 ? 2 +0 '02 15 q 3 23. These equations would be sufficient for determining the mass of the disturbing planet and its longitude at the epoch, if the eccentricity of the orbit were neglected. We will now proceed to find equations from the Ancient Observations for determining the eccentricity and longitude of the Perihelion. The equations of condition given by the Ancient Observations are the following : 62-6= Se- 0-8776 a^ + 0'5402 ^ + 0-87127*, + 0-5 180 2 -39-31 S/i-0-4795 c^ + 0-8415 %/ a -f 0-4909^ + -8554 2 + 0-0314 7i 3 0-9999 JV- -8640^ 2 -5Q55p a + 0-9995 >& 3 + 0-0145 #! 050352 8 --0 -8628^ '27b On the Perturbations of Uranus. 84-5=3 & + 0-4975 ^-0-5050 &TJ + -0288 Ar-0 -9984 A 2 32-30271 0-8675 c^0-8631 B*/. 2 + 09996 A! 4- 0-0573 A, 0-0860 A 3 0-8534 p l 5456^ + -8220^ 3 0-9963 V-0-5213 ft 0-8380 ft 0-5695 ft 67-2= c + -6732 San -0935 &r 2 -11207*, -9749 /* 31 -31 Jw 7394 fyi -9956 fya+0 -9937 A' t '2227 # a + 0-3305 A 3 0*8105 j9 t '4912 p 2 +0 '9206p 3 0-9438 3 0-5857 ft '8711 ft "3905 ft 51 '8= Se0-2616 Sav- 0-8631 &K a -9649 A t + '8618 A, 19 '59 Sw + -9652 fy! '5050 Sy 2 '2627 A t + *5073 A 2 '6982 ^30 '0023 J3 t + '2650 /> 2 '5090 p s 0-7159 ^ 3 l-0000 ft -9642 ft-fO '8607 ft 43 -2= Se '4741 Sx t '5505 &r 2 '9154 ^ + '6758 A 2 18-58 Sw+0'8805 5^0 '8348 fy 2 '4025 A t + '7371 k 2 0-3220 /i 3 + 0-0787 ^ + 0-3291^20-6814^3 -0 -9467 3 -9969 ft-0 -9443 ft+0 7319 ft 50-1= Sf 0-6430 &T! 0-173I ^ 2 '8543 ^,+0 '4599 h z -17 '68 Sw+0 -7659 fy; '9849 ^ 2 '5198 ^ + '88/9 ^ 8 + 0-0686 Ag+0'1510 /^ + -3848^2 '8085^3 -9976 V-0 '9885 ft -9230 ft+0 -5885 ft 37-8= Se 0-9492 S^ + 0'8021 ^ 2 0-6189 A! 0-2340 7i 2 15-25 S7Z+0-3145 ^ t '5972 5y g *7855 A t + '9722 ^ + 0-9085 7i 3 +0-3396 j^+0 '5287^0 '9939 ;? 3 0-4179 A 3 -9406 ft -8488 ft+0 -1100 ft 20 -5= h '9985 ^ + '9942 5^20 -4128 h l '6591 // 13-60 2w 0-0538 ^, + 0-1074 57/20-9108^ + 0-7520^ + 0-9571 ^ 3 + -4607 ^ + 0-6182^20-9711^3 + 0-2899 ^ 3 0-8875 ft -7860 ft '2385 ft 2 -4= & "9633 S^ + -8560 Sx, -2807 ^0 '8424 h a 12-64 tin '2684 5^ + '51/0 cy 2 '9598 ^ + '5388 k t + -7536 7/3+0 -52/9 jt? t + '6670^0 '9023^8 + '6574 7^ 3 -8493 ft 7451 ft '4310 ft 21. From each of these equations eliminate e, 8n t Sx it and Sy l9 by means of the equations (*), (/z), (a?), and (?/) before found, and we have the following : -14-2-0= 1-/265 fce 2 +0 -84127/i+l '9521 7? 2 + 1*3230 A, 1 1 -3691 J?/2+3 -6001 ,2 -8793 #2 10 -9578 & 3 1 -6779^1 -6400 jt? 2 + -2249^8 + 2 -6815 ft+ 1 '8369 ft+ -2995 ft On the Perturbations of Uranus. 2/7 105%= 0-4681 2av-073ii hi i -2776;*, 0-06097*, 9-6249 Sy 2 + 3 7087 7^2-1926 V- 9 '5426 3 --1 -7765^ 1 '4924 p z + + 1 -6997 ?i + l '1014 8 , q 3 ; it will be proper, therefore, to combine the above equations in such a manner that these quantities may acquire the largest co-efficients possible. This will be done by multiplying each equation by a quantity nearly proportional to the co-efficient of each of the unknown quantities p 3 and q 3 , and adding together the several results. It was thought unsafe to employ the first of the above equations, since it is derived from the single observation of Flamsteed, made in 1690, twenty-two years anterior to any other observation. 278 On the Perturbations of Uranus. Hence the equation for finding p 3 may be formed by multiplying the above equations, taken in order, by -0'8, '6, +1 -0, +1 '0, +0 '9, +0 '6, +0 '4, +0 '3 beginning with the second ; and the equation for q* by multiplying the same equations by I'O, 1 -0, 0'5, 04, 0-3, 0-2, 0*1, '1, Hence we obtain 474"-! = 4 -114&c 2 2 '8 17 /*!+ 7 '837 h t + 4 *528 h s -20 745 fy a 2 789 7^-6 '551 * 2 20 '666 k, + 0-193^ + 0-377^ 1-489^3 1 -660^ 1 -078^ 0'054 ? 3 485 -0 = '446 az 2 3 '308 h, '442 h z + I '629 h s 32 -961 cy 2 + 8 *267 k, 8 *805 2 32 '546 3 4-473^3 -643/? 8 + 0'037^3 2-278^+ 2-086^ 26. Eliminate cx z and Sy 2 from these equations by means of (cc) and (y) and they become ( 3 ) _ 476"-7 = 2 '930 A t + 7 -572 A, + 4 '332 k a 2 751 k, 6 -348 2 20 '350 7< 3 1 -653 and -A- are m' a ^=48*' '55 sin (3 y6) 93 '01 e' sin (3 ') ^ = 48 '55 cos (3 ,6) 93 '01 e' cos (3 ft') where e &' = fi. Equating these to the values given above, we find e' = 3 '2206, ft' =262 28', and /. ro' = 315 27'. Hence long, of Perihelion in 1846 = 315 5?'. Lastly, substituting the values just obtained in equation (1), we find m'= "82816. 31. Hence the values of the mass and elements of the orbit of the disturbing planet, resulting from the first hypothesis as to the mean distance, are the following : !=;' Mean Long, of the planet, October 6, 1846, 325 7 Longitude of the Perihelion 31557 Eccentricity of the Orbit - - - - - -O'l6l03 Mass (that of the SUN being 1) - - - - '0001656 These are the results which I communicated to the Astronomer Royal in October, 1845. I 32. I next entered upon a similar investigation, founded on the assumption that the mean distance was about T Vth part less than before, so that , or = sin 3 1 = '5 1 5. The method employed was, in principle, exactly the same as that given before ; but the numerical calculations were somewhat shortened by a few alterations in the process, which had been suggested by my previous solution, On the Perturbations of Uranus. 281 33. Assuming then that = sin 31, the values of the quantities ft, ^~, **~d will be log. l> = '33385 ; log. ^ = 9 '57333 ; log. 2 ^ = 9 '8291 1 log. b, = 9 -76106; log. 27 = 9 '86149; log. 2 ^~ = 9 '76573 log. b, = 9 '35361 ; log. a ^ = 9 71359 ; log. of^f = 9 '92466 log. b, = 8 '98918 ; log. * g-jp = 9 -50854; log. 2 = 9 '91563 Hence, by means of the formulae given before, the principal inequalities of the mean longitude of URANUS, produced by the action of a planet whose mass is that of the SUN being unity, and the eccentricity of whose orbit is ^-, may be found to be the following : n 42 *33 m 1 sin (ntn't+t '} + 76 -55 m' sin 2 {nt n't + e e'} + 7 -25 m' sin 3 {ntn't +EE'} + 2 -34 m 1 sin {n't+e 1 vs } 4 -74 m'e'siu {n't+e. 1 w'} + 41 '72m 7 sin {nt 2n't+e 2e'+} 16 '47 w'e'sin {nt 2n't+e 2e'+cj'} + 33 -93 m' sin {2nt 3n't+2e 3e' 63 -41 mVsin {2w< 3^+2e To these we may add the following, which are of two dimensions in terms of the eccentricities : u + 0'40m ; sin 3 {nt n't+e e?} 74 m' J sin {3 (^ n't+e c') CT+OT'} 34. Now, on our present assumption, ra = 13 0' *6, w'= 4 48' *5, n n f ~8 12' *1, w-2w'=3 23' -6, 2rc~3ra'=ll 35' 7. Hence the equations of condition given by the modern observations will be of the form II O / O / c= h +5^008 {13 0'5}*+S# 2 cos{26 1 '0} t +$# 1 sin {13 0-5}*+fy a sin {26 1 '0} t p + ^ cos{ 8 12'1}<+ ^ 2 cos {16 24 -2}*+ a cos{24 36'3}j! + * sin { 8 12 -1} t+ k t sin {16 24 '3} t+k a sin {24 36 '3}* + p l cos { 4 48 '5} t+ p* cos { 3 23 '6} t+p s cos {11 35 7} t + ^sin { 4 48 '5}^+ & sin { 3 23*6}< + ^ 3 sin {11 357}< u 2 282 On the Perturbations of Uranus. 35. Treating these equations of condition in the same manner as before, the equa tions in the first group, derived from them, are found to be the following : (e) 151'48= 21*00003e + 6 *0670 3^ 4 '4358 3x 2 + 13 '9515 A! + 0-9471 h 2 4 '5965 h* + 18-3916^+19-6752 p*+ 8'4184 p s (x) 246*48= 6'06703e+ 8 '2821 3^ + 4*l7623x 2 + 7 '3540 7^ + 8-3027 h 2 + 5'096l 7i a + 6-5793^ + 6-3319 jt? 2 + 8 -0850 p a (A,) 207-58= 13 '9515 3e + 7 -3540 3^ *4177 3a? s + 10-97357^ + 4'6775 7*2 0-0005 h a + 12-8697^+13*4050 jt? 2 + 8-4781 p a (7* 2 ) 245-17= 0*94713 + 8-3027 ^ t + 7*23625^ + 4 -6775 A!+ 10 -0259 7* 2 + 8 '3220 7/ 8 + 2-3661^+ 1'6727 p*+ 7*3073^3 (7i) 103 -48= 4 -5965 3e+ 5 '0961 ^+10 '5558^ - -0005 ^+ 8 -3220 7/ a + 10 '9749 h a v 3-7316 p z + 3-5852 p a 36. Similarly the equations in the second group, are (n) 171 -27= 77 '0000 ra+ 9 '3938 3^ 1 '2183 Sy 2 + 87355 k,+ 7-6213 k z O-OSQO A, + 5-9764 ?!+ 4-3875 ^ 2 + 9-6152 ^ (y) -166-33= 93*93803^+12-7179^+ 1-8907^ + 11-0393 ^+11*3717 ^ 2 + 3-3196 k a + 7*3747 ?!+ 5.-3S25 ^+12-6816 ^ 3 (*) 181 -31= 87 -3550 3w + ll *0393 c^ '3758 3# 2 + 10-0264 ^+ 9'2740 7^ 2 + 0-9476 k a + 6*8054 ^+ 4*9866 # 2 +ll-1971 q a 99*51= 76-2130 Src+11 -3717 3^+ 4-4810^ 2 + 9*2740 #!+ 10 -9740 2 + 5'6294 k a + 6-0523 # t + 4-3916 #2+11-0843 # 8 113*14 = 0*5900 $n+ 3-31963^+10*21123^ + 0*9476 k,+ 5*6294 ^+10*0251 ^ + 0-1746 ? t + 0-0454 # 2 + 2*4791 # 3 37. The equations (p 2 ), (j^s) of the first group, and (# 2 )> (#3) of the second were not formed, as our previous solution shewed that when Se, SM, Jaf 1? and Jy n were eliminated, the co-efficients of the remaining unknown quantities in these equations would be extremely small. It will be preferable to combine the equations (Ai), (A 2 ), (^ 3 ), and (*i)> (^z)j (^3) before, instead of after, the elimination of &, 8n, $x lt and &/!, from them. On the Perturbations of Uranus. 283 If then we change the sign of the third equation in each group, and add it to the fourth and fifth, we obtain 141 -07= 17 '6009 $ + 6 '0448 S^+18 '2097 &e 2 6'2965 7^4-13-6704 7< 2 +19-2974 h. A 13 '3971 ;?, 15-4639 p*+ 2-4144 p s 194 '94= 11 '7320 Zn+ 3-6520 ?/,+ 15 '0680 ty 8 + 0-1951 k,+ 7'3294 &+ 14 -7069 3 '5785 q, '5496 q z + 2 '3663 q 3 38. By means of (t) and (n) of Articles 35 and 36, eliminate oe and bi from (x) and (?/), and also from I he equations just found, and we have a (x) 202 72= 6'5294 a^+ 5-4577 fog + 3'3234 h+ 8 '0291 7* 2 + 6-4240 A 3 + 1-2659 ^ + 0-6477^2+ 5-6529^3 42'6l= 1-2578 3y t -f- 3 '3771 ^+0*3822^+ 2*0739^ + 3-3916 k B + 0*0836 = 76"'55 sin 26 -i-, = -42 *33 cos e, 2 , = 76 '55 cos 2 771 */* ^ = 7%5 sin 30+0 -007460 ' + '008974 f m Tfi wi ^= 7'25 cos 30-0 '008974 0+ 0-007460^ )= -20 sin (0-^8)- -074738 \^j cos 20 -- ^ sin 2 0} Wt (.'W Wi J -}=- 0-20 cos (0-y6) + -074738 |^5 sin 20 + ^cos 20} g= 32 '91 sin (20-^) + -259765 jocose -^ sin 0} ^J= 32-91 cos (2 0-y8) + -259765 {^ sin +|/ cos0} 46. Substituting these expressions in the above equations, and putting for ft its value 50 1 5' '8, we obtain 0= (1 -24872) sin0 + (l '32231) cos0 (1 '48110) sin 20 + (2 '24265) cos 2 (1 '48373) sin 30+ (2 '22809) cos 3 0+(9 '26254) ~,-(.9 '50079) J? + (8'44376) |> cos Jv sin 01- (8 ' -(8-17031) j|? cos 20- !' sin 20}-(8 '0686l) {7 sin 20 + ^ cos 2 0} On the Perturbations of Uranus. 287 0= (I -65190) sin 0+ (2 -06584) cos + (2 "30220) sin 20-(2'60306) cos 20 -(2 -19916) sin 30- (2 -15032) cos 3 (0 *14305) / (9 '60933) + (9 '34981) { cos 0- $ sin0}-(9 '31615) {**+ cos 0} -(8 -85046) j^> cos 2 0-? sin 2 0}-(9 '11828) j|, sin 2 + $ cos 2 0} 0= (1 -91407) sin 0- (2 -55189) cos 0- (2 '62790) sin 20- (2 '64230) cos 2 (2*25331) sin30-(2-34185) cos 3 + (9 '96344) ?+ (0 '56029) $ -(9-83835) {^cos0-$sin0} + (9'64968) ||? sin0 + J*cos 0} + (9 -45371) |: cos 20-$ sin 20j + (9 '47306) {^ .in 20 + $ cos 2 0} where the numbers enclosed within parentheses denote the logarithms of the corres- ponding co-efficients, as before. 47. From these equations, we find, by the same method as before = -4655', ^=:138"'92, $=-109'83 Hence, since e = 217 55', e' = 264 50', the mean longitude of the disturbing planet at the epoch 18 10 '328. The sidereal motion in 36 synodic periods of URANUS = 57 42', Precession = 30'. .*. Mean Longitude at the time 1846 '762, or October 6, 1846, = 323 2 ; . Also, the expressions for --/ and - "J are > = 33 '93 sin (3 /8)-63 '41 e' sin (3 0-;6') $ = 33 '93 cos (3 0^-63 '41 e' cos (3 0-0') wnere ro'rr ft. Equating these to the values given above, we find e' =2 '4123, /6' = 279 1 1', and .' . CT' = 298 41'. Hence longitude of the perihelion in 1846 = 299 1 1'. Lastly, substituting the values just obtained in equation (1) of Article 39, we find w*'=0 -75017. 48. Hence the values of the mass and elements of the orbit of the disturbing planet, resulting from the second hypothesis as to the mean distance, are the following: Mean Longitude of the Planet,0ctober 6, 1846, 323 2 Longitude of the Perihelion ...... 29911 Eccentricity of the Orbit ....... '120615 Mass (that of the SUN being 1) .... '00015003 288 On the Perturbations of Uranus. 49. From the values of m', 0, ~/and -^ found above, the values of the quantities h t k, p, and q, corresponding to each hypothesis, are immediately determined. Thus we find 1st Hypothesis. 2nd Hypothesis. =0-5 = 0-515 A t = 23-98 A l= = 19-07 A t == 23'19 ^= 21-69 A 2 = 47 '58 A 2 = 11 *00 A 2 = 57 '30 k z = 3 '83 A 3 = - 1-93 A 3 = 7 -64 A 3 = 3 -40 k 3 = 5 76 Pl = 9-93 ^1 = - 8-31 ^= 6'52 gi= 7*34 p a 8-54 ^ 2 = 55 '36 ^ 2 = 11 '62 ft =r 54 '39 p 3 = 224-90 5-3= 171-63 j9 3 = 104-21 ^ 3 = 82-39 50. And by substituting these values in the equations (), (w), (z), and (y), we obtain 1st Hypothesis. 2nd Hypothesis. a ~rf = 0'5 a 0-515 IT f 1 49-77 2 = o 702 B = 43 -23 ^w = 0-5417 ^=130-69 c Jy l= = 222 '38 ^= 1 77 $y l= = 123 '98 ; 2 = 1 -02 I ?t/ 2 = 2 -83 ^X 2 = 1 *13 gy 8 = -91 and the corresponding corrections of the elliptic elements will be -=0 '00000999 = ' 0000 77 l It will be seen that the corrections of the eccentricity and longitude of perihelion vary very rapidly with a change in the assumed mean distance. 5 1 . If these quantitities be substituted in the expressions before given, we obtain the following theoretical corrections of the mean longitude, each of these corrections being divided into two parts, of which the first is due to the changes in the elements of the orbit of Uranus, and the second to the action of the disturbing planet. On the Perturbations of Uranus. 289 HYPOTHESIS I. Ancient Observations. Modern Observations. Year. 1712 288 '0 + 365 '8= +77 8 Year. 1780 a it 126-12+129 27=+ 3-15 1715 283 1 + 357 *l = + 74 o 1783 180 28 + 188 70=+ 8 42 1750 + 210 5260 7= 50 2 1786 227 66 + 240 36= + 12 70 1753 + 218 1267 0= 48 9 1789 265 70 + 281 63= + 15 9 3 1756 + 214 0260 0= 46 '0 1792 292 25 + 310 38= + 18 13 1764 + 154 0186 7= 32 7 1795 305 84 + 325 27= + 19 43 1769 + 79 6100 7= 21 i 1798 305 67 + 325 72= + 20 05 1771 + 27 6 41 8= 14 2 1801 291 77 + 312 05 = + 20 28 1804 264 '95 + 285 38= + 20 43 1807 226 78 + 247 51 = + 20 73 1810 -179 43 + 200 76=+21 33 1813 125 59 + 147 72= +22 13 1816 - 68 21+ 91 02= + 22 81 1819 10 40+ 33 18ac+22 78 1822 + 44 84 23 '64 = + 21 20 1825 + 94 69- 77 64= + 17 05 1828 + 136 73-127 48=+ 9 25 1831 + 168 94172 17=- 3 23 1834 + 189 85211 04= 21 19 1837 + 198 51243 59= 45 08 1840 + 194 54269 36= 74 82 HYPOTHESIS II. Ancient Observations* Modern Observations. Year. a n H Year. H 1 ,,. 1712 133 7+211 9= + 78 2 1780 133 10 + 135 98=+ 2 88 1/15 -117 7 + 191 5= + 73 8 1783 149 47+157 87=+ 8 40 1750 + 85 2134 4=-49 2 1786 160 15 + 172 99= + 12 84 1753 + 73 8122 2 48 4 1789 -164 52+180 64 = + i6 12 1756 + 59 1 105 2= 46 1 1792 162 30+180 58 = + 18 28 1764 + 2 7 36 4 = 33 7 1795 153 59+173 07= + 19 48 1769 43 1+ 20 8 = 22 3 1798 138 87 + 158 86= + 19 99 1771 - 6 9 '9+ 54 7=-15 2 1801 118 95 + 139 08 = + 20 13 1804 - 94 '96+115 21 = + 20 25 1807 - 68 25+ 88 85 = + 20 60 1810 40 33+ 61 *6 1 = + 2 1 28 1813 12 72+ 34 91 = + 22 19 1816 + 13 08+ 9 '88= + 22 96 1819 + 35 71 12 74= + 22 97 1822 + 54 04 32 68= + 21 36 1825 + 67 18- 50 08 = + 17 10 1828 + 74 52 65 37=+ 9 15 1831 + 75 74- 79 21 = 3 47 1834 + 70 85 92 31= 21 46 1837 + 60 08105 25 = 45 'I? 1840 + 43 98-118 38 = 74 '40 290 On the Perturbations of Uranus. 52. Comparing these with the corrections of mean longitude derived from observa- tion, we find the remaining differences to be the following : Ancient Observations. Modern Observations. Observation-Theory. Observation Theory. Year. Hypoth. I. Hypoth. II. Year. Hypoth. I. Hypoth. II 1712 467 4 6-3 1780 40" '27 40" '54 1715 - 6 '8 6'6 1783 0'23 0-21 1750 1-6 2-6 1786 0-96 l-io 1753 457 +5'2 1789 41'82 41-63 1756 4-1 4-0 1792 0-91 1'06 l/6l 5-1 4-1 1795 40-09 40'04 1769 40-6 41-8 1798 0'99 0-93 1771 411*8 412-8 1801 0-04 40-11 1804 41 76 41 -94 1807 0'2i 0-08 1810 40-56 40-61 1813 -94 1 '00 18J6 0-31 0-46 1819 2-00 2-19 1822 40*30 40-14 1825 41 -92 41 '87 1828 42-25 42'35 1831 1 '06 '82 1834 1-44 1-17 1837 1-62 1-53 1840 4173 41-31 The largest difference in the above table, viz. 9 that for 1771> is deduced from a single observation ; whereas the difference immediately preceding it, which is deduced from the mean of several, is very small. 53. The results of the two theories agree very closely with each other, and with observation, till we come to the later years of the series ; and it is to be observed that the difference between the theories becomes sensible at precisely the point where they both show symptoms of diverging from the observations, the errors of the second hypothesis, however, being less than those of the other. Recent observations show that the errors of the theory soon become very sensible, though decidedly less for the second hypothesis than for the first. The following are the differences of mean longitude as deduced from theory and observation, for the oppositions of 1843, 1844, and 1845 : Observation Theory. Year. Hypoth. I. Hypoth. II. 1843 4 7" '11 4- 5*77 1844 4 8 79 4- 7'05 1845 412-40 410 '18 Oil the Perturbations of Uranus. 291 For the observations of the last two years, I am indebted to the kindness of the Astronomer Royal. The three years nearly agree in showing that the errors of the first hypothesis are to those of the second in the ratio of 5 to 4, from which I inferred, in a letter to the Astronomer Royal, dated September 2, 1846, that the assumption of o, , = sin 35 = *574, would probably satisfy all the observations very nearly. 54. The results which I have deduced from Professor Challis's observations of the planet, strongly confirm the inference that the mean distance should be considerably diminished. It is of course impossible to determine precisely, without actual calcu- lation, the alteration in longitude which would be produced by such a diminution in the distance. By comparing the values of 9 given by the two hypotheses, it may be seen, however, that if we took successively smaller and smaller values for the mean distance, the values found for the mean longitude in 1810 would probably go on diminishing, while at the same time the mean motion from 1810 to 1846 would rapidly increase, so that the corresponding values of the mean longitude at the present time would probably soon arrive at a minimum, and afterwards begin again to in- crease. This I believe to be the reason why the longitude found on the supposition of too large a value for the mean distance agrees so nearly with observation. In consequence of not making sufficient allowance for the increase in the mean motion, I hastily inferred, in my letter to the Astronomer Royal mentioned above, that the effect of a diminution in the mean distance would be to diminish the mean longitude, 55. I have already mentioned that I thought it unsafe to employ Flamsteed's obser- vation of 1690 in forming the equations of condition, as the interval between it and all the others is so large. The difference between it and the theory appears to be very considerable, and greater for the second hypothesis than for the first, the errors being 4-44"*5 and +50' 7 '0 respectively. These errors would probably be increased by diminishing the mean distance. It would be desirable that Flamsteed's manuscripts should be examined with reference to this point. 56. The corrections of the Tabular Radius Vector of Uranus may be easily deduced from those of the mean longitude by means of the following formula: Ll_ L^Ts r _JL lL*y l ^_ 1 ede _? i * m f + m'e S Di cos {* (nt n't+e ')~ ^t + mV2 E; cos {i (nt ra'<+ e t') nt where & denotes the whole correction of the mean longitude at the, time t t 1 dr 3 e 3 - -j- = e sin \nt-\-e. cr}+ sin 2 [nt-\-e. cr} nearly, On the Perturbations of Uranus. f assuming all integral values positive and negative not including zero. 57. By substituting in this formula the values of m', %a, Se, &c., already obtained, and putting a = 19 '191, we find the following results corresponding to the two assumed values of the mean distance. HYPOTHESIS I. a a dr + 0'000069 cos {nt n't+e e'} + '000259 cos 2 {nt n't+e E'} + '000109 cos 3 {nt n't + e e f } + '000016 cos {n't + e' ro} -000168 cos {nt 2n't+e 2e'+cr} + '000078 cos {ntZn'f + EZe'+n'} '000049 cos {2nt3n't + 2e3e'+ia} + '000209 cos {2nt Zn't+Ze HYPOTHESIS II. a dr + '000073 cos {nt n't+e e'} + -000266 cos 2 {nt n't + e e'} + -000115 cos 3 {nt?i't + /} + '000016 cos {rit+E'rz} 0-000188 cos {nt 2n't + e + -000068 cos {nt 2n't + 2e '000053 cos {2nt 3n't+2e + -000165 cos {2nt3n't+2e3e f 58. The values of 3 and - for several late years, are the following HYPOTHESIS I. Year. 1834 ^s ii 21-19 dt ii 20 -93 1840 1846 74-82 148 -65 32-34 -39 '94 HYPOTHESIS II. // ii 1834 21 -46 20 -85 1840 74 -40 31 '62 1846 145 -91 38 -30 On the Perturbations of Uranus. 293 Hence, by means of the above formulae, we find the corrections of the tabular radius vector, to be Year. 1834 1840 1846 59. By far the most important part of these corrections arises from the term 2 T ~di } an( ^ ma y tnere f re ke immediately deduced from a comparison of the ob- Hypothesis I. + -00505 +o -00722 + '00868 Hypothesis II, +o -00492 +o -00696 + -00825 served angular motion of Uranus with that given by the Tables. In fact, the cor- rections given by this term alone for the epochs above-mentioned, are Year. Hypothesis I. Hypothesis II. 1834 +0'00447 +0-00445 1840 +0-00694 +0-00678 1846 +0-00853 +0*00818 which, as we see, differ very little from the complete values just found. The correc- tion for 1834, very nearly agrees with that which Mr. Airy has deduced from obser- vation in the Astronomische Nachrichten. The corrections for subsequent years are rather larger than those given by the Greenwich Observations, the results of the second hypothesis being, as in the case of the longitude, nearer the truth than those of the first. 60. I made some attempts, by discussing the observations of latitude, to find ap- proximate values of the longitude of the node and inclination of the orbit of the dis- turbing planet, but the results were not satisfactory. The perturbations of the latitude are in fact exceedingly small, and during the comparatively short period of three- fourths of a revolution, are nearly confounded with the effects of a constant alteration in the inclination and the position of the node of URANUS, so that very small errors in the observations may entirely vitiate the result. 61. The perturbations of Saturn produced by the new planet, though small, will still be sensible, and it would be interesting to inquire whether, if they were taken into account, the values of the masses of Jupiter and Uranus found from their action on Saturn would be more consistent with those determined by other means, than they appear to be at present. The reduction of the Greenwich Planetary Observations renders such an inquiry comparatively easy, and it is to be hoped that English astro- nomers will not be the last to avail themselves of the treasures of observation thus laid open to the world. St. John's College, Cambridge, November 12, 1846. 295 ON THE CORRECTION OF A LONGITUDE DETERMINED APPROXIMATELY BY THE OBSERVATION OF A LUNAR DISTANCE. BY THE REV. J. CHALLIS, M.A., F.R.S., F.R.A.S. PLUMIAN PROFESSOR OF ASTRONOMY IN THE UNIVERSITY OF CAMBRIDGE. IN the usual method of determining the Longitude by the observation of a Lunar Distance, the measurement of the arc between the Moon and the Sun or Star, is accompanied by observations of the altitudes of the extreme points of the arc. These auxiliary observations enable the observer to reduce the measured distance to the dis- tance as seen from the Earth's centre ; whence, by means of results of theoretical calcula- tion furnished by the NAUTICAL ALMANAC, the Greenwich Mean Solar Time of obser- vation, and, by consequence, the Longitude of the place of observation, may be inferred. The peculiar advantage of the method is, that it does not require the Longitude to be previously known even approximately. It is not, however, capable of a great degree of accuracy. The sources of error are, first, the error of observation of the Lunar Distance, and, to some amount, the errors of the observed altitudes ; next, the errors in those data of the observer's calculation which relate to the locality where the observation was taken ; and lastly, the errors of the results of theoretical calcula- tion in the NAUTICAL ALMANAC. The initial determination of the Longitude by a Lunar Distance is, therefore, to be regarded only as a first approximation, which maybe subsequently employed either in deducing from the same observations a more correct value, or as auxiliary to more accurate methods, such as the observation of an occultation of a Fixed Star or Planet by the Moon, or of the beginning or end of a Solar Eclipse, the calculating of which requires an approximate knowledge of the Longitude. In order to deduce the Longitude from a Lunar Distance with as much accuracy as the kind of observation will admit of, it is necessary to go through a calculation supplementary to that which conducted to the first approximation. An obvious method of conducting this calculation is, first, to use the observed altitudes merely for clearing the Lunar Distance of refraction, for which purpose they will in general be sufficiently accurate ; and then to compute the apparent Lunar Distance for the place of observation and the approximately known Greenwich Mean Time, in such manner as to take account of small unknown corrections which the data of the computation may require, including among them the correction of the assumed Longitude. An expression will thus be obtained for the true apparent Lunar Distance, which, being equated to the observed Lunar Distance corrected for refrac- tion, furnishes a provisional equation of condition between the unknown corrections, by means of which the correction of the assumed Longitude is determined, when by any independent means the values of the other corrections have been ascertained. x2 296 On the Correction of a Longitude determined If an occultation of a Fixed Star or a Planet by the Moon, or the beginning or end of a Solar Eclipse, happen to be observed at a place whose Longitude has been approximately found by a Lunar Distance, this first determination gives the means of calculating the Occultation or the Eclipse, and thus obtaining a correction of the approximate Longitude. The calculation maybe made precisely in the same manner as the above mentioned supplementary calculation of a Lunar Distance, the only difference being that it admits of some simplification in consequence of the small distance of the Star, or the Sun, from the Moon's centre. An equation of condition between the unknown corrections is obtained as in that case, possessing greater value than the equation of condition for the Lunar Distance, on account of the greater degree of accuracy which the observation of the Occultation or Eclipse is capable of. The main object of this communication is to point out an exact and expeditious method of obtaining the provisional equation just spoken of. The corrections of all the assumed data will be taken account of (which, as far as I am aware, has not hitherto been done), and formulae convenient for this purpose, not requiring long or complicated calculation, will be investigated. An example will be added for the sake of illustration. Let it be supposed that the Moon's Geocentric Right Ascension (R'), Geocentric North Polar Distance (X'), Equatorial Horizontal Parallax (P'), and Geocentric Semidiameter (S')> at the assumed Greenwich Mean Time, have been obtained by interpolating to second differences from the NAUTICAL ALMANAC. Let there be known by observation, the Right Ascension of the zenith, or sidereal time of observation, at the place () ; and the Lunar Distance (A), that is, the arc between the Moon's Limb and the Limb of the Sun or a Planet, or between the Moon's Limb and a Star, which arc is supposed to be cleared of refraction. Also let I = the assumed Geocentric Co-latitude, that is, the Astronomical Co- latitude increased by the angle of the vertex. 6' = R' Z, = the Geocentric Hour Angle of the Moon's centre, supposed to be East. P = the Horizontal Parallax at the place. In the annexed figures, A, C, m, are respectively the positions in space of the place of the observer, the Earth's centre, and the Moon's centre, at the time of observation. P is the North Pole of the heavens, Z and M' are the intersections on the celestial sphere of the prolonga- tions of C A and C m, and M on the arc Z M' produced is the intersec- tion of the sphere by a line through C parallel to A m. by the Observation of a Lunar Distance. 297 Let A C = />, the Earth's Equatorial radius being unity, and let C m = r. Then we have, r sin P' = 1 r sin P = p Hence, sin P = p sin P' (1) Also if the angle z A m = z, and the angle A m C = p, the plane triangle m A C gives, sin p p sin z ~ r Hence sin p = sin P sin z (2) By the spherical triangle P M M', sin P MM' sin M M' sin P M' And by the spherical triangle P Z M, sin ZM sin P Z "sinZPM = sin P MM' Hence, by multiplying together the corresponding sides of the two equations, sinZMsinMPM' _ sin P Z sin MM' sin ZP M = JnPM"' Now thearc ZM - z, MM' = p, PM' = X', PZ = /, the angle, Z P M' = 0', and if = the apparent hour angle Z P M, the angle M P M' = 0'. Substituting these symbols in the above equation, we have sin z sin (00') sin / sin p sin ~~ sin X' Hence, by substituting for sin p from (2), sin P sin / . sin (00') = g^~x/~ sm e (3) Let G = sin P sin / cosec X' (4) Then sin (0-0') = G sin = G sin (0-0'+ 0') Consequently, tan (00') = ^ _ Q. cos Q' ( 5 ) The formulae (4) and (5) serve for calculating 00', and, by consequence, the apparent hour angle 0. The calculation by the latter formula is facilitated by the use of a Table of Subtraction-Logarithms. Formulae for calculating the Moon's apparent North Polar Distance may be investigated as follows. Let X = P M, the Moon's apparent North Polar Distance, and z' = Z M', the Moon's Geocentric Zenith Distance. Then by the spherical triangle Z P M', cos X' = cos z' cos / -f sin z' sin / cos P Z M'. 298 On the Correction of a Longitude determined And by the spherical triangle Z P M, cos X = cos z cos / -f- sin z sin / cos P Z M. Hence, dividing these equations respectively, by sin z' and sin 2, and subtracting the latter from the former, cos X' cos X cos /sin (z z'} sin z sin z' cos / sin p sin z sin z' Substituting now for sin p from (2) and multiplying by sin z f , cos X' cos X -^-^ = sin P cos / sin z' sin X' But and sin0' - sinPZM' sin z sin X sin == sin P Z M sin z' sin 6' sin X' Consequently, . -- = . z . r- J ' sin 2 sin 6 sin X Hence, by substituting in the foregoing equation, cos X' cot X sin X' sin 0' cosec = sin P cos /. This equation gives for determining X, cot X = (cot X' sin P cos I cosec X') sin cosec 0' ..... (7) To adapt this expression to logarithmic computation, let tan = sin P cos / cosec X' so that ^ is a small angle, positive or negative according as / is less or greater than 90, that is, according as the place of observation is North or South of the Equator. Thus cos (X' +0) sin cotX= cos * sin V sine' .............. (9) The formulae (8) and (9) are applicable for calculating X, at whatever position on the earth's surface the observation is made. If S be the Moon's apparent Semidiameter, we have (by the figure), S Cm sin z Henceb y( 6) ; S = S'. r .......... (10) This equation serves for calculating the Moon's apparent Semidiameter, and X having been previously found. by tlte Observation of a Lunar Distance. 299 The Moon's apparent Right Ascension (R) is equal to + 0, the hour angle being supposed to be East. Let the apparent North Polar Distance of the Sun, or Planet, or Star, be 7, and the difference between its apparent Right Ascension and that of the Moon be ij. Then the apparent distance (c) of the Moon's centre from the centre of the Sun or Planet, or from the Star, is given by the equation, cos c = cos X cos 7 + si* 1 ^ sin 7 cos t] -- (11) In the case of an Occultation or Solar Eclipse it will be advisable to make use of a modification of this formula on account of the small value of c. Since cos c = 1 2 sin 2 and cos t\ = 1 2 sin 2 ^ it will be seen that 1 2 sin 2 - = cos ( X 7) 2 sin X sin 7 sin 2 ^ = 1-2 sin 2 ^-ZJ - 2 sin X sin 7 sin 8 3 Hence, sin 2 = sin 2 ~2 4. sin X sin 7 sin 2 5 If therefore d = the difference between X and 7, and if c, d, and rj, be each expressed in seconds of space, by substituting the small arcs for their sines, we have c 8 = d* + sin X sin 7 if , / sin X sin 7 ii 8 \ Hence c = d (l + ^J 1 J * (12) which formula is convenient for calculation if a Table of Addition-Logarithms be at hand. Otherwise a subsidiary angle \ mav be used such that tan x = -j * / sin X sin 7 Then, c = d sec x Now let * be the Tabular apparent Semidiameter of the Sun or Planet, and sup- pose that the distance between the nearest limbs was measured. Then the computed value of the Lunar Distance is c - S - s Let the true value be, Then, assuming the observation to be correct, we have the final equation, Or, if c be the excess of the observed above the computed Lunar Distance, the equation of condition is, $c-$S-S* = .............. (13) 300 On the Correction of a Longitude determined In the observation of an Occupation, or of the beginning or end of a Solar Eclipse, A = 0, and refraction has no effect. Hence for these cases the equation of condition is, The variations <> S and s are the corrections to be added to the values of the apparent Semidiameters of the Moon and of the Sun or Planet adopted from the NAUTICAL ALMANAC, in order to reduce them to the true values. The amounts of these corrections for given distances from the Earth's centre, I shall suppose to be known by repeated and exact measurements. The remainder of this investigation will be mainly employed in obtaining an expression for the correction a c, in terms of small corrections of the elements of the calculation which conducted to the value of c. For this purpose it will be necessary to obtain expressions for the correction (S 0) of the Moon's apparent Hour Angle and the correction ( X) of the Moon's apparent North Polar Distance. Resuming the equation (3), viz. /n n/\ sin P sin / . sin (0 ) = sm sin X' it will be seen that is a function of 0', X', I and P. Hence to the first order of small quantities, *._ ^*0^_i ^ ^ . dQ ,. d .. where S 0', SX', $ /, and & P, are respectively the corrections of the assumed values of 0', X', /, and P ; and their multipliers are the partial differential coefficients of with respect to the same quantities. For obtaining these partial differential coefficients it will be convenient to use, instead of equation (3), its logarithmic equation, viz. Log sin (0 0') = Log sin Log sin X' + Log sin I -f Log sin P Hence, differentiating with respect to 0', = cot (0 - 0') sin cos (0 - 0') dO' cot (0 - 0') - cot ~ sin0' ( , Differentiating with respect to X', . dO ___ cot X' _ cot X' sin sin (0 0') , ,. ' d X' cot (0 - 0') - cot " sin0' Differentiating with respect to /, since / and X' are similarly involved in the logarithmic equation, we have by (16), dO _ cot / sin sin (0 0') dl ~ ~ by the Observation of a Lunar Distance. 301 So by differentiating with respect to P, dO _ cot P sin sin (9 0') , . d~P ~ "liiTe 7 "" Again, resuming the equation (7), viz. cot X = (cot X' sin P cos / cosec X') sin Q cosec 6', which, since is a function of 0', X', /, and P, shows that X is a function of the same quantities, we have to the first order of small variations, To obtain conveniently the partial differential coefficients, the logarithmic equation of (7) will be made use of, viz. Log cot X = Log (cos X' - sin P cos /) + Log sin - Log sin 0' - Log sin X'. Differentiating this equation with respect to 0', dX de sec X cosec X , = cot - cot a a And by (1 5) -7-7- = sin cosec 0' cos (0 - 0') (I Hence 7-7- = sin cosec 0' sin X cos X 3111 (0 0') - - - - (19) a Differentiating with respect to X', d X sin X' d - sec X cosec X -^ = - _,___ _ cot X +^0-^-, But ^ W> cos V - sin P cos/ = tan X sin Q cosec Q> cosec X And by (16), -^7 = cot X' sin cosec 0' sin (0 0') , i Substituting these' values it will readily be found that sin V Differentiating with respect to / C S . d X sin P sin / a sec X cosec X j-r = -- r/ - = =K -- j + cot -r-r d I cos X' sm P cos / n d I But by (7), cos X' - sin P cos / = tan X sin B COS6C B ' COS6C X ' (IB And by (17), -T-T- = cot / sin cosec 0' sin (0 0') d X sin P sin sin X . Hence -77 = - . fl , . ., (sin X sin / + cos X cos / cos 0)- - - (21) a i sin v sin A/ , 302 On the Correction of a Longitude determined Lastly, differentiating with respect to P, . d X cos / cos P do sec A, cosec A, 7^5- = -- r-i - : ^ - r 4- cot d d P cos X' sm P cos / ~ But as before, cos X'-sinPcos/ = tan X sin e cosec e ' cosec X ' And by (18), -- = cot P sin d cosec 0' sin (0 - e') = cos P sin 2 cosec 0' sin I cosec X' by (3). d X cos P sin sin X d P sin 0' sin Hence -- = " e T sin " x 7 " (sin X cos / - cos X sin / cos 0) (22) We have next to obtain expressions for the small variations 5 0', S X', J /, and 5 P. Since by supposition the Hour Angle is East, 8' = R'- I HenceS0' = SR'-H Suppose now that the true Longitude of the place of observation is equal to the assumed Longitude + r, an East Longitude being reckoned negative. Also let the true Right Ascension of the Zenith be + t. Then the correction of the assumed Greenwich Mean Time of observation is p (t + r), p. being the factor [9,99881] which converts an interval of Sidereal Time into an interval of Mean Solar Time. Hence if t and T be expressed in seconds, and if a be the increment of the Moon's Geocentric R. A. at the time of observation in one second of Mean Time, the cal- culated Geocentric R. A. requires the correction + p, a. (t + r) on account of the error of the assumed Greenwich Mean Time. Let a be expressed in seconds of arc, and let the correction of the Tabular R. A. of the Moon at the same time be x in seconds of arc. Then S R' = p a (t + T) + x The correction (& ) of the Right Ascension of the Zenith expressed in arc is 15 1. Hence S0' = n<*(t + T) - 15* + x So if y6 be the increment of the Moon's N. P. D. at the time of observation in one second of Mean Time, and y be the correction of the Moon's Tabular N. P. D., S V = p fi (t + r) + y The values of a and y6 are readily obtained after the calculation of the interpolated values of R' and X'. For by the usual formula of interpolation to second differences, h h* , h h* R' = a , + b, |j + c, jp- X' = a 2 + 6 8 jj + c 2 jji h being the algebraic excess of the time of observation above the nearest Epoch, and H being the common interval (l h ) between the Epochs, both expressed in seconds. Hence, R' being in time, by the Observation of a Lunar Distance. 303 *'* . Th H H* 15 rfX' 6. Zc,h r . dh The correction / is the sum of the correction of the assumed astronomical co- latitude, and the correction of the angle of the vertex. Let us suppose that & / = v in seconds. The error of P depends on the error of the Tabular Equatorial Parallax, the error of the assumed distance of the place of observation from the Earth's centre, and the error of the assumed Greenwich Mean Time of observation. By varying the symbols in equation (1) we have, cos P X P = p sin P' + p cos P' J P', or, omitting small quantities of an order that may be neglected, s p = p' $ p + p a P\ * If the true Equatorial Horizontal Parallax of the Moon for a given distance from the Earth's centre has been ascertained to be P, (1 -f- 0,001 yw t ), P t being the corres- ponding value in the NAUTICAL ALMANAC, the true Equatorial Horizontal Parallax at the time of observation may be taken to be P' (1 -f- 0,001 m^. Also if i be the increment of the Equatorial Horizontal Parallax at the time of observation in one second of Mean Time, the correction of P' for error of the assumed Greenwich Mean Time is -f- p. t (t 4- T). Hence S P' = 0,001 P' m l + n i (t -f r). Let the true distance of the place of observation from the Earth's centre be p (i 4. o,001 z 2 ), so that S p = 0,001 m z p. Then 5 P = 0,001 m t p P' + 0,001 m l p P' + pt p (t + T). Hence, putting m for m l + m s and supposing that p = I in the third term, which is very small, $ P = 0,001 m P + p i (t + T). If the interpolated value of P' be . h' h n and h', H' be expressed in seconds, then with sufficient approximation, dh' (25) For the purpose of facilitating the logarithmic computation by the eight formulae (15 22), and for the sake of brevity of expression, the following substitutions will now be made : 304 On the Correction of a Longitude determined sin 9 L sin X L = ^Te' Q = TirTAT = Q cos X N = Q sin X A ^ B - C d& P de de' d\' Tl = ' A '_ ^_ X TV d ^ P , d\ J j at 15 = -JT/ O = -7-= D x 1000 dP By these substitutions the formulae are changed to the following : A = L cos (0d f ) ............... !_._ B = - L cot X' sin (0-9') ............... (27) C = L cot Jsin (9-9') ................. / 28 \ D = 0,001 PL cot P sin (9-9') ............. (29) A' = M sin X' sin (9 9') ............... _ /^QN B' - N sin X' -f- M cos X' cos (9-9') ........... ( 31 \ C' = N sin P sin I M sin P cos / cos 9 ........ (32) D' = 0,001 PN cos P cos/- 0,001 P M cos P sin /cose ____ (33) Most of the logarithms required for computing by these formulae, will have been already obtained in the calculation of 9 and X. Now since 5 R = 5 Z, + 5 0, by referring to the values which have been found for S 0, H, S 0', 5 X', $ /, S P, it will be seen that SR= Ibt + Adiaty + r) - 15*+ X ) + B (p ft (t + T ) + y) which equation takes the form, So the expression for 5 X is, 5 X = A' (p. a (t + r ) - 15 t -f a:) (34) - - - - (35) which takes the form, U = o'< + b'r + A'x + E'y + C'v + D' (36) and a' = ^ (A' a +B'6) - 15 A' + L' = b > - ISA' ...... (37) sin c by the Observation of a 'Lunar Distance. 305 By making all the symbols vary in equation (11) we obtain, sin c & c = (siii X cos 7 cos X sin 7 cos >)) X 4- (cos X sin 7 sin X cos 7 cos r)) 7 4- sin X sin 7 sin tj j Hence, as may be readily shewn, S c= I sin (7 4- X) sin 2 4- sin (X 7) cos 2 4- ( sin (7 4- X) sin 2 sin (X 7) cos 2 V-~ 4- sin X sin 7 sin -n ^ sin c Suppose the correction of the assumed R. A. of the Sun, Planet, or Star, to be e in seconds of space, and the correction of the assumed N. P. D. to be/. Then 7 = /, and TJ = $ R e, or e S R, according as the Moon is more Eastward or Westward than the other body. Putting d for the difference between the arcs X and 7, let the three quantities N t , N 2 , N 3 , be calculated by the formulae ^ sin d 2 T] sin A sin 7 sin rj In the case of an Occultation, or Solar Eclipse, on account of the small values of c, d, and 17, the following formulae may with sufficient accuracy be used instead of the foregoing. (41) N 2 = sin (7 + X) .... (42; N 3 = - sin Xsin7 -- ............ - (43) c r" being the number of seconds in an arc equal to radius, and c, d, ij, being all expressed in seconds of space. Now let T = N 2 N! and U = N 2 + N 15 the upper or lower sign being taken according as X is greater or less than 7 ; and let \V = N 3 , the upper or lower sign being taken according as the Moon's apparent place is more Eastward or Westward than that of the other body. Then 5 c = W ($ R - e) + T U + U/ The error of the Moon's calculated apparent Semidiameter (S) depends on the error of the Tabular Geocentric Semidiameter, and the error of the assumed Green- wich mean time of observation. It has been shewn that sin 8 sin X sin 0' sin X" _ or fc 306 On the Correction of a Longitude determined Hence 5 S = Q S S' + S' $ Q If the true Geocentric Semidiameter for a given distance from the Earth's centre be known from exact measurements to be S t (1 -J- 0,001ra), Sj being the corresponding value in the NAUTICAL ALMANAC, the true value at the time of observation may be taken to be S' (1 + 0,001 ri). Also if icbe the increment of the Geocentric Semi- diameter at the time of observation in one second of mean time, the correction of S' for error of the assumed Greenwich mean time is + p K (t -f- T). Hence J S' = 0,001 S'n + n K (t + T) and Q J S' = 0,001 Sn + JJL K (t + r), since Q = 1 nearly. * sin sin X The equation Q = gin tf sin v gives, -^ = cot J 8 - cot 0' J 0' + cot X S X - cot X' X'. By considering only the parts of 5 Q and $ X which depend on 5 Q' and J X', which is allowable, the following result to the first order of small quantities may be arrived at. T " = - sin 2 X sin (0 - 0') 5 0' - sin (X - X') J X' It will in no case be necessary to take account of the term involving 5 X', (which c term when multiplied by -77 becomes exceedingly small), and it will suffice to put -15*forS0'. Thus S. sin* X sin (0- Hence, if a = ^-sin 2 X sin (0 - 0') - --- ..... (44) we have S S = 0,001 S + jne(* + r)+a/ If the interpolated value of S' 'be h' h* a * 4 ~H~ + C * H 71 " and h', H' be expressed in seconds, then very nearly, dh r ~ H' We are now prepared to substitute in the equation of condition (13), the values of S c and S S which it was proposed to investigate. The substitution gives, e + $ * = W ($ R - ) + T $ X + U/- o,001 S n - p K (t + r ) - GJ t, or, putting for S R and 5 X their values obtained above, by the Observation of a Lunar Distance. 307 + T (a' t + b f r + A'ar+ B'y + C'v+D'wi) -(/iic + Gj)<-/iKr-W + U/- 0,001 Sn Consequently, if the values of [1], [2], [3], [4], [5], [6], be obtained by the formulae, [1] = aW + a'T-/iK-t3 [2] = bW + b'T - pK [3] = AW + A'T [4] - B W + B' T [5] = C W + C' T [6] = D W + D' T the final equation, completely calculated is, e + 5 * = [1] t + [2] r + [3] x - We + [4] y + U/+ [5] v + [6] m - 0,001 S n. For the sake of simplicity the Hour Angle has all along been supposed to be East. For Hour Angle West, 0' = 2, R', the calculations of and X are the same as for Hour Angle East, R = Z, 0, and the signs of B, C, D, A', and a, are changed by the change of sign of and Q'. No other alterations are required for adapting the formulas to this case. The foregoing investigation has been conducted so as to take fully into account any error in the elements of the calculation that can possibly affect the calculated result of the observation. This degree of exactness may be required in the case of an Occultation, especially the disappearance or reappearance of a star at the Moon's dark limb, which is an observation admitting of great precision : but in the ordinary case of a Lunar Distance much of the calculation may be omitted, as relating to quantities too minute to be worth taking into account. To facilitate the use of the method above investigated, I propose now to collect the formulas of calculation, and arrange them in the order in which they are to be employed, and at the same time to point out those parts of the calculation which may be omitted in the case of a Lunar Distance. The formulae, according to their relation to each other, will be contained in separate articles numbered I, II, III, &c., for the sake of future reference. I. The initial calculations are the interpolations of R', X', P', S', to second differences from the NAUTICAL ALMANAC. The formulae are, R' = , + *, A + Cl ^_ X' = 2 + b* A+ cj^ P' = 3 + ^ +Ca ~ S' = , may be taken from Tables of the values of these quantities calculated for different latitudes on an assumed ellipticity. See Appendix to the NAUTICAL ALMANAC for 1836, pp. 57 and 58. sin P = p sin P' sin P sin / G - tan (6 - 6') = sin A/ G sin 0' 1 - G cos 0' III. Formulas for calculating the Moon's apparent N. P. D. (X). sin P cos / tan = : r-y = G cot / sin X' sin ', L cos (X' + 0) cot X = - } . x , cos sin X' IV. Formulae for calculating the Moon's apparent Semidiameter (S). L sin X ^"shTT 7 " S = Q S' V. Formulae for calculating the apparent Distance between the centres of the two bodies (c). The Moon's apparent R. A. (R) is -f- or 0, according as the Hour Angle is East or West. The difference between R and the apparent R. A. of the other body is ij. cos c = cos X cos 7 + sin X sin 7 cos rj. Transformations of this formula convenient for logarithmic computation are well known. Tables of Addition and Subtraction -Logarithms might be used to cal- culate by it in its present form. In the case of an Occultation, or Solar Eclipse, d being the difference between X and 7, and c, d, ij, being expressed in seconds of space, = d (\ + Y sin x sin y\ * by the Observation of a Lunar Distance. 309 Or, making use of a subsidiary angle, tan x = -j * / sin X sin 7 c = d sec X- VI. Formulae for calculating the co-efficients of /, r, a:, y, v, m, in the expression for $ R, viz., It will be advisable to commence this part of the calculation by finding log sin (0 0') by the formulae Log q = log tan (0 0') Log sin (0 e') = log q -f- log cos (0 0'), Log tan (00') being taken as deduced by the formulae of Art. II., and the upper or loiver sign being attached according as the hour angle is East or West. By using the resulting value of log sin (0 0') in all the subsequent calculations, no farther attention to the double sign is necessary, the same formulae applying whether the Hour Angle be East or West. As it is known that the correction & P of the Horizontal Parallax will always be p a small quantity, it will be sufficiently accurate to take -77 cot P = 1 in the value of D. A = L cos (0-0') B=-Lcot X' sin (0-0') C = L cot /sin (0-0') D = 0,001 r" L sin (0- 0') = [2,31443] L sin (0- 0') = 6-15 (A-l). Iii the expression for &, P must be in seconds. For a Lunar Distance, the term containing i is to be omitted, and, generally with sufficient accuracy, A = l, B = 0, a p. a = b. VII. Formulae for calculating the coefficients of t, r, x, y, v, m, in the expression for S X, viz., U = a'* + Vr + A'x + B'# + C'v + D'm. For the reason above given we may put cos P = 1 in the expression for D'. M = Q cos X A' = M sin X' sin (0 - 0') N = Q sin X B' = N sin X' + M cos X' cos (0 - 0') = n, -f ^ C' = - sin P (N sin / 4- M cos / cos 0) = - sin P (n\ -f ' a ) D' = 0,001 P (N cos / - M sin / cos 0) = 0,001 P (n'\ + " a ) a' = b f - 15 A'. 310 On the Correction of a Longitude determined P, as before, is to be expressed in seconds. For a Lunar Distance, the term con- taining i is to be omitted, and, generally with sufficient approximation, A' = 0, B' = 1, a' = p ft = b'. VIII. Formulae for calculating T, U, W, and ts. For a Lunar Distance, sin d cos 2 - ft-i. 3 *- sin c sin (7 -f- X) sin 2 y sin c sin X sin 7 sin rj sin c For an Occultation, or Solar Eclipse, N 2 = j-^ sin (7 + X) = [4,08351] ^-sin (7 + X) N 3 = sin X sin 7 c c, d, and ij, being in seconds of space. T = N 2 -4- N A or N 2 N, \ according as the Moon's Apparent N. P. D. is U = N 2 N! or N 2 + N, f greater or less than that of the other body. W = -f N 3 or N 3 , according as the Moon is more Eastward or more Westward than the other body. 1 e o GJ = jj- sin 2 X sin (6 - 6') = [5,8617] S sin 8 X sin (8 - 0'). For a Lunar Distance, the calculation of & may be omitted. IX. Formulae for calculating the co-efficients of t, r, x, y, v, m, in the Final Equation, viz., + $* = [1] < + [S] r + [3] x - We + [4] y + U/+ [5] v + [6] m - 0,001 S n. [1] = a W + a' T - ^ K - ts [2] = b W + V T - fjL K [3] = A W -f A' T [4] = B W + B' T [5] = C W + C' T [6] = D W + D' T For a Lunar Distance, p K and CD are to be neglected. In general, e= A + S 4- s c. For the beginning or end of a Solar Eclipse, e = S + s c ; for the occultation of a Planet, e = S s c, according as the contact was exterior or interior ; for the occultation of a Star, e = S c. by the Observation of a Lunar Distance. 311 The correction (S s) of the Tabular Semi-diameter of the Suri or the Planet may be left out of consideration in an observation of a Lunar Distance, as being small compared to the probable error of the observation. The small quantities t, 7f> Qnrn T off 1 4- Q 7^211 b* _ . _ _ 9 31046 oum i^og T C7,/ 0,\. J. Los 30 + A "ihA.^ Lo ff 2 i a i 004. ^ H* " Tncr h - 1 1 ^Q6 " g H 2 Loa-A - - 1 1 ^Q6 - ft ft^^l iJUg /t "TjOff f _ - Q 7782 Log d - - - - Sum = Log ^ + 6,3692 Sum = Log^ - - -f 6,1262 312 On the Correction of a Longitude determined .'. ^j 1 = 4- o"56508 .-. |p = - o",20439 ??* = + 0,00023 = + 0,00013 Sum = = -f- 0,56531 Sum = ft = - 0,2042( A. C. Log H' h 5,3645 A. C. Log H' h 5,3645 Log 6 3 - 1,0917 Log& 4 - 0,5250 Sum = Log i - - 6,4562 Sum = Log K - - 5,8895 It is unnecessary to take out the values of i and K. 2. Calculation of e by the formulae in Article II. Right Ascension of the Zenith in arc () - - 287 42 49,05 Geocentric R. A. of the Moon in arc (R') - - 336 57 3,45 Difference = the Hour Angle (0') 49 14 14,40 The Hour Angle is East. o / // Assumed Astronomical Co-latitude 37 47 8,37 Assumed Angle of the vertex Oil 12,00 Sum = Assumed Geocentric Co-latitude (/) - 37 58 20,37 Assumed Log p - - - -f 9,9990916 A. C. Log G cos 0' \- 2,1579647 Log sin P' - .... 4. 8,2376810 _ZU__ A. C. Log (1 -G cos 6') -f 0,0030292* Sum = Log sin P- h 8,2367726 Log G + 8,0271706 n 0' -f 9,8793371 9,9986753 A. C. Log sin V ... + 0,0013247 Log sin / ...... + 9,7890733 Log sin P ...... + 8,2367726 o , 7 ' 9 95369 .-. e - e' = o 27 54,76 Sum = Log G- - - - + 8,0271706 and 0' = 49 14 14j40 Log cose' ..... + 9,8148647 Sum = Log G cos 6' - + 7,8420353 Sum = 9 = 49 42 9,16 Also P = 59' 18",11 = 3558",!! 3. Calculation of X and S by the formulae in Articles III. and IV. + 8,0271706 . 04653,14 ..... +0,1076227 Sum = Log tan - - + 8,1347933 Sum = * Taken out of a Table of Subtraction-Logarithms, the argument being the Logarithm im- mediately above. 9 by the Observation of a Lunar Distance. 313 Log sin -h 9,8823521 A. C. Log sin 0' h 0,1206629 Log sin X 4. 9,9981498 A. C. Log sin X' - - + 0,0013247 Sum = Log L - - - + 0,0030150 LogL 4- 0,0030150 Log sec + 0,0000404 \ A. C. Log sin X'- - - -f- 0,0013247 Sum' = Log Q . . - 4. 0,0024895 Log cos (X' + 0) - - - 8,9617724 Log S' + 2,9874786 Sum = Log cot X - - - 8,9661525 Sum = Log S - - - + 2,9899681 .-. X = 95 17' 5",82 .-. S = 977",17 4. Calculation of c by the approximate formulae in Art. V. Assumed apparent N. P. D. of Star (7) = 95 1 2,30 X = 95 17 5,82 Difference (d) = 16 3,52 = 963", 52 O I II Z,= 287 42 49,05 = 49 42 9,16 Hour Angle being East, R = 4- = 337 24 58,21 Assumed apparent R. A. of Star in arc = 337 26 59,55 Difference (r,) = 2 1,34 = 121 ",34 Log d ..... -f 2,9838607 A. C. Log tan 2 x - + 1,8032309 A. C. Logd ---- h 7,0161393 Log sec 2 x ----- h 0,0067789* Logij ..... 4- 2,0840040 _ _ \ __ Log sec x --- - + 0,0033894 d ...... + 2,9838607 ^ ? Sum = Log - + 9,1001433 2Log^ ----- h 8,2002866 .-. c = 97W Sum = Log c ---- h 2,9872501 c = 97W S = 977 > 17 Log sin X - - - + 9,9981498 Log sin 7 ---- -f 9,9983327 .'.S c= +6,10 = 6 Sum = Log tan 2 x + 8,1967691 5. Calculation of A, B, C, D, , , by the formulae in Art. VI. Hour Angle being East, Log q = -f- Log tan (0 0'). Log q ........ + 7,90954 Log L ........ + 0,00302 Log cos (0 - 0') - '- - - + 9,99999 Log sin (0-0') ---- + 7,90953 - Log cot X' ..... -f. 8,89333 Sum = Log sin (0 - 0') - + 7,90953 Log L 4- 0,00302 Sum = Log B + 6,80588 Log cos (0-0') + 9,99999 Sum = Log A 4- 0,00301 * Taken out of a Table of Addition-Logarithms, the argument being the Logarithm imme- diately above. 314 On the Correction of a Longitude determined Log L-f Log sin (0-0') +7,91255 Log ; 001 P ..... +055122 cot/ ....... +0,10762 Sum = Log C + 8,02017 Log L sin (0 - 9') - - - + 7,91255 Constant Log +2,31443 A - C - Log 0,001 P --- + 9,4488 +9,9988 -6,4562 Sum = Log -JLL . , _ 5;9038 Sum = Log D + 0,22698 Log D + o,2270 + 9,99881 Sum = Lo J ^f~ - ~ 6,1308 Log +9,75229 ' P A a =+ 0,56769 Sum = Log p a .... +9,75110 ^ B =- 0,00013 Log A + 0,00301 J- 000 P P * = _ 00014 P Sum = Log /z A a - - - + 9,75411 Sum = b = + 0,56742 Log f, + 9,99881 also A = + 1.00696 LOST /8 -------- - Q31018 1 (\ ( A i \ ' and - 5 (A - 1) = - 0,03480 Sum = Log fi ft 9,30899 Log B . + 6,80588 S " m = ~ 15 (A - 1) = - 0,10440 and b = + 0,56742 Sum = Log fjL B ft 6,11487 ' Sum = a = + 0,46302 The numbers answering to Log B, Log C, and Log D will not be required. 6. Calculation of A', B', C', D', 6', ', by the formula- in Art. VII. L g Q + 0,00249 Log M _ 8 96680 L cosX - 8,96431 Log cos V ..... 1 8 , ? 89201 Sum = Log M ... -"7,96680 L g COS ^ ~ e ') + 9,99999 Log sin X' + 9,99868 Logsin(e-e')- - - - + 7,90953 Sum = L g *' ' ' ' + 7,85880 Sum = Log A' 6,87501 - + 9,75110 i--- = + 0,99844 - - - = + 0,00722 Sum = Log/zA'a - - - 6,62611 LogQ Log sin X + ' = + 1,00566 + 0,00249 + 9,99815 LogB'- Sum = Log N + L g sin x ' + 9,99868 Sum = Logw,. _f_ 9,99932 + o,00245 - 9 ' 308 " Sum = P/y6 - - - 9,31144 by the Observation of a Lunar Distance. 315 Log N Log sin I Sum = Log*',- - - Log coil + 0,00064 + 9,78907 4- 9,78971 + 0,10762 Sum = Logw", - - - + 9,89733 LogM 8,96680 Log cos / Log cos Sum = Log n\ - Log tan / Sum = Log n'\ - - + 9,89670 - - + 9,81074 - - - 8,67424 - - - 9,89238 - - + 8,56662 n\ = + 0,61618 ' 8 = - 0,04723 n\ 4- n\ = 4- 0,56895 Log (n\ 4- ',) ---- + 9,75507 - Log sin P - - - - -- 8,23677 Sum = Log C' ----- 7,99184 The numbers answering to Log C' and Log D' will not be required. w", = + 0,78946 n" z = + 0,03686 + n "v = + 0,82632 Log (n'\ + ",) - - - Log 0,001 P - - * - - Sum = Log D' - - - - 1000 /At 4- 9,91715 + 0,55122 + 0,46837 - 5,9038 - 6,3722 IQOOD'/tt P - 0,00024 and A' /A a = - 0,00042 B'/A/8 = - 0,20485 Sum = b' = - 0,20551 Also - 10 A' = - 5 A' = /. - 15 A' = and b' = 4- 0,00750 4- 0,00375 4- 0,01125 0,20551 Sum = a' = - 0,19426 7. Calculation of T, U, W, Q by the approximate formulae in Art. VIII. The Moon has greater N. P. D., and is more Westward, than the Star. A. C. Logc - 4-7,01275 Log*) ----- h2,08400 Constant Log +5,8617 Logrf- - - - 4-2,98386 A. C. Log c - 4-7,01275 2 Log sin X - 4-9,9963 L g sinX --+9,99815 Log sin(0-0') 4-7,9095 ^ . _ ^^ Log S - - - +2,9900 r l 4-9, 7 = 95 1' 2' X = 95 17 6 74-X = 190 18 8 Sum = Log N 3 4-9,09323 Sum = Log a 4-6,7575 Log K - - - 5,8895 N 8 = -0,00000 - - - 4-9,9988 2Logrj - - - 4-4,16801 A. C. Logc - -f 7,01275 Constant Log- 4-4,08351 = N 8 4-N,= 4-0,99222 = N 2 -N t = -0,99222 = LogN 2 -4,51674 W = -N 3 = -0,12395 - 5,8883 = -0,00008 = +0,00057 = +0,00049 316 On the Correction of a Longitude determined 8. Calculation of [1], [2], [3], [4], [5], [6] by the formulae in An. IX. Logo- - - - 4-9,66560 Log b - - - - +9,75390 Log A - - - -f-0,00301 LogW ---- 9,09323 LogW - - - -9,09323 Log W - - - -9,09323 LogaW - - -8,75883 Log b W ---- 8,84713 Log AW --- 9,09624 Loga' ----- 9,28838 Log b' --- -9,31283 Log A' --- -6,87501 LogT- - - - +9,99661 Log T - - - +9,99661 Log T - , - +9,99661 Loga'T- - -- 9,28499 Log b' T --- -9,30944 Log A' T - - -6,87162 'T = -0,19275 b'T= -0,20391 aW = -0,05739 bW = -0,07033 A'T = -0,00074 -(/iK + t3)= -0,00049 -IJLK= +0,00008 AW = -0,12481 Sum = [1] = -0,25063 Sum = [2] = -0,27416 Sum = [3] = -0,12555 LogB ----- h6,80588 Log C ---- - +8,02017 Log D ---- hO,22698 LogW - - - -9,09323 LogW ---- 9,09323 LogW ---- 9,09323 LogBW - - -5,89911 LogCW - - -7,11340 LogDW- - -9,32021 ' - - - +0,00245 LogC' --- - -7,99184 Log D' ---- f-0,46837 LogT --- +9,99661 LogT --- +9,99661 LogT - - : +9,99661 LogB'T --- +9,99906 LogC'T ---- 7,98845 LogD'T- - +0,46498 B'T= +o,99784 C'T = -0,00974 D' T = +2,91729 BW = -0,00008 CW= -0,00130 DW= -0,20903 Sum = [4] = +0,99776 Sum = [5] = -0,01104 Sum = [6] = +2,70826 FINAL EQUATION : + 6",10 = - 0,2506 t - 0,2742 r - 0,1256 x + 0,1240 e + 0,9978 y - 0,9922/ - 0,0110 v + 2,7083 m - 0,9772 n To ascertain the correction of the Longitude given by this equation, I shall now substitute for the other small corrections the most probable values that I have been able to obtain. By the result of observations of the Moon on the meridian at Greenwich on the same day (Sept. 14), x = - 20",70 and y = + 9",19- Taking the place of K Aquarii from the Twelve-year Greenwich Catalogue, e = - 0",90 and/= + 2",65. Adopting + 2",6l for the correction of the Moon's Semi-diameter as determined by Greenwich Observations (See Introduction to vol. for 1847, p. ci.) the resulting value of n is 2,773. Adopting Henderson's correction of Burckhardt's Constant of Parallax, viz. + 1",30, (Memoirs of the Royal Astronomical Society, vol. x., p. 294) the value of w 8 is + 0,380. by the Observation of a Lunar Distance. 317 The ratio of the Earth's axes assumed by Henderson is that of 299 to 300, while the ratio employed in the foregoing calculation is that of 297 to 298. The correction from this to the former ratio gives m l = + 0,014. Hence m, -f m s = -f- 0,394, which is the value of m. The alteration of the ellipticity requires the angle of the vertex to be corrected by 4",47, which is the value of v, the astronomical co-latitude being supposed to require no correction. As the observation was considered to be very exact, it will be supposed that t = (X By substituting these values the equation becomes, + 6,'lO = - o'!2742 r 4- 2,600 - o'l!2 -f &170 - 2,629 4- 0,'o49 + l"o67 - 2,707 or, 0",2742 T = + 1",34. Hence the correction of the Longitude by this observation is -f- 4 9 ,89- I have no ground for thinking that the Longitude of the Cambridge Observatory requires a correction to any such amount. The instance is evidently unfavourable to the determination of the Longitude on account of the small value of the multiplier of r. Slight errors in the adopted places of the Moon and the Star might account for the above result without supposing any error in the assumed Longitude. The result, however, serves to show the advantage of taking account of small corrections which the data of calculation may require, whether the calculation applies to an Occupation or a Lunar Distance ; for on the supposition that none of the data except the assumed Longitude required correction, we should have had, - 0",2742 T = + 6",10, or the correction of the Longitude = 22 S ,25. o But the assumed Longitude is really not one second in error ; consequently, as the observation was probably not in error more than a small fraction of a second, nearly the whole of the above result is attributable to errors in the elements of the calcula- tion, and will serve to indicate the effect of such errors independently of the degree of accuracy of which the observation was capable. In fact, as we have seen, by correcting those errors as nearly as was practicable, the result was reduced to -f- 4 S ,89- It may be remarked that this instance is confirmatory of the correction applied to the Moon's Semi-diameter. CAMBRIDGE OBSERVATORY, September 10, 1850. LONDON : 'tinted by WILLIAM CLOWES AND SONS, Stamford-street. , RETURN Astronomy/Mothemotks/Stotistics Computer Science Library 1 00 Evans Hall 642-3381 LOAN PERIOD 1 2 1 MONTH 3 4 5 6 ALL BOOKS MAY BE RECALLED AFTER 7 DAYS DUE AS STAMPED BELOW Rec'd UCB A/M/$ FEBH1986 UNIVERSITY OF CALIFORNIA, BERKELEY FORM NO. DD3, 1/83 BERKELEY, CA 94720 U.C. BERKELEY LIBRARIES