LIBRARY 
 
 UNIVERSITY OF CALIFORNIA. 
 
 GIFT OF 
 
 Class 
 
 V 
 
By Starlight 
 \ and Moonlight 
 
 With the Warner & Svvasey 
 
 Prism 
 Terrestrial Telescope 
 
 The Warner & Suasey C 
 
 CLEVELAND 
 
 Price 25 cents 
 
BY STARLIGHT 
 and MOONLIGHT 
 
 With the Warner & Swasey 
 Prism Terrestrial 
 Telescope 
 
 Some Easy Astronomical 
 Observations 
 
 
 
 
 The Warner & Swasey Company 
 
 CLEVELAND, OHIO 
 
 

 Copyright, 1909, by The Warner &> Swasey Co. 
 Cleveland, Ohio 
 
"// adds a precious seeing to the eye," 1 
 
 Shakespeare ; Love s Labour s Lost. 
 
 194838 
 
THE WARNER & SWASEY PRISM TERRESTRIAL TELESCOPE 
 
 Complete with 
 
 ALT-AZIMUTH MOUNTING, FOLDING TRIPOD 
 AND CARRYING CASE 
 
OF THE 
 
 UNIVERSITY 
 
 OF 
 
 The Warner C&> Swasey Prism 
 Terrestrial Telescope 
 
 This Porro Prism instrument represents the 
 highest development in Terrestrial Telescopes. 
 Its relation to the ordinary telescope is the same 
 as that of our Prism Binocular to the old type of 
 field-glass. It is remarkable for its large field, 
 brilliant illumination and clear definition. 
 
 The objective is 2 inches in diameter, clear aperture. Two 
 eye-pieces are provided, magnifying respectively 25 and 50 diam- 
 eters. The telescope tube and the alt-azimuth mounting are made of 
 aluminum. The folding tripod is of carefully selected ash. All are 
 contained in a neat leather-covered carrying case; total weight 
 only twelve pounds. Weight of telescope with its tripod and 
 mounting, apart from case, but six and a half pounds. 
 
 The high quality of its optical equipment, and the simplicity 
 and adequacy of its mechanical provisions, make it superior to any 
 similar telescope upon the market for the camper, the traveler, the 
 motor-tourist, the surveyor, or the marksman upon the rifle-range. 
 It is especially adapted for porch, seaside and general use. 
 
 While thus designed strictly as a terrestrial telescope, its 
 purchasers have also found it of much interest and value in the 
 field of amateur astronomy. It is not presented as in the tech- 
 nical sense an astronomical telescope; and yet its quality is so 
 superior that its efficiency is actually greater than that of many 
 larger astronomical telescopes heretofore offered to the public. 
 The ease with which it can be moved from place to place in the 
 observation of moon and stars, its sharp definition and breadth of 
 field, combined with the precision and steadiness with which the 
 instrument may be "pointed" and controlled, have brought many 
 expressions of satisfaction from those who having first purchased 
 it as a terrestrial telescope have subsequently tested it in their 
 observations of celestial objects. To respond to the interest and 
 the demand thus indicated, and to illustrate, for beginners, some 
 of the simple astronomical uses of the Warner & Swasey "Prism 
 Terrestrial," this little booklet has been prepared. 
 
 Our long experience in making "Optik Tubes" of all sizes, 
 from the great Lick and Yerkes Telescopes to the Telescopic Gun 
 Sights, Range Finders, Sextants, etc., used by the Army and Navy, 
 especially qualifies us to develop from both a scientific and prac- 
 tical standpoint, the highest type of Porro Prism Telescope. 
 
By Starlight and Moonlight 
 
 WITH THE WARNER C& SWASEY 
 PRISM TERRESTRIAL TELESCOPE 
 
 Introductory 
 
 The beginner naturally asks, "What is there to see? What 
 objects in the sky will my telescope reveal?" It will help toward 
 an appreciation of what his little instrument will do for him, if 
 we can first help him to understand some of the things which even 
 the largest telescope in direct proportion to its excellence will 
 not do for anyone. 
 
 There are results which are mathematically as impossible for 
 an optical instrument as for a fine watch to tick seventy-five sec- 
 onds to the minute. Your telescope cannot work well through a 
 misty atmosphere, or through air heavy with cloudiness or smoke. 
 It will not work well if you permit the steadiness of your tripod 
 to be affected by the winds, or if when you place it on your 
 porch the floor on which it rests is shaken by heavy walking. 
 Inasmuch as the atmosphere close to the earth is more subject to 
 disturbance and impurity than the air a little higher up, your in- 
 strument will work better on objects at a slight altitude than on 
 objects lying close to the horizon. 
 
 Yet even this two-inch instrument (modest indeed as com- 
 pared to those largest telescopes of the world the great instru- 
 ments made by The Warner & Swasey Company for the Lick and 
 the Yerkes Observatories) will give you gratifying results. There 
 is a peculiar fascination in being easily able to point your instru- 
 ment at a bright star and to find perhaps to your surprise that 
 it is not a single star, but a "double" or a "triple." It is even more 
 charming to be able to discern in a double star the contrasted colors 
 of the components, one, perhaps, being a golden yellow, the other 
 a distinct blue or a delicate emerald. 
 
 A few of the coarser doubles may be divided by a field-glass, 
 but everyone knows the difficulty in holding a field-glass steady; 
 and the power commanded by this little telescope is so much 
 greater than that available in a binocular that many doubles which 
 
no field-glass can divide will yield instantly to its persuasion. And 
 as your tripod does the holding, you can gaze at your leisure and 
 comfort into a steady field. 
 
 When Halley's comet comes again into view (it is scheduled to 
 reappear late in 1909, becoming still more conspicuous in 1910) the 
 possession of an adequate telescope, even though a small one, will 
 add much to one's pleasure in following its course. Objects, more- 
 over, that are quite familiar to us such a star-cluster for example 
 as the Pleiades assume through this little instrument a scope and 
 brilliancy quite unsuspected by the naked eye. Clusters, also, like 
 those in the sword-hand of Perseus and like the "Bee-hive" in 
 Cancer; nebulae like those in Andromeda and Orion; the four 
 greater satellites of Jupiter; the ring-formation and at least one 
 of the satellites of Saturn, and much of the strange and beautiful 
 topography of our own moon are brought within the range of 
 vivid interest and appreciation. A telescope that will easily divide 
 such double stars as Castor, and the Gamma in Virgo; that will 
 reveal so clearly the contrasted colors of such doubles as Mizar 
 and Albireo, and that will show even with a power of 50 the 
 trapezium in the sword of Orion, is not to be despised by anyone, 
 and holds for the beginner many possibilities of pleasure. 
 
 10 
 
Part I. 
 
 Single Stars Double Stars 
 The Planets 
 
Symbols 
 % First Magnitude Stars 
 
 Second Magnitude 
 
 Third Macjnifudf and Under 
 O Cluster 
 
 A Nebula 
 
 GUIDE MAP No. I. 
 
 This Map of #ie Northern Sky Joins, and overlaps the tops of 
 Maps II, III, IV. 
 
 On some evening when the air is clear and steady, place your 
 telescope on its simple mounting, and come with it out of doors. 
 Bring with you, for your greater comfort while observing, a plain 
 straight-backed chair, preferably without arms. 
 
 Let us face directly north, to get our bearings by the Great 
 Dipper and the North Star. During May, at 9 o'clock in the 
 evening, for example, you will find the Dipper just before you, 
 directly to the northward and very high up. During July and 
 August, you will see it further to your left in the northwest, the 
 handle following the bowl and the bowl turning slowly downward, 
 as its stars make their apparent revolution about the pole of the 
 heavens. Late in the autumn, you will find it low down, directly 
 to the north, its bowl turned upward; and in the winter, you will 
 see it climbing upward to your right, in the northeast, but with its 
 bowl turned toward the west. 
 
 In noting this apparent revolution of the Dipper, we have 
 taken 9 P. M. as the hour of observation. As it takes approxi- 
 mately twenty-four hours to complete its turning, we shall find it 
 at 8 P. M. less far advanced upon its course; at 10 P. M. or at 11 
 P. M., we shall find it proportionately further forward. A few 
 minutes' observation for an evening or two will make these direc- 
 tions clear ; but as many may wish to study more fully the motions 
 of the stars, and as all ought to have larger knowledge of the im- 
 portant constellations (an easy and delightful subject of popular 
 information) some elementary books of reference are given on 
 page 37 ; see also paragraph 9, page 36. 
 
 12 
 
First let us look at Mizar, the star marked Zeta () in the 
 bend of the Dipper's handle. The reader who is not familiar with 
 the characters of the Greek alphabet will quickly pick them up as 
 we go along; some of the stars have no other designations. 
 
 Quite near to Mizar you will note, if the air is clear, a little star 
 that may sometimes be seen with the naked eye. Using your 25 x 
 eye-piece, turn your telescope upon them. Be sure to get a clean, 
 sharp focus. You will observe at least four objects in the field. 
 You will see Alcor, the smaller star to which we have referred, and 
 another fainter star, and by looking closely at Mizar (the brightest 
 of the group), you will discover that it is a "double." Now, having 
 once found these in your telescope, slip in the 50 x eye-piece, and 
 the division between Mizar and its close companion will be clearer 
 still. (The magnitudes of the components are 2.4 and 4.2.) 
 
 Now let us look somewhat further from the pole, near the edge 
 of our little map, at a star which the Dipper's handle (if it were 
 continued in a curve) would quite enclose. This is Alpha in "The 
 Hunting Dogs" (Canes Venatici). It is sometimes called Cor 
 Caroli, the Heart of Charles, in honor of Charles I of England. 
 Your 25 x will show it to be a charming double. (The magnitudes 
 of the components are 3.1 and 5.7.) 
 
 In searching for a star with the telescope, it is well to use the 
 less powerful eye-piece. Having found the object, you can then 
 slip in the higher power if you desire. Let us now follow with our 
 eyes the general direction indicated by the "Pointers" in the bowl 
 of the Dipper. Not stopping, however, at the Pole Star, let us 
 continue the imaginary line as far again, right across the northern 
 sky. We are now in the neighborhood of the constellations Cepheus 
 and Cassiopeia. Almost at the center of Cepheus, we shall find 
 the little star Xi () ; magnitudes 4.4 and 6.5. You may find it a 
 little difficult. Turning, however, to one of the corners of the 
 house-shaped figure, we shall find an especially easy and very pretty 
 "double" in the star Delta (8) ; magnitudes 3.7 and 5.1, and we 
 shall find another in the head of Draco, the Dragon. From the 
 star Delta (8) in Cepheus let the eye project an imaginary line 
 to Alpha (a) in the same group continuing it approximately 
 the distance of the Dipper's total length. You will thus come 
 readily to the stars that mark the Dragon's head. The star Nu 
 (v) is the faintest of the four ; but even with your 25 x eye-piece 
 you will be rewarded by the brightness of its two components, 
 (magnitudes 4.9 and 4.9). 
 
 And now before leaving the northern stars let us return again 
 to the region right across the northern sky from the Great Dipper. 
 Still using your low-power eye-piece, sweep through the rich fields 
 of Cassiopeia till you reach the neighborhood of the star Alpha (a) 
 in Perseus. This is one of the most brilliant sections of the sky. 
 Note especially the star-clusters marked (X) and (h). They have 
 symbolized for ages "the sword-hand" of the hero Perseus. Of 
 course a larger instrument would give a more adequate impression 
 of their scope and splendor, but our little telescope will reveal much 
 of the beauty of the scene. 
 
 13 
 
Joins Map X 
 
 GUIDE MAP No. II. T/i/s Map Overlaps Map I at the Top and 
 Map III and IV at the Sides. 
 
 We have already spoken of the region of the sky in the neigh- 
 borhood of the star Alpha (a) in Perseus. We find Perseus in 
 the northeast late in August and the early autumn; in the north- 
 west during February and the early spring. At the right side of 
 Map II toward the top, you will find this part of the sky repeated, 
 for the tops of the oblong maps we now employ are "overlaps" 
 connecting the circumpolar stars with the other stars of the sky. 
 You will also see the star Beta ((3) or Algol, by name and you 
 will note that a line drawn from Beta (/?) to Alpha (a) will form 
 a right angle with one drawn to the star Gamma (y) in Androm- 
 eda. The latter is one of the most charming of all the double 
 stars (magnitudes 2.2 and 5.0) ; the colors of its components are 
 orange and a delicate emerald. It will repay close observation with 
 both your eye-pieces. 
 
 Next let us look at the well-known group called the Pleiades. 
 They appear in the east in the early evenings of late September, 
 reach their highest point above us early in January and continue 
 till April in the western sky. They are so far distant that their 
 light, traveling at the rate of more than 186,000 miles a second, 
 takes more than two hundred years to reach us. The average 
 unaided eye can discern but six or seven ; turn your little instru- 
 ment upon them using your 25 power eye-piece and you will see 
 the shining of hundreds. 
 
 Now let us turn our telescope upon the region about Alde- 
 baran, the red eye of Taurus, the Bull. The stars that here make 
 
 14 
 
the V-shaped figure which we see in our little map the point of 
 the V being at the star Gamma (y) are called the Hyades. The 
 group is not so compact as the Pleiades, but it is well worth exam- 
 ination. Note especially the little star Theta (0) quite near 
 Aldebaran (mags. 4.0 and 3.6). Many can divide it with the un- 
 aided eye. 
 
 Early in November, the stars of Orion begin to be seen in 
 our eastern sky. There is no other constellation quite so impres- 
 sive ; and from November till late in April, when it sinks below the 
 western horizon in the early evening, it is well-placed for easy 
 observation. Here as always begin with your eye-piece of low- 
 est power. First note the uppermost of the three bright stars in 
 Orion's belt the one marked Delta (8). It is an easy "double" 
 (mags. 2.4 and 6.8). Then turn to the little star just below and 
 to the right of the lowest star of the belt. We refer to the un- 
 marked star near to Zeta (). It is a "multiple" star (Sigma, <r) 
 and even with our little instrument you can clearly discern at least 
 three of the components (mags. 5, 6.8, 6.3). Next let us look a 
 little lower still, at the star Theta (0). This is a region of be- 
 wildering interest. Here you will clearly observe especially if the 
 moon be not shining so bright as to obscure the light of other 
 objects the beautiful, mysterious halo of the "Great Nebula of 
 the heavens." Almost at its center, if you will now use your 50 x 
 eye-piece, you will discern Theta's four components, for the star 
 is a "quadruple" (mags. 6.8, 7.9, 5.3, 6.8). Small as they will 
 seem, you will clearly observe them as separate points of light. 
 They form an irregular square the famous "trapezium" lying 
 close together in a dark space at the core of the enfolding radiance. 
 
 Just below, note the star Gamma (y) in Lepus (mags. 5.6 and 
 6.4) ; and to the left of Orion note the star marked 8 (mags. 4.6 
 and 6.7); and that marked 11 (mags. 4.3 and 5.7). These are 
 easy and pretty doubles. 
 
 We have looked at two of the clusters easily seen with the 
 unaided eye; now let us look at two which but for the telescope 
 not so many eyes would find. You will see the place of the first 
 of these, marked with the little circle, just below the bright star 
 Sirius. A little searching with your low-power eye-piece will soon 
 be rewarded by the sparkle of its "star-dust." The second is shown 
 nearer the top of our map, in the constellation Cancer. Its name 
 is Praesepe, "The Manger." You will find it slightly to one side 
 of an imaginary line drawn from Castor to Pollux and projected 
 southward. The myriad little stars of the cluster seem so busy in 
 their twinkling that it has often been called "the Bee-hive." 
 
 Among the "doubles" in this quarter of the sky are the star 
 Iota ( i ) just above the "Bee-hive" (mags. 4.2 and 6.6) ; the star 
 Zeta () in Gemini (mags. 3.7 and 7.0), and Castor itself, one of the 
 most beautiful of telescopic objects (mags. 1.9 and 2.8). The two 
 components form a "binary" system, being in slow revolution 
 about a common center. The companion stars will seem very 
 close together in so small a telescope, but with the 50 x eye-piece 
 and on a clear night, a good eye will easily divide them. 
 
 15 
 
Joins Ma/a I 
 
 G VIDE MAP No. HI. This Map Overlaps Map I at the Top, and 
 Maps IV and II at the Sides. 
 
 As with the other oblong maps, the top of this map joins Map I, 
 partly overlapping it and therefore showing some of the stars 
 that we noted on p. 12. Among these is the pretty "double" not 
 far from the Dipper's handle marked Alpha (a) in the constella- 
 tion Canes Venatici. We may now note also the very easy double 
 quite near it marked 15; its components being magnitudes 6.2 and 
 6.4. These stars are shown here near the upper border of our map, 
 about midway between the two sides. They come into good posi- 
 tion at the northeast about the middle of February, and though 
 rather high up in May, June and July, they are again well placed 
 for observation at the northwest during the evenings of August and 
 September. 
 
 Just to the south of them you will observe the pretty groups 
 or strands of stars called "Bernice's Hair." The name does not 
 appear, but you will see them on our map just to the right of 
 Arcturus. Sweep through them with your low-power eye-piece, 
 and you will be delighted with the spectacle. 
 
 Through the early evenings of spring we shall also find the 
 constellation Leo in our eastern sky. Leo is rather high up during 
 the evenings of April and May, but is again in good position in our 
 western skies during June and July. You will easily recognize it 
 by the "sickle" formed from the stars Regulus, Eta (77), Gamma 
 (y) , etc. First using your lowest power, let us look at the star Gamma 
 
 16 
 
(y). You will note quite near it a little neighbor-star, not its 
 double for it is connected with the larger star only in the line of 
 sight yet it presents a pleasing contrast in size and color. Now 
 change to the highest power eye-piece you have. This, if you have 
 a good eye and the atmospheric conditions are favorable, will show 
 you that Gamma (y), the larger star, is also a real double, a binary 
 the two components (mags. 2.6 and 3.8) being in slow revolution 
 about a common center. With the star Gamma (y) in Virgo (mags. 
 3.6 and 3.6) you will also need your highest power, but as the dis- 
 tance between the components is greater, even the beginner if the 
 night is good will be delighted with his success. With the power 
 of 50x, in our little instrument, it is one of the most charming 
 objects in the sky. 
 
 One of the easiest of the "doubles" among the early evening 
 stars of the spring and summer is Alpha (a), mags. 5.3 and 2.9, in 
 the constellation Libra. Libra rises in the southeast during May 
 and continues in our southern skies till it sets at the southwest in 
 October. We may also try the star Delta (8) in Corvus, though we 
 shall find this more difficult. Returning now to the top of our map 
 let us look in the region near Arcturus at the star Pi (TT) in 
 Bootes; mags. 4.6 and 6.0; and at Delta (8), mags. 3.5 and 8.2, in 
 the same constellation. Next, and to the left, you will see the stars 
 of Hercules. While this immediate region of the sky is too di- 
 rectly overhead for easy observation in the early evening of August, 
 it is in good position at the east during the early spring and at the 
 west during the early autumn. We shall need our highest power 
 in looking at Alpha (a) mags. 3.4 and 5.3, but even with our 
 25 x eye-piece we shall find a pretty double in the star Kappa (K), 
 mags. 5.3 and 6.5. And now let us follow the line indicated be- 
 tween Eta (77) and Zeta () till we come to the cluster indicated 
 by the little circle lying between them. It is globular in form, 
 and in a large instrument is most impressive. The elder Herschel 
 estimated the presence within it of 14,000 stars. 
 
 Turning again to the lower half of our map, at the left, let us 
 next note some of the objects in Scorpio. Rising at the southeast 
 in the month of May and continuing at the south through the early 
 evenings till they set in September at the southwest, the stars of 
 this superb constellation are always in fine position for the observer 
 of our summer skies. Use first your low-power eye-piece in sweep- 
 ing through the whole field of these stars. Then look using each 
 eye-piece in turn at the double star marked Nu (v), magnitudes 
 6.4 and 4.2; and then at Beta (), magnitudes 2.9 and 5.0. These 
 are easy to divide and yet sufficiently close to be very interesting 
 objects of their class. Follow, then, with your low-power eye-piece 
 the course of the Scorpion's tail. You will find the star Mu (//,) 
 and the region just below it well worthy of your study. The star 
 clusters of Scorpio and of Sagittarius (Map IV), some of which 
 are marked in our maps by the little circles, are not brilliant in a 
 small telescope, but the finding of a few of them will add much to 
 your appreciation of this region of the sky. 
 
 17 
 
Joins Map I 
 
 GUIDE MAP No. IV. TMs Map Overlaps Map TVo. 7 af the Top, and 
 Maps II and III at the Sides. 
 
 As we begin with the stars in Map IV let us again turn for a 
 moment to No. I, and note the position of the Dipper in relation 
 to some of the stars near the lower border of that map. As the 
 Dipper looms above us in the evening skies of May you will see, 
 low down and to the right, the stars of Lyra rising at the northeast. 
 
 In Map IV, at the top, you will now observe the repetition of 
 some of the objects of this region; you will note that Vega, the 
 leading star in Lyra, is between the constellation Hercules, on the 
 one hand, and Cygnus on the other; and you will see, further, that 
 all these stars hold always the same fixed position in reference to 
 the great Dipper. When the Dipper is high up these are in the 
 northeast; as the Dipper sinks toward the west these rise to the 
 meridian ; as the Dipper itself wheels again into the northeast, they 
 sink below the horizon at the northwest. To the beginner such 
 descriptions (see also p. 12 and par. 9 on p. 36) may sound a 
 little "complicated," yet if he will look for an evening or two at 
 the actual skies, glancing now and then at his little maps, he will 
 find few things more pleasurable than "the simplicity of the stars." 
 
 On a clear night Vega can always be identified by the rhomboid 
 ("the slanting oblong square") formed by the stars Delta (8), 
 Gamma (y), Beta (f3), and Zeta () Of these, all except the second 
 are double stars, the first named being the easiest to divide. The 
 components of Delta (8) are magnitudes 5.5 and 4.5. Beta is a 
 "multiple," only two of the components being within the range of 
 our instrument (magnitudes 3.3 and 6.7). The magnitudes of 
 
 18 
 
Zeta () are 4.2 and 5.8. We will now direct ourselves to the little 
 star Epsilon (e). It is a very easy double, magnitudes 5.0 and 6.0, 
 but of much more interest is the fact that each of these components 
 is itself a double, the two pairs being in very slow revolution about 
 a common center. The doubling of the doubles is beyond the 
 power of so small an instrument, but the knowledge of a fact so 
 unique in stellar history always gives a peculiar interest to them 
 as telescopic objects. 
 
 Not far from Lyra we find those stars of Cygnus, the Swan, 
 which form the Northern Cross. No star in the sky makes a more 
 beautiful or more satisfactory object for our telescope than "Al- 
 bireo," marked as Beta ((3) at the foot of this cross. The magni- 
 tudes are 3.2 and 5.3, and the contrasted colors a golden yellow 
 and a smalt blue make an especially fine contrast. The star 
 Omicron (o) is also an easy double (magnitudes 4.9 and 3.9), and 
 the star marked 61 (magnitudes 5.5 and 6.2) while perhaps requir- 
 ing your 50 x eye-piece for its division, is of interest as being the 
 nearest to our earth of all the stars in the northern sky. So far 
 away is it, however, that its light requires approximately eight 
 years in which to reach us! 
 
 Southward from Cygnus you will find another beautiful double 
 in Theta (6), magnitudes 4.5 and 5.1, of the constellation Serpens. 
 You can find it by extending an imaginary line from Eta (rj) to 
 Delta (8) in Aquila, and continuing it an equal distance. Still 
 further to the southward you will find a very easy double in Alpha 
 (a) of Capricornus; many can divide the components, magnitudes 
 4.5 and 3.7, with the unaided eye. A closer and more interesting 
 double is Beta (/3) of the same constellation, magnitudes 3.2 and 
 6.0; the colors being an orange yellow and a sky blue. 
 
 The stars of this region are well placed for observation 
 throughout the summer, rising at the southeast in July and con- 
 tinuing in our evening skies till they set in November at the 
 southwest. In Aquarius you will find that Zeta () the central star 
 of the little Y which marks the water-jar is a double, though rather 
 difficult; mags. 4.5 and 4.2. Gamma (y) in the small constellation 
 called Delphinus is more easily divided; mags. 5.4 and 4.4. 
 
 Among the most conspicuous landmarks of the sky is "the 
 Great Square of Pegasus," shown here and shown also in Map II. 
 It is made by three of the brighter stars of Pegasus in combination 
 with the Alpha (a) of Andromeda. It is at the east in the evening 
 skies of August, is directly above us in November, and sets at the 
 west in early February. The star Epsilon (e), magnitudes 2.5 and 
 8.5, is a double, but a little difficult. In the neighboring constella- 
 tion of Pisces or The Fishes, the stars Zeta (), magnitudes 5.5 and 
 6.4, and Psi (i//), magnitudes 5.5 and 5.8, are easier to divide. 
 
 Starting at one of the northern corners of the Square of Pe- 
 gasus, from the star Alpha (a) of Andromeda, let us now follow 
 the line which leads through the latter constellation. We shall 
 find here the easy doubles Pi (?r), magnitudes 4.5 and 8; and 56, 
 magnitudes 5.8 and 6.0; and at the position indicated by the little 
 triangle near the small star Nu (i/) we shall be able to distinguish 
 Andromeda's great nebula. Use your eye-piece of lowest power, 
 
 19 
 
for you will want a large field. Choose a night clear, but not 
 flooded by the moonlight, for you will want the benefit of contrast. 
 This nebula is the largest of the spiral type, its diameter having 
 been estimated as 500,000 times the distance between the earth 
 and the sun, "light requiring eight years to travel across it." It is 
 decidedly oval in shape, brighter at its center than at its edges. 
 In a small instrument it is not so impressive to a beginner as is a 
 cluster, like the Pleiades ; but in its own way, in the far reaches of 
 its faint luminous glow, it is, to the discriminating observer, quite 
 as interesting. 
 
 The Planets 
 
 The planets are of our own family, and revolve 
 with our little earth about the sun. They are not 
 1909 themselves great self-luminous suns, as are the 
 "fixed stars" we have thus far studied. Because the 
 i9ii planets are thus near, and because they chiefly shine 
 by reflected light, they show an appreciable disc, or 
 1913 surface outline, within the telescope, though only 
 Venus, Jupiter and Saturn are of special interest in 
 a small instrument. Mars, indeed, is worth observ- 
 ing, for his ruddy glow and perhaps one of his more 
 conspicuous markings, but the much-discussed "canals" are for 
 larger glasses. Saturn, however, even in a small instrument, is an 
 object of surpassing interest. 
 
 You can easily identify Saturn by the steadiness of its yellow 
 light. Your 25 x eye-piece will distinctly show the existence of the 
 ring formation, but you can here use the 50 x with greater advan- 
 tage. With the higher power you will see the chief peculiarity of 
 the planet more clearly, though not on so large a scale as in our 
 little cut, and you will also see Titan, the largest of the nine satel- 
 lites. But Saturn's chief attraction is shown in our illustration, a 
 phenomenon unique so far as our knowledge goes in the whole 
 range of our universe. Because of the changes in the relative posi- 
 tions of the planets in reference to each other, the rings of Saturn 
 are sometimes turned "edge on" toward the earth and are then 
 difficult to see. This was the case in 1907, as shown in the first 
 figure of our little illustration. But through 1909 and 1910 the 
 rings gradually open out, permitting a more satisfactory telescopic 
 view. They are composed of "swarms of meteors" in revolution 
 about the planet as a center. The extreme diameter at the outer 
 edge is more than 172,000 miles. 
 
 20 
 
Venus, so splendidly beautiful to the unaided eye, has no satel- 
 lite to interest us and no marked peculiarity of form. These facts, 
 together with its excessive brilliance in a glass, make it a disap- 
 pointing telescopic object. Most interesting, however, is the ob- 
 servation of the planet when she assumes her crescent phase, for 
 there are periods of the year when she puts on this aspect of the 
 new moon. It is an aspect of her charm which will be presented 
 when she shines at her brightest in the west during the evenings 
 of January, 1910, and in the east during the mornings of March 
 and April, 1910. 
 
 Jupiter and his satellites will form a delightful and inexhausti- 
 ble source of interest and pleasure. Even with the 25 x eye-piece 
 four of the eight moons are distinctly visible in our little instru- 
 ment, and the field of view is so large and so well lighted that the 
 spectacle is peculiarly satisfying. With the 50 x eye-piece they are 
 brought out even more vividly ; and by a good eye, under favorable 
 conditions, the cloud-belts across the body of the great planet may 
 be discerned. The movement of the satellites is so rapid, as they 
 revolve in their orbits, that we can see them change their relative 
 positions almost from hour to hour; one night three will be upon 
 one side the planet, one upon the other; the next night there will 
 be two on either side; and, yet again, as the satellites are hidden 
 by the body of the planet, or are eclipsed, or are in transit across 
 his huge disc, one or more of them will be wholly hid from view. 
 
 References to familiar sources of information for the easy find- 
 ing of the planets, together with other inexpensive literature con- 
 cerning their nature and their movements are given in note 10, 
 paragraphs 2 and 4, p. 38. 
 
 21 
 
OF THE 
 
 UNIVERSITY 
 
Part II. 
 
 The Moon 
 
 
The Moon 
 Some Interesting Lunar Objects 
 
 The user of our Prism Terrestrial Telescope will find especial 
 pleasure in the observation of the moon. Not only does the ex- 
 cellent definition of the instrument show the lunar topography with 
 remarkable clearness and fullness of detail, but the very fact that 
 a terrestrial telescope does not invert the image as is the case 
 with astronomical telescopes is of much satisfaction to a begin- 
 ner. Our halftone engravings and our miniature key-map are pre- 
 sented, therefore, "right-side-up," in harmony with the view as 
 observed in a terrestrial instrument and in conformity with the 
 natural expectations of the eye. 
 
 As you look at our first photograph of the moon you will see 
 that the objects on its surface are made distinct to us by the lunar 
 shadows. As the sunshine dawns or dies away over plains and 
 mountains, the objects near the edges of the advancing or receding 
 light are brought into sharp relief. In the direct illumination which 
 obtains when the moon is "full," we can see little detail, for shad- 
 ows are then largely absent. Looking at each of our photographs 
 in turn, you will now be able at once to understand why the same 
 object such as Copernicus, the huge crater-mountain marked No. 
 28 in our key-map should present so different an aspect at differ- 
 ent times. These ceaseless changes caused by the different angles 
 at which the sun's light strikes the surface make one of the chief 
 fascinations of lunar study. 
 
 But in order to show clearly all of the chief objects on the 
 moon by the photographic process, we should thus have to present 
 dozens of pictures instead of two. These two, however, are enough 
 to explain the constant changes of illumination and to illustrate 
 the value of our little key-map. Without the key-map and this 
 accompanying explanation you might possibly infer from the pho- 
 tographs themselves that the objects lying outside the shadows in 
 the darkness, or in the confusion of the direct light are always 
 hidden from observation. On the contrary, the region of the moon 
 toward the reader's right, which seems obscured in the moon at 
 nine and three-quarter days by the direct glare (the objects num- 
 bered 1, 2, 3, 4 in the key-map) are as clear when the moon is 
 younger (two to four days old) as is Copernicus (No. 28) in our 
 first engraving. 
 
 25 
 
The Moon at Nine and Three-quarter Days 
 
 With the moon, as with the stars, do not assume as beginners 
 are so apt to do that the more powerful eye-piece is necessarily 
 the first that should be employed. As the lower powers always 
 afford a much larger field of vision, it is always well to use the 25 x 
 in locating the object in the telescope. Then the 50 x eye-piece 
 may be substituted. If there is haze or mist, the lower power may 
 well be retained; if the atmospheric conditions are good, you will 
 of course gain with your higher power a greater fullness of detail 
 and much larger magnification. 
 
 Early in our study of the moon let us mentally mark and note 
 the general position of some of the greater "seas," not seas in fact, 
 but dark plains upon the lunar surface. Their quaint names were 
 given them many generations ago. That marked No. 1 was named 
 
 26 
 
,fe/\ 
 
 (*K ) 
 
 "The Sea of Crises," or "The Sea of Conflicts." We roughly trans- 
 late the Latin titles. That marked No. 5 is the Sea of Fecundity; 
 No. 6 is the Sea of Nectar; No. 7 is the Sea of Tranquility; No. 8 
 is the Sea of Serenity; No. 21 is the Sea of Showers. 
 
 The Sea of Conflicts, No. 1, seems to be longer from north to 
 south (up and down) than from east to west. This, however, is 
 an optical illusion, due to foreshortening; its width, from north to 
 south, being about 280 miles, and the distance from its eastern to 
 its western boundary being over 350 miles. Two craters may be 
 
 readily discerned within it the lower 
 having the name Picard, the upper be- 
 ing called Peirce. These are so small 
 that while they may be readily seen with 
 the telescope when the Moon is about 
 (V?\ four days old, they are not indicated in 
 ^ the key-map. No. 1 and its neighboring 
 objects as already stated are seen in 
 clear and beautiful detail in the very 
 new moon. This great oval plain com- 
 prises about 66,000 square miles. Just 
 Key Map above it, marked No. 2 in the key-map, 
 
 is Cleomedes, a smaller formation, a walled plain 78 miles in 
 diameter. A little way below No. 1 is the crater Langrenus, No. 3, 
 with its terraced ring over 9,500 feet high. The next crater except 
 one which we do not mark is Petavius, No. 4, the eastern side of 
 its great double rampart being 11,000 feet in height. All these 
 objects, as has been said, are too directly lighted to be well seen 
 under the illumination of the nine or ten day moon, so they appear 
 only as bright patches in our first photograph. 
 
 In the objects numbered 10, 11, 12 we again find almost 
 "drowned in light," three peculiarly interesting craters which in 
 the younger moon at about six days old are superbly clear. In 
 this particular case, however, we find recompense in our second 
 photograph. For, ten days later, in the receding light of the sun, 
 these objects Theophilus, Cyrillus and Catharina are again de- 
 fined in the lines of grateful shadow. 
 
 Theophilus, No. 10, is probably the deepest of the moon's 
 craters, the general line of the ring being from 14,000 to 18,000 feet 
 above the chasm. Of this triple group, it "first catches," says 
 Webb, "the rising sun, and I have seen it far beyond the ter- 
 minator (the shadow line) and even without the telescope, five 
 days after new ; it is a grand object when filled with night, through 
 which its glittering central peak comes out like a star." In our 
 
 27 
 
The Moon at Eighteen and a Half Days 
 
 second photograph, in the now retreating shadows of the sun, you 
 can clearly see the bright cap of this central peak. 
 
 Cyrillus, No. 11, is even larger; and Catharina, No. 12, is 
 perhaps the largest of the three, irregular in character but more 
 than 16,000 feet deep. As with all the objects of our study these 
 craters should be observed under different illuminations. If pos- 
 sible, it is well to make two observations on the same evening 
 one at an early hour and another somewhat later. And in using 
 the little key-map, each object specified should be examined with 
 the aid of both our photographs. 
 
 As our little telescope will clearly show more than three hun- 
 dred objects upon the moon's surface each having its own distinct 
 
 28 
 
and proper name it is obviously impossible here to indicate them 
 all. And upon the beginner the effect of so much detail would be 
 confusion and discouragement rather than information and pleas- 
 ure. We confine ourselves to approximately forty objects. Even 
 this number will seem bewildering to the novice. We suggest, 
 therefore, that for the first few evenings of his observation he 
 rigorously confine himself to four or five. Let him get these well 
 in mind. Then, with these as landmarks, he will be surprised and 
 delighted to see how rapidly his information will advance. 
 
 We have already spoken of the 
 objects 10, 11, 12 conspicuously 
 lighted in our second photograph as 
 well as in the six and seven-day moon. 
 In the nine-day moon we shall find an- 
 other triple group (23, 24, 25 in the 
 key-map) called Ptolemy, Alphonsus, 
 and Arzachel. This group is shown in 
 both our photographs. Quite near the 
 edge of Alphonsus you will observe 
 the smaller crater called Alpetragius 
 
 Miniature Key Map Qne o f the deepest On the mOOn. To 
 
 the right, No. 26, is Albategnius. One cannot but feel a strong 
 desire to change some of these formidable names! 
 
 We have hastened to speak of the triple group 23, 24, 25 chiefly 
 to prevent its confusion with 10, 11, 12. We will now return to 
 some of the earlier numbers. In No. 9 of our key-map we again 
 have an object shown in our photographs under two different light- 
 ings. This is Posodonius, a walled plain about 62 miles across, 
 containing a small but sometimes brilliant crater. No. 18 is 
 Manilius, and to its right is Pliny. The former is over 7,500 feet 
 deep and about 25 miles in diameter. No. 13 is Aristotle, No. 14 
 is Eudoxus ; a superb pair of craters, the terraced wall of the former, 
 over 11,000 feet high, being crowned by two turrets of 15,000 feet. 
 In this great cavity, says one authority, the Mount Etna of our 
 earth could stand. No. 19 is Cassini, a ring-plain with a small 
 deep crater. No. 20 is Plato, well shown in both our photographs, a 
 great ring-plain 60 miles across. Above Plato lies the Sea of Cold; 
 below Plato is the Sea of Showers, and within the latter we have 
 marked for special consideration the objects numbered 15, 16 and 
 17, Archimedes, Autolycus, and Aristillus. The range of moun- 
 tains terminating at Eratosthenes (No. 22) is known as the Apen- 
 nines, a chain somewhat like the mountains of the earth. Its length 
 is 460 miles. To the left of No. 22 lie the Carpathian Mountains, 
 and in No. 28 we have one of the most superb of lunar spectacles, 
 
 29 
 
the huge crater Copernicus, 56 miles in diameter. It is the center, 
 as may be seen in our second photograph, of one of those systems of 
 light radiation which form one of the most striking features of the 
 moon's aspect. Another center of these radiations, as you will see, 
 is Kepler, No. 36. No. 27, Aristarchus, is usually regarded as the 
 most brilliant single point upon the moon. No. 34, Grimaldi, is by 
 contrast the darkest of the lunar craters. 
 
 In No. 29, seen far better in our first photograph than in our 
 second, we have Bullialdus, a great crater, 9,000 feet deep and 38 
 miles across. No. 35 is Rheinholdt. We turn now, however, to the 
 southern or lower quarter of the moon's surface in order that we 
 may close our brief descriptions with a word concerning a few of 
 the objects in the neighborhood of No. 30, Tycho, "the metropolitan 
 crater." The whole region is one of mighty cataclysm, of appalling 
 heights and depths. Longomontanus, No. 31, is apparently one of 
 the oldest of volcanic formations, its great walls having been rent 
 and shattered by recurrent explosions. Maginus, No. 32, is one 
 of a number of lunar objects which, while presenting a superb spec- 
 tacle under certain phases of illumination, are entirely invisible at 
 full moon. Clavius, No. 33, is especially interesting by reason of 
 the craters within its limits; their shadows are finely outlined in 
 the lunar sunrise. This, and many objects which must necessarily 
 be omitted from a list as brief as the present one, may be further 
 studied in some of the publications cited in par. 10, p. 38. 
 
 The great crater Tycho, No. 30, is not only of unique interest 
 in itself, but is the central point for the most splendid system of 
 radiations on the moon. In both our photographs the reader can 
 partially see the spreading of these lines of light. So brilliant do 
 they become when the moon is full that this huge crater dominates 
 the scene, the light-streaks extending from it in all directions. 
 Webb calls Tycho "a most perfect specimen of the lunar volcano, 
 roughly figured by Galileo in the earliest telescopic representations. 
 Its diameter is 54 miles, its depth 17,000 feet or nearly three miles, 
 so that the summit of our Mont Blanc would drop beneath the 
 ring. Its vicinity is thronged with hillocks and small craters so 
 that for a long distance not the smallest level spot can be found; 
 further off the craters increase till the whole surface of the region 
 resembles a colossal honeycomb." 
 
 "There are," says Noble, in his "Hours With a Three-inch 
 Telescope," "few more curious, instructive, nay even startling 
 sights in the heavens than the occultation of a fixed star, or 
 
 30 
 
more rarely of a planet, by the moon. When this occurs at the 
 dark limb of our satellite, its suddenness is such as not infrequently 
 to extort an exclamation from the observer who witnesses it for 
 the first time. . . In describing her monthly path over the 
 celestial vault, it is quite obvious that the moon must pass be- 
 tween us and such stars as lie in her course ; the stars being 
 for our present purpose at an infinite distance, while she is only 
 some 239,000 miles from us. . . Travelling thus, as I have said, 
 from west to east, her eastern limb is, of course, the leading one, 
 or that which covers, hides, or occults objects lying in her path. 
 From new moon to full moon this limb is unilluminated, and the 
 effect of the extremely sudden extinction of a star when the dark 
 limb hides it is, as I began by saying, of an absolutely startling 
 character. 'In a moment, in the twinkling of an eye,' the star 
 which shone as a brilliant point in the sky is blotted out; and its 
 place seemingly knows it no more, until it reappears from behind 
 the opposite or illuminated edge of the moon. After full moon, 
 of course, the eastern limb is illuminated, so that the disappearance 
 takes place at the bright edge, and the star on its reappearance 
 starts instantaneously from behind the dark limb." The more 
 interesting occultations are fully predicted and enumerated in the 
 Whitaker's almanac mentioned in the closing paragraph of note 10, 
 page 38. 
 
 In addition to the literature concerning the moon, as mentioned 
 in note 10, page 38, we also refer to "The Moon in Modern Astron- 
 omy" by Philip Fauth, with an introduction by J. Ellard Gore, 
 F. R. A. S. ; published by the Van Nostrand Co., New York. With- 
 out endorsing, necessarily, some of the theoretic contributions of 
 the volume we are sure the amateur astronomer will find much 
 pleasure in its illustrative and descriptive matter. 
 
 31 
 
Part III. 
 
 Notes and Suggestions 
 
Notes and Suggestions 
 
 1. Readers of this booklet are advised before beginning the 
 specific use of any particular part of it to read it through as a 
 whole. The suggestions made at one point will often prove helpful 
 in other connections. 
 
 2. Our half-tone engravings of the moon are reduced from 
 direct contact prints of negatives made with the great 40-inch 
 Yerkes telescope, designed and constructed by The Warner & 
 Swasey Company for the University of Chicago at Williams Bay, 
 Wisconsin. As all photographs taken with an astronomical tele- 
 scope show the object inverted in the field of view, the above prints 
 are presented "erect" in this booklet, in conformity with the re- 
 quirements of a terrestrial instrument. 
 
 3. The user of a camera expects to make a few failures before 
 getting the best results, the user of any form of mechanical equip- 
 ment whether it be the bicycle, the automobile or even a pair of 
 roller skates expects to put a little thought and care into the 
 mastery of the machine. It is so with a telescope. While far 
 simpler than the "modern creations" which we have mentioned, the 
 beginner should not begrudge the expenditure of a little thought 
 and time if he would gain intelligent command of the instrument 
 itself and of the resources which it will bring him. 
 
 4. It is to aid the beginner in one department of its use that 
 this booklet has been prepared. Yet it is not intended as a library 
 on astronomy or as a complete telescopic manual. The little maps 
 are necessarily inadequate and are not presented as a substitute for 
 such a "star atlas" as the advanced amateur will desire. In maps 
 so small many stars must necessarily be omitted; other and per- 
 haps smaller stars because of some special telescopic interest, or 
 because of their connection with the constellation figures have 
 been included. The diagrams are offered just as rough approximate 
 guide-maps for elementary telescopic work. 
 
 5. While our references to particular stars are so clearly given 
 as not to necessitate the memorizing of the Greek alphabet, that 
 alphabet is here printed as a matter of convenience to the beginner. 
 A general familiarity with the characters is easily acquired and 
 indispensable in the use of larger star-maps: Alpha, a; Beta, /?; 
 Gamma, y ; Delta, 8; Epsilon, ; Zeta, ; Eta, ??; Theta, 0; 
 Iota, t ; Kappa, K; Lambda, A; Mu, /*; Nu, v; Xi, ; Omicron, o; 
 Pi, TT ; Rho, P ; Sigma, o- ; Tau, r ; Upsilon, v ; Phi, <f> ; Chi, x ; Psi, \j/ ; 
 Omega, o>. 
 
 35 
 
6. As already suggested on p. 12, the use of a plain straight- 
 back chair, without arms, will be of much service to the observer 
 employing so light an instrument. As he takes his place in the 
 chair the instrument may be drawn toward him, and sitting al- 
 most directly beneath the tripod, a leg of the tripod falling naturally 
 into position at each side of him he will be able with very little 
 adjustment of the telescope to command almost any altitude. Stars 
 obscured by mists at the horizon or inconveniently high up may be 
 permitted to wait the observation of those at better range. If the 
 beginner will early learn to take what Fortune brings, he will 
 always find that Fortune, whatever her negligences, will surely 
 bring the stars again. At a later hour on the same evening, or at 
 the same hour on a later evening, he will be rewarded. 
 
 7. Among the interesting astronomical phenomena of 1909- 
 1910 is the return of Halley's comet, after an absence of nearly 76 
 years. The comet in October, 1909, will be not far from the little 
 star marked Nu (v) in Orion (Map II). You will see this star 
 just above the bright star Betelgeuse, and a little to the left. Pass- 
 ing westward through the constellation Taurus the comet will 
 move along the southern part of the constellation Aries, and from 
 thence as we watch it from week to week we shall see it pass 
 into the region of Pisces, the Fishes. A telescope will probably be 
 needed for its observation during the autumn of 1909, but by the 
 early spring of 1910 it is likely to be a conspicuous object even to 
 the unaided eye. Its visible advance into our skies will, of course, 
 be first heralded by those commanding larger instruments ; the pos- 
 sessor of our two-inch terrestrial will thereafter find much interest 
 in observing its first appearance and its gradual brightening under 
 the modest powers of his own telescope. 
 
 8. Some one has well said that "the most important part of 
 a telescope is the man at the small end of it." This is but a recog- 
 nition of the fact that there is such a thing as a trained eye as well 
 as a trained hand or a trained will. The beginner may be sure, 
 therefore, that as he extends his familiarity with his instrument 
 and as he gains in clearness and accuracy of vision, his telescope 
 will be an increasing satisfaction. Two of the personal conditions 
 of good-seeing may be especially commended: Work in comfort, 
 and work with deliberation. Holding the telescope in trying posi- 
 tions, getting the head or body into fatiguing or unnatural attitudes, 
 are directly embarrassing to clear, accurate seeing. And because 
 we thus see with the mind as well as with the eye, much of the 
 reward of exquisite vision is found in deliberation. Do not rush 
 from star to star. In looking, for example, at a beautiful double 
 star like the Gamma (y) in Andromeda see p. 14 quiet, thought- 
 ful observation, after you have secured a sharp focus, will add much 
 to your real pleasure in what you see. In this case, you are looking 
 at two splendid suns thousands of millions of miles distant from 
 our earth, so different in their chemical constitution that their con- 
 trasted colors are at least partially conveyed to us through all the 
 intervening space. 
 
 9. In our little map at the top of p. 12 the Dipper is shown 
 in its approximate position for the early evening of May 1st. As 
 
 36 
 
it turns westward (to the observer's left), the two stars marked 
 "The Pointers" (no matter what the position of the Dipper), will 
 always indicate the direction of the bright star, Polaris, or the 
 Pole Star, which lies nearest to the polar "hub." All the stars in 
 our little map, ever keeping the same permanent relations to each 
 other as though fixed on the respective spokes of a great wheel 
 revolve also, as does the Dipper; but Polaris lies so near the pole 
 of the heavens that its motion is almost unappreciable ; it seems to 
 the "wayfaring man" to stand ever fixed at the true north. It is 
 also, as you can see, the leading star in the "Little Dipper," part 
 of the constellation called "Ursa Minor." 
 
 Still looking at our first map, you will see that the further a 
 star is from the pole the larger must be the circle it describes, as 
 the great wheel revolves ; and that the stars located further out on 
 its spokes (to continue our figure) will, with the wheel's turning, 
 dip below the horizon for a shorter or longer period. Those, how- 
 ever, that lie within about forty degrees of the pole are never 
 carried quite out of the sight of observers in the latitude of Cleve- 
 land and New York; they are called the stars of the "circumpolar 
 constellations." These are roughly indicated in Map I, and are 
 always in our night sky. 
 
 The stars that are further from the pole are indicated in Maps 
 II, III, and IV. They pass out of our night skies for shorter or 
 longer periods of time ; and as we come to study them we shall see 
 that our figure of speech must be changed. For, as we look toward 
 the true north, we are gazing not strictly at the hub of a flat wheel, 
 but toward the pole of a hollow sphere, its apparent axis the pro- 
 jection of the earth's axis, and its equator the projection of our 
 own equator. We may imagine the spokes of the revolving wheel 
 as they extend gradually bending inward toward us, and forming 
 the ribs of a vast including globe. We stand enclosed as it were 
 at the sphere's center. 
 
 The circumpolar stars turn with the sphere itself, but as they 
 lie so near its pole, the circle of their revolution never carries them 
 below our horizon. Sometimes, for example, we see the Dipper 
 above the North Star, sometimes below it; sometimes it is a little 
 to our left, the bowl slowly turning downward, sometimes it is 
 toward the right with the bowl climbing upward, but it is always 
 in our northern sky. Yet, with the sphere's turning, the stars 
 further from the pole (Maps II, III, IV), like bright points fixed 
 on the inner surface of its concave sides as these arch themselves 
 above and below the horizon appear and disappear according to 
 their hours and their seasons. A few minutes of actual observa- 
 tion for a couple of evenings will make this subject clear, even to 
 children of grammar-school grades. An admirable and much fuller 
 exposition of the diurnal motion of the stars will be found in 
 Newcomb's volume, mentioned on p. 38. 
 
 10. The beginner may wish to supply himself with a few 
 volumes that will help to enlarge his knowledge. First, he will 
 enjoy gaining some measure of familiarity with the chief constella- 
 tions. Among the best helps here are Olcott's "Field Book of the 
 
 37 
 
Stars," published by Putnam's, New York; and Serviss's "Astron- 
 omy with an Opera Glass," published by D. Appleton & Co. A 
 Planisphere will be found a most useful device for ascertaining the 
 positions of the stars from night to night. An inexpensive one is 
 sold by Thomas Whittaker, 2 Bible House, New York. As a 
 substitute, readers of French may prefer to use one upon the same 
 plan as Whittaker's, called the "Carte Celeste," published by Burk- 
 hardt, 2 Place du Molard a Geneve, to be had through any of 
 Brentano's book-stores. 
 
 Readers of German will find attractive star maps and ex- 
 cellent descriptive matter in the Stern-Atlas of Jacob Messer. The 
 "Himmel Atlas" of Schurig is less expensive and the new edition 
 is extremely useful even to those who do not read German. Both 
 volumes may be had of G. Steckert, 129 W. 20th St., New York. 
 Among English atlases may be mentioned "The New Star Atlas," 
 by Proctor, published by Longmans, Green & Co. ; and Sir Robert 
 Ball's "Popular Guide to the Heavens," published in New York 
 at $4.50, by Van Nostrand. The latter contains not only a star 
 atlas, but charts showing the position of the stars from month 
 to month, simple tables for finding the planets, photographs of 
 clusters and nebulae, and admirable maps of the moon, etc. 
 
 Among the many interesting books upon the general principles 
 and facts of astronomy, we may mention S. P. Newcomb's "Popular 
 Astronomy," published by the American Book Co. It is especially 
 clear and able in its expositions. Among other admirable text-books 
 may be mentioned those by Todd, Young, and Moulton. Our little 
 cut of Saturn on p. 20 is drawn from a portion of a cut in Prof. 
 Todd's "New Astronomy," the American Book Co., New York. In 
 the use of the telescope, whether in observing the moon or the stars, 
 the advanced amateur will want some such volume as "Webb's 
 Celestial Objects for Common Telescopes," 2 vols., $1.75 each; 
 London and New York, Longmans, Green & Co. Much of it will 
 be too advanced for the beginner, but even very early in his work 
 he will find a great deal in it to give him pleasure. Among 
 more popular books, Noble's "Hours With a Three-inch Telescope" 
 (Longmans, Green & Co.) is especially useful and interesting for 
 its chapters on the moon. 
 
 In following the course of the planets the beginner will find a 
 good almanac almost indispensable. The astronomical matter pub- 
 lished in the New York Tribune almanac and in the almanac of the 
 Brooklyn Eagle usually presents a simple table showing in which 
 constellation each planet may be found from week to week through- 
 out the year. The best almanac, however, for the amateur astron- 
 omer is undoubtedly the English "Whitaker's," published at 12 
 Warwick Lane, London not to be confused with the American 
 house publishing the planisphere. This almanac may be secured 
 through any large bookseller. Its tables of the interesting as- 
 tronomical phenomena for each month are especially full and 
 valuable ; and the movements of the planets and the configurations 
 of the satellites of Jupiter, etc., are presented with simplicity and 
 
 38 
 
clearness. "Whitakers" may be had in several editions, ranging 
 from about 30c to $1.00 in cost. 
 
 11. After the beginner has become familiar with his instru- 
 ment and with the telescopic objects already mentioned, he may 
 find it interesting to try some additional double stars. The follow- 
 ing list is, of course, not complete, and of the objects enumerated 
 some are easy and others are more difficult. If you do not succeed 
 with a specific star on one evening, try it on another. Changes in 
 atmospheric conditions are more frequent and more important than 
 many amateurs realize. In Map I, try in the constellation Draco 
 the star Psi, \j/ (mags. 4.9 and 6.0) ; and the star Omicron, o 
 (mags. 4.8 and 7.6). In Cassiopeia, try Iota i (mags. 4.8 and 8.1). 
 In Perseus, note Eta (>?), mags. 3.9 and 8.5. In Ursa Minor, the 
 star Pi, -a (mags. 6.9 and 7.6) ; in Cepheus, Beta, /? (mags. 3.5 and 
 8.0). In this constellation, the star Mu, /x, while not a double is 
 one of the most famous of the red stars called by Herschel a "gar- 
 net." In Map II, try in Auriga the star 14, mags. 5.1 and 7.2; in 
 Aries you will find easy doubles, both in Lambda, A (mags. 4.8 and 
 8.0); and Gamma, y (mags. 4.8 and 4.7). Note the Lambda, A, in 
 Orion (mags. 3.6 and 5.5). In Eridanus, try the stars marked 6 
 (mags. 5.7 and 8.0), 55 (mags. 6.0 and 7.1), and 32 (mags. 4.8 and 
 6.4); and in Cancer, the star Zeta, (mags. 4.8 and 6.5). In this 
 case as well as in a few others, the star appearing as a double in a 
 small telescope is really a triple or a multiple as viewed in a larger 
 instrument. It may also be interesting to note two of the im- 
 portant "variables" shown in Map II. We have already spoken 
 of the star in Perseus marked Beta, /?. The regular variations in 
 the brilliancy of its light are so remarkable that the Arabs called 
 it "Algol," the Demon. At minimum it sinks to fourth magnitude, 
 but it so remains only about 15 minutes, when, within 5y 2 hours, 
 it becomes again a second-magnitude star. Another remarkable 
 variable in our map is Mira, in the constellation Cetus, the Whale. 
 Its "period" is longer, being over 331 days, but it varies regularly 
 from absolute invisibility, for the naked eye, to a star of the 
 second magnitude! Toward the bottom of Map IV, at the right, 
 you will note the Alpha (a) and Beta (/3) of Sagittarius, the Archer. 
 The star /?', if you are living far enough south to command a view 
 of it, is an interesting and easy double (mags. 4.2 and 7.2). 
 
 12. The beginner, in noting the little table of symbols (Map I), 
 will see that the smaller the value of the numeral the higher the 
 magnitude of the star. A first magnitude star is a very bright one, 
 an eighth magnitude star is a very faint one. Little attempt has 
 been made in the maps themselves to secure absolute accuracy as 
 to these magnitudes the drawings are necessarily too small for 
 the varied use of many different symbols. But in the text of our 
 descriptive matter the magnitudes of the components of the double 
 stars are given according to the revised Harvard Photometry for 
 1908; or, in the cases of a few small components not included in 
 that list, according to the "Sternverzeichnis" of Ambronn, Univer- 
 sity of Gottingen, 1907. The "magnitude" of a star has no neces- 
 sary relation to its actual size ; the term refers solely to its apparent 
 brightness as seen from our earth itself. Many of the fainter stars 
 
 39 
 
may be actually larger and more luminous than those we classify as 
 first magnitudes, their apparent faintness, in such cases, being due 
 only to their greater distance. 
 
 13. This factor of distance in the observation of the stars is so 
 great that it wholly transcends all our ordinary conceptions of 
 space. Yet a lack of knowledge upon this point is the occasion 
 among beginners of much disappointment in the first using of a 
 telescope. Do not expect your telescope, however large in size 
 or fine in quality, to lend a large surface image or a broad sensible 
 disc to any of the "fixed stars." 
 
 With the moon and with the planets, as we have seen, things 
 are slightly different: these are relatively very much nearer to the 
 earth. But so remote are the hosts of the stars proper (the very 
 nearest being over twenty-five millions of millions of miles distant) 
 that no telescope, however great, will ever make them in the popu- 
 lar sense any "bigger." The highest power usually provided with 
 our little instrument is 50 diameters. Let us suppose, however, 
 that we were able to use a telescope affording us a magnifica- 
 tion of 5,000 diameters. As such a power would magnify all 
 the conditions of atmospheric obscurity or disturbance (as well 
 as the star) there are few of us who could get any satisfaction 
 from it. But on the assumption that we could use it under 
 fine atmospheric conditions what would it mean to us? It would 
 bring a star that might be 50,000 million miles from us to a distance 
 of 1,000 million miles! That is not very near, is it? But there is no 
 star so near as 50,000 million miles: nor any so near as 500,000 
 million miles. The very nearest, as we have said, is 25,000,000 mil- 
 lion miles away and no star even so near as that is visible to us 
 north of our tropic latitudes. 
 
 Astronomers, accordingly, ignore the mile as a unit of measure. 
 Their unit is the light-year, the distance traversed by light speed- 
 ing at 186,330 miles a second in a year of time. Our North star, 
 for example, is at a light distance of 40 years that is to say the 
 light by which the mariner may now take his reckoning (1909) 
 was started on its way toward us in 1869. As you bear these dis- 
 tances in mind you will not find fault with your little telescope if 
 it does not make a star assume the proportions of a dinner-plate. 
 But if you will employ your instrument under some of the simple 
 instructions of the preceding pages, you will find that it will give 
 you results even more interesting than the mere enlargement of 
 size. 
 
 40 
 
Specifications 
 
 Objective clear aperture 
 
 Powers two eye-pieces 
 
 Length of telescope 
 
 Weight of telescope 
 
 Weight of tripod and alt -azimuth mounting 
 
 Weight, complete with carrying case 
 
 Dimensions of carrying case 
 
 2 inches 
 
 25 and 50 
 
 . 21^ inches 
 
 2}^ Ibs. 
 
 4 Ibs. 
 
 12 Ibs. 
 
 12x6^x4^ inches 
 
 41 
 
THE WARNER & SWASEY 
 
 PRISM 
 
 TERRESTRIAL 
 TELESCOPE 
 
 The Warner & Swasey Company 
 
 Cleveland, Ohio, U. S. A. 
 
 Circular .4-251909 
 
SPECIFICATIONS 
 
 Objective clear aperture 2 inches 
 
 Powers two eye-pieces 25 and 50 
 
 Length of telescope 21 ^ inches 
 
 Weight of telescope 2^ Iks. 
 
 Weight of tripod and alt-azimuth mounting 4 Ibs. 
 
 Weight, complete with carrying case 1 2 Ibs. 
 
 Dimensions of carrying case - 24x6>4 x4^ inches 
 
THE WARNER & SWASEY PRISM 
 TERRESTRIAL TELESCOPE 
 
 T 
 
 'HE 2-inch Porro Prism Tele- 
 scope is designed expressly for use 
 as a terrestrial instrument. Its large 
 field, high magnification and superior 
 construction represent the highest de- 
 velopment in terrestrial telescopes. As an example of 
 its excellence, it will show clearly so delicate an object as 
 the moving second hand of a watch at a distance of 300 
 feet. At from five to seven miles, in good atmospheric 
 conditions, it will reveal the time of day by the town 
 clock in the old meeting house tower, while at ten miles 
 or more what appeared as mere specks are sharply 
 brought out as recognizable objects ; that white dot is a 
 quarry of building stone, not a house. In other words, 
 the 2 5 -power eyepiece brings the object apparently twen- 
 ty-five times nearer and the 50-power eyepiece fifty 
 times nearer. Of course, atmospheric conditions modify 
 the " seeing." On a clear day, with no wind, an object 
 can be seen farther and better than in hazy weather, but 
 under any conditions The Warner & Swasey Prism Ter- 
 restrial Telescope enables the user to see more and better 
 and farther. It is the ideal instrument for terrestrial use. 
 
THE WARNER & SWASEY PRISM TERRESTRIAL TELESCOPE 
 
 Complete with 
 
 ALT-AZIMUTH MOUNTING, FOLDING TRIPOD 
 AND CARRYING CASE 
 
HOME USE 
 
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