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University of Illinois Library | OCT 23 1953 NAY 6 1954 L161—H41 ASTRONOMY WITH AN OPERA-GLASS A POPULAR INTRODUCTION TO THE STUDY OF THE STARRY HEAVENS WITH THE SIMPLEST OF OPTICAL INSTRUMENTS WITH MAPS AND DIRECTIONS TO FACILITATE THE RECOGNITION OF THE CONSTELLATIONS AND THE PRINCIPAL STARS VISIBLE TO THE NAKED EYE BY GARRETT P. SERVISS “* Known are their laws ; in harmony unroll The nineteen-orbed cycles of the Moon. And all the signs through which Night whirls her car From belted Orion back to Orion and his dauntless Hound, And all Poseidon’s, all high Zeus’ stars Bear on their beams trne messages to man.”’ PostTE’s ARATUS. EIGHTH EDITION, WITH APPENDIX NEW YORK AND LONDON Dense VON SAND COME AN Y 1923 apex CopyricH, 1888, aoe poe, By D. APPLETON AND COMPANY. : ; se ; Pacis . oes 22 We 2 4 |Ve IL Que P Oui wT m4 oy ke S 2 (ad. — ASF ~ ——pnA~TrE, QTOKAWY Savi) iri" A ise Va 4 TO THE READER. In the pages that follow, the author has endeavored to encourage the study of the heavenly bodies by pointing out some of the interesting and marvelous phenomena of the uni- verse that are visible with little or no assistance from optical instruments, and indicating means of becoming acquainted with the constellations and the planets. Knowing that an opera-glass is capable of revealing some of the most beautiful sights in the starry dome, and believing that many persons would be glad to iearn the fact, he set to work with such an instrument and surveyed all the constellations visible in the latitude of New York, carefully noting everything that it seemed might interest amateur star-gazers. All the objects thus observed have not been included in this book, lest the multiplicity of details should deter or discourage the very readers for whom it was specially written. On the other hand, there is nothing described as visible with an opera-glass or a field-glass which the author has not seen with an instru- ment of that description, and which any person possessing eye- sight of average quality and a competent glass should not be able to discern. | But, in order to lend due interest to the subject, and place it before the reader in a proper light and true perspective, many facts have been stated concerning the objects described, the ascertainment of which has required the aid of powerful telescopes, and to observers with such instruments is reserved the noble pleasure of confirming with their own eyes those 538681 i¥ TO THE READER. wonderful discoveries which the looker with an opera-glass can not hope to behold unless, happily, he should be spurred on to the possession of a telescope. Yet even to glimpse dimly these distant wonders, knowing what a closer view would re- veal, is a source of no mean satisfaction, while the celestial phenomena that lie easily within reach of an opera-glass are sufficient to furnish delight and instruction for many an evening. ; It should be said that the division of the stars used in this book into the ‘‘Stars of Spring,” ‘‘Stars of Summer,” ‘‘ Stars of Autumn,” and ‘‘ Stars of Winter,” is purely arbitrary, and intended only to indicate the seasons when certain constella- tions are best situated for observation or most conspicuous. The greater part of the matter composing this volume ap- peared originally in a series of articles contributed by the au-— thor to ‘‘The Popular Science Monthly” in 1887~’88. The reception that those articles met with encouraged him to re- vise and enlarge them for publication in the more permanent form of a book. | G7 Brook.yn, N. Y., September, 1888. CONTENTS. PAGE PRYRODUCLION de gay. oe a ren yee ee ae Popular interest in the phenomena of the BEATERE The opera-glass as an instrument of observation for beginners in star- study. Testing an opera-glass. - CHAPTER I. THe STARS OF SPRING . : : : : > a : Sey Description of the ee sinaionge atten the Charioteer; Berenice’s Hair; Cancer, the Crab [the Manger]; Canis Minor, the Tener Dog; Cor- vus, the Crow; Crateris, the Cup; Gemini, the Twins; Hydra, the Water- Serpent; Leo, the Lion; Ursa Major, the Greater Bear [the Great Dipper]; Ursa Minor, the Lesser Bear [the Pole-Star]. A circular index-map, maps on a larger scale, of the constellations de- scribed, and pictures of remarkable objects. CHAPTER II. THE STARS OF SUMMER . : : - DO Description of the PA te en the Eagle; Bodtes, the Herds- man, or Bear-Diver; Canes Venatici, the Hunting-Dogs; Cygnus, the Swan [the Northern Cross]; Delphinus, the Dolphin; Draco, the Dragon; Hercules [the Great Sun-Swarm, 13 M]; Libra, the Balance; Lyra, the Harp; the Northern Crown; Ophiuchus et Serpens, the Serpent-bearer and the Serpent; Sagitta, the Arrow; Sagittarius, the Archer; Scorpio, the Scorpion; Sobieski’s Shield; Taurus Poniatowskii, Poniatowsky’s Bull; Virgo, the Virgin [the Field of the Nebule]; Vulpecula, the Little Fox. A circular index-map, maps, on a larger scale, of the constellations de- scribed, and pictures of remarkable objects. CHAPTER III. THE Srars oF AUTUMN , aati Sik Satake ay at ot OU Description of the Constellations—Andromeda [the Great Nebula]; _ Aquarius, the Water-Bearer; Aries, the Ram; Capricornus, the Goat; Cassiopeia; Cepheus; Cetus, the Whale [Mira, the wonderful eartle star]; Pegasus, the Winged Horse. vi CONTENTS. . . PAGE Perseus [ Algol, the Demon-Star]; Pisces, the Fishes; Piscis Australis, the Southern Fish; the Triangles. A circular index-map, maps on a larger scale, of the constellations de- scribed, and pictures of remarkable objects. CHAPTER IV. THE STARS OF WINTER . : : ees ; : ‘ ; . 89 Description of the Constellations—Argo, Jason’s Ship; Canis Major, the Great Dog [Sirius]; Eridanus, the river Po; Lepus, the Hare; Mo- - noceros, the Unicorn; Orion [the Great Nebula]; Taurus, the Bull [the Pleiades and Hyades]. A circular index-map, maps on a larger scale, of the constellations ae- scribed, and pictures of remarkable objects. CHAPTER V. 3 THE MOON, THE PLANETS, AND THE SUN. : : : : . 118 Description of lunar “seas,” mountains, and “craters,” with a map of the moon, and cuts showing its appearance with a field-glass. Opera-glass observation of—The sun (one cut), Mercury, Venus, Mars, Jupiter and his satellites (one cut), Saturn, Uranus (three cuts), ASTRONOMY WITH AN OPERA-GLASS. _INTRODUCTION. STAR-GAZING was never more popular than itis now. In every civilized country many excellent telescopes are owned and used, often to very good purpose, by persons who are not practical astronomers, but who wish to see for themselves the marvels of the sky, and who occasionally stumble upon something that is new even to professional star-gazers. Yet, notwithstanding this activity in the cultivation of astronomi- cal studies, it is probably safe to assert that hardly one per- son in a hundred knows the chief stars by name, or can even recognize the principal constellations, much less distinguish the planets from the fixed stars. And of course they know nothing of the intellectual pleasure that accompanies a knowledge of the stars. Modern astronomy is so rapidly and wonderfully linking the earth and the sun together, with all the orbs of space, in the bonds of close physical relation- ship, that a person of education and general intelligence can offer no valid excuse for not knowing where to look for Sirius or Aldebaran, or the Orion nebula, or the planet Jupiter. As Australia and New Zealand and the islands of the sea are made a part of the civilized world through the expanding influence of commerce and cultivation, so the suns and plan- ets around us are, in a certain sense, falling under the domin- ion of the restless and resistless mind of man. We have come to possess vested intellectual interests in Mars and Sat- urn, and in the sun and all his multitude of fellows, which nobody can afford to ignore. 2 ASTRONOMY WITH AN OPERA-GLASS. A singular proof of popwar ignorance of the starry heav- ens, aS well as of popular curiosity concerning any uncom- mon celestial phenomenon, is furnished by the curious no- tions prevailing about the planet Venus. When Venus began to attract general attention in the western sky in the early evenings of the spring of 1887, speculation quickly became rife about it, particularly on the great Brooklyn Bridge. As the planet hung dazzlingly bright over the New Jersey horizon, some people appeared to think it was the light of Liberty’s torch, mistaking the bronze goddess’s real flambeau for a part of the electric-light system of the metropolis. Finally (to judge from the letters written to the newspapers, and the questions asked of individuals sup- posed to know something about the secrets of the sky), the conviction seems to have become pretty widely distrib- uted that the strange light in the west was no less than an electrically illuminated balloon, nightly sent skyward by Mr. Edison, for no other conceivable reason than a wizardly desire to mystify his fellow-men. I have positive informa- tion that this ridiculous notion has been actually entertained by more than one person of intelligence. And as Venus glowed with increasing splendor in- the serene evenings of June, she continued to be mistaken for some petty arti- ficial light instead of the magnificent world that she was, sparkling out there in the sunshine like a globe of bur- nished silver. Yet Venus as an evening star is not so rare a phenomenon that people of intelligence should be surprised at it. Once in every 584 days she reappears at the same place in the sunset sky— ‘““Gem of the crimson-colored even 3 Companion of retiring day.” No eye can fail to note her, and as the nearest and most beautiful of the Earth’s sisters it would seem that every- body should be as familiar with her appearance as with the INTRODUCTION. 3 face of a friend. But the popular ignorance of Venus, and the other members of the planetary family to which our mother, the Earth, belongs, is only an index of the denser ignorance concerning the stars—the brothers of our great father, the Sun. I believe this ignorance is largely due to mere indifference, which, in its turn, arises from a false and pedantic method of presenting astronomy as a creature of mathematical formule, and a humble handmaiden of the art of navigation. I do not, of course, mean to cast doubt upon the scientific value of technical work in astronomy. The science could -not exist without it. Those who have made the spectroscope reveal the composition of the sun and stars, and who are now making photography picture the heavens as they are, and even reveal phenomena which lie beyond the range of human vision, are the men who have taken astronomy out of its swaddling-clothes, and set it on its feet as a progressive science. But when one sees the depressing and repellent effect that has evidently been pro- ducéd upon the popular mind by the ordinary methods of presenting astronomy, one can not resist the temptation to utter a vigorous protest, and to declare that this glorious science is not the grinning mathematical skeleton that it has been represented to be. Perhaps one reason why the average educated man or woman knows so little of the starry heavens is because it is popularly supposed that only the most powerful telescopes and costly instruments of the observatory are capable of deal- ing with them. No greater mistake could be made. It does not require an optical instrument of any kind, nor much labor, as compared with that expended in the acquirement of some polished accomplishments regarded as indispensable, to give one an acquaintance with the stars and planets which will be not only pleasurable but useful. And with the aid of an opera-glass most interesting, gratifying, and, in some instances, scientifically valuable observations may be made in 4 ASTRONOMY WITH AN OPERA-@LASS. the heavens. I have more than once heard persons who knew nothing about the stars, and probably cared less, utter ex- clamations of surprise and delight when persuaded to look at certain parts of the sky with a good glass, and thereafter manifest an interest in astronomy of which they would for- merly have believed themselves incapable. Being convinced that whoever will survey the heavens with a good opera-glass will feel repaid many fold for his time and labor, I have undertaken to point. out some of the objects most worthy of attention, and some of the means of making acquaintance with the stars. 3 First, a word about the instrument to be used. Galileo made his famous discoveries with what was, in principle of construction, simply an opera-glass. This form of telescope was afterward abandoned because very high magnifying pow- ers could not be employed with it, and the field of view was restricted. But, on account of its brilliant illumination of objects looked at, and.its convenience of form, the opera-glass is still a valuable and, in some respects, unrivaled instrument of observation. In choosing an opera-glass, see first that the object-glasses are achromatic, although this caution is hardly necessary, for all modern opera-glasses, worthy of the name, are made with achromatic objectives. But there are great differences in the quality of the work. If a glass shows a colored fringe around a bright object, reject it. Let the diameter of the object- glasses, which are the large lenses in the end farthest from the eye, be not less than an inch and a half. The magnifying power should be at least three or four diameters. A familiar way of estimating the magnifying power is by looking at a brick wall through one barrel of the opera-glass with one eye, while the other eye sees the wall without the intervention of the glass. Then notice how many bricks seen by the naked eye are required to equal in thickness one brick seen through the glass. That number represents the magnifying power. INTRODUCTION. 5 The instrument used by the writer in making most of the observations for this book has object-glasses 1°6 inch in diam- eter, and a magnifying power of about 3°6 times. See that the fields of view given by the two barrels of the opera-glass coincide, or blend perfectly together. If one appears to partially overlap the other when looking at a distant object, the effect is very annoying. This fault arises from the barrels of the opera-glass being placed too far apart, so that their optical centers do not coin- cide with the centers of the observer’s eyes. Occasionally, on account of faulty cen- tering of the lenses, a double image is given of objects looked at, as illus- trated in the accompanying cut. In such a case the glass is worthless ; but if the effect is simply the addition of a small, crescent-shaped extension on one side of the field of view without any reduplication, the fault may be overlooked, though it is far better to select a glass that gives a perfectly round field. Some glasses have an arrangement for adjust- ing the distance between the barrels to suit the eyes of dif- ferent persons, and it would be well if all were made adjust- able in the same way. Don’t buy a cheap glass, but don’t waste your money on fancy mountings. What the Rev. T. W. Webb says of tele- scopes is equally true of opera-glasses: ‘‘Inferior articles may be showily got up, and the outside must go for nothing.” There are a few makers whose names, stamped upon the in- A VERY Bap FIE Lp. t 6 ASTRONOMY WITH AN OPERA-GLASS. strument, may generally be regarded as a guarantee of excel- lence. But the best test is that of actual performance. I have a field-glass which I found in a pawn-shop, that has no maker’s name upon it, but in some respects is quite capable of bearing comparison with the work of the best advertised opticians. And this leads me to say that, by the exercise of good judgment, one may occasionally purchase superior glasses at very reasonable prices in the pawn-shops. Ask to be shown the old and well-tried articles ; you may find among them a second-hand glass of fine optical properties. If the lenses are not injured, one need not trouble one’s self about the worn appearance of the outside of the instrument; so much the more evidence that somebody has found it well worth using. A good field or marine glass is in some respects better than an opera-glass for celestial observations. It possesses a much higher magnifying power, and this gives sometimes a decided advantage. But, on the other hand, its field of view is smaller, rendering it more difficult to find and hold objects. Besides, it does not present as brilliant views of scattered star-clusters as an opera-glass does. For the benefit of those who possess field-glasses, however, I have included in this brief survey certain objects that lie just beyond the reach of opera-glasses, but can be seen with the larger instruments. I have thought it advisable in the descriptions of the con- stellations which follow to give some account of their mytho- logical origin, both because of the historical interest which attaches to it, and because, while astronomers have long since banished the constellation figures from their maps, the names which the constellations continue to bear require some ex- planation, and they possess a literary and romantic interest which can not be altogether disregarded in a work that is not intended for purely scientific readers. CHAPTER I. THE STARS OF SPRING. HaAvInG selected your glass, the next thing is to find the stars. Of course, one could sweep over the heavens at ran- dom on a starry night and see many interesting things, but he would soon tire of such aimless occupation. The observer must know what he is looking at in order to derive any real pleasure or satisfaction from the sight. It really makes no difference at what time of the year such observations are begun, but for convenience I will sup- pose that they are begun in the spring. We can then follow the revolution of the heavens through a year, at the end of which the diligent observer will have acquired a competent knowledge of the constellations. The circular map, No. 1, represents the appearance of the heavens at midnight on the 1st of March, at eleven o’clock on the 15th of March, at ten o'clock on the Ist of April, at nine o’clock on the 15th of April, and at eight o’clock on the Ist of May. ‘The reason why a single map can thus be made to show the places of the stars at different hours in different months will be plain upon a little reflection. In consequence of the earth’s annual jour- ney around the sun, the whole heavens make one apparent revolution in a year. This revolution, it is clear, must be at the rate of 30° in a month, since the complete circuit com- prises 360°. But, in addition to the annual revolution, there is a diurnal revolution of the heavens which is caused by the earth’s daily rotation upon its axis, and this revolution must, for a similar reason, be performed at the rate of 15° for each “LS Va & ASTRONOMY WITH AN OPERA-GLASS. of the twenty-four hours. It follows that in two hours of the daily revolution the stars will change their places to the same ‘“HLYON SOUTH. Map 1. extent asin one month of the annual revolution. It follows also that, if one could watch the heavens throughout the whole twenty-four hours, and not be interrupted by daylight, he would behold the complete circuit of the stars just as he would do if, for a year, he should look at the heavens at a particular hour every night. Suppose that at nine o’clock on WEST. THE STARS OF SPRING. 9 the 1st of June we see the star Spica on the meridian ; in consequence of the rotation of the earth, two hours later, or at eleven o’clock, Spica will be 30° west of the meridian. But that is just the position which Spica would occupy at nine o’clock on the Ist of July, for in one month (sup- posing a month to be accurately the twelfth part of a year) the stars shift their places 30° toward the west. If, then, we should make a map of the stars for nine o’clock on the 1st of July, it would answer just as well for eleven o’clock on the 1st of June, or for seven o’clock on the 1st of August. The center of the map is the zenith, or point overhead. The reader must now exercise his imagination a little, for it is impossible to represent the true appearance of the concave of the heavens on flat paper. Holding the map over your head, with the points marked East, West, North, and South in their proper places, conceive of it as shaped like the inside of an open umbrella, the edge all around extending clear down to the horizon. Suppose you are facing the south, then you will see, up near the zenith, the constellation of Leo, which can be readily recognized on the map by six stars that mark out the figure of a sickle standing upright on its handle. The large star in the bottom of the handle is Regulus. Hav- ing fixed the appearance and situation of this constellation in your mind, go out-of-doors, face the south, and try to find the constellation in the sky. With a little application you will be sure to succeed. Using Leo as a basis of operations, your conquest of the sky will now proceed more rapidly. By reference to the map you will be able to recognize the twin stars of Gemini, south- west of the zenith and high up; the brilliant lone star, Pro- cyon, south of Gemini; the dazzling Sirius, flashing low down in the southwest ; Orion, with all his brilliants, blazing in the west; red Aldebaran and the Pleiades off to his right ; and Capella, bright as a diamond, high up above Orion, toward the north. In the southeast you will recognize the quadri- 2 10 ASTRONOMY WITH AN OPERA-GLASS. lateral of Corvus, with the remarkably white star Spica glit- tering east of it. ; Next face the north. If you are not just sure where north is, try a pocket-compass. This advice is by no means unnecessary, for there are many intelligent persons who are unable to indicate true north within many degrees, though standing on their own doorstep. Having found the north point as near as you can, look upward about forty degrees from the horizon, and you will see the lone twinkler called the north or pole star. Forty degrees is a little less than half-way from the horizon to the zenith. By the aid of the map, again, you will be able to find, high up in the northeast, near the zenith, the large dipper- shaped figure in Ursa Major, and, when you have once no- ticed that the two stars in the outer edge of the bowl of the Dipper point almost directly to the pole-star, you will have an unfailing means of picking out the latter star hereafter, when in doubt.* Continuing the curve of the Dipper-handle, in the northeast, your eye will be led to a bright reddish star, which is Arcturus, in the constellation Bodtes. In the same way you will be able to find the constellations Cassiopeia, Cepheus, Draco, and Perseus. Don’t expect to accomplish it all in an hour. You may have to devote two or three evenings to such observation, and make many trips in- doors to consult the map, before you have mastered the sub- ject ; but when you have done it you will feel amply repaid for your exertions, and you will have made for yourself silent friends in the heavens that will beam kindly upon you, like old neighbors, on whatever side of the world you may wander. Having fixed the general outlines and location of the con- stellations in your mind, and learned to recognize the chief stars, take your opera-glass and begin with the constellation * Let the reader remember that the distance between the two stars in the brim of the bowl of the Dipper is about ten degrees, and he will have a measuring-stick that he can apply in estimating other distances in the heavens. THE STARS OF SPRING. 11 Leo and the star Regulus. Contrive to have some convenient rest for your arms in holding the glass, and thus obtain not only comfort but steadiness of vision. A lazy-back chair makes a capital observing-seat. Be very particular, too, to get a sharp focus. Remember that no two persons’ eyes are alike, and that even the eyes of the same observer occasion- ally require a change. In looking for a difficult object, I have sometimes suddenly brought the sought-for phenom- enon into view by a slight turn of the focusing-screw. You will at once be gratified by the increased brilliancy of the star as seen by the glass. If the night is clear, it will glow like a diamond. Yet Regulus, although ranked as a first- magnitude star, and of great repute among the ancient as- trologers, is far inferior in brilliancy to such stars as Capella and Arcturus, to say nothing of Sirius. By consulting map No. 2 you will next be able to find the celebrated star bearing the name of the Greek letter Gamma (y). If you hada telescope, you would see this star as a close and beautiful double, of contrasted colors. But it is optically double, even with an opera-glass. You can not fail to see a small star near it, looking quite close if the magnify- ing power of your glass is less than three times. You will be struck by the surprising change of color in turning from Regulus to Gamma—the former is white and the latter deep yellow. It will be well to look first at one and then at the other, several times, for this is a good instance of what you will meet with many times in your future surveys of the heavens—a striking contrast of color in neighboring stars. One can thus comprehend that there is more than one sense in which to understand the Scriptural declaration that ‘‘one star differeth from another in glory.”’ The radiant point of the famous November meteors, which, in 1833 and 1866, filled the sky with fiery showers, is nearGamma. Turn next to the star in Leo marked Zeta (¢). If your glass is a pretty large and good one, and your eye keen, you will easily see three 12 ASTRONOMY WITH AN OPERA-GLASS. minute companion stars keeping company with Zeta, two on the southeast, and one, much closer, toward the north. The nearest of the two on the south is faint, being only between the eighth and ninth magnitude, and will probably severely test your powers of vision. Next look at Epsilon (e), and you will find near it two seventh-magnitude companions, making a beautiful little triangle. Away at the eastern end of the constellation, in the tail of the imaginary Lion, upon whose. breast shines Regulus, is the star Beta (8) Leonis, also called Denebola. It is almost as bright as its leader, Regulus, and you will probably be able to catch a tinge of blue in its rays. South of Denebola, at a distance of nineteen minutes of arc, or somewhat more than half the apparent diameter of the moon, you will see a little star of the sixth magnitude, which is one of the several THE STARS OF SPRING. 18 “companions’’ for which Denebola is celebrated. There is another star of the eighth magnitude in the same direction from Denebola, but at a distance of less than five minutes, and this you may be able to glimpse with a powerful field- glass, under favorable conditions. I have seen it well with a field-glass of 1°6-inch aperture, and a magnifying power of seven times. But it requires an experienced eye and steady vision to catch this shy twinkler. When looking for a faint and difficult object, the plan pursued by telescopists is to avert the eye from the precise point upon which the attention is fixed, in order to bring a more sensitive part of the retina into play than that usually employed. Look toward the edge of the field of view, while the object you are seeking is in the center, and then, if it can be seen at all with your glass, you will catch sight of it, as it were, out of the corner of your eye. The effect of seeing a faint star in this way, in the neighborhood of a large one, _ whose rays hide it from direct vision, is sometimes very amusing. The little star seems to dart out into view as through a curtain, perfectly distinct, though as immeasur- ably minute as the point of a needle. But the instant you direct your eyes straight at it, presto! it is gone. And so it will dodge in and out of sight as often as you turn your eyes. If you will sweep carefully over the whole extent of Leo, whose chief stars are marked with their Greek-letter names on our little map, you will be impressed with the power of your glass to bring into sight many faint stars in regions that seem barren to the naked eye. An opera-glass of 1°5 aper- ture will show ten times as many stars as the naked eye can see. A word about the ‘‘ Lion” which this constellation is supposed to represent. It requires a vivid imagination to perceive the outlines of the celestial king of beasts among the stars, and yet somebody taught the people of ancient India and the old Egyptians to see him there. and there he 14 ASTRONOMY WITH AN OPERA-GLASS. has remained since the dawn of history. Modern astrono- mers strike him out of their charts, together with all the picturesque multitude of beasts and birds and men and women that bear him company, but they can not altogether banish him, or any of his congeners, for the old names, and, practically, the old outlines of the constellations are retained, and always will be retained. The Lion is the most con- spicuous figure in the celebrated zodiac of Dendera; and, indeed, there is evidence that before the story of Hercules and his labors was told this lion was already imagined shin- ing among the stars. It was characteristic of the Greeks that they seized him for their own, and tried to rob him of his real antiquity by pretending that. Jupiter had placed him among the stars in commemoration of Hercules’s vic- tory over the Nemzan lion. In the Hebrew zodiac Leo represented the Lion of Judah. It was thus always a lion that the ancients thought they saw in this constellation. In the old star-maps the Lion is represented as in the act of springing upon his prey. His face is to the west, and the star Regulus is in his heart. The sickle-shaped figure covers his breast and head, Gamma being in the shoulder, Zeta in the mane of the neck, Mu and. Epsilon in the cheek, and Lambda in the jaws. The fore-paws are drawn up to the breast and represented by the stars Zi and Omicron. Dene- bola is in the tuft of the tail. The hind-legs are extended downward at full length, in the act of springing. Starting from the star Delta in the hip, the row consisting of Theta, Jota, Tau, and Upsilon, shows the line of the hind-legs. Leo had an unsavory reputation among the ancients be- cause of his supposed influence upon the weather. The greatest heat of summer was felt when the sun was in this constellation : ** Most scorching is the chariot of the Sun, And waving spikes no longer hide the furrows _ When he begins to travel with the Lion.” THE STARS OF SPRING. 15 Looking now westwardly from the Sickle of Leo, at a distance about equal to twice the length of the Sickle, your eye will be caught by a small silvery spot in the sky lying nearly between two rather faint stars. This is the famous Preesepe, or Manger, in the center of the constellation Can- cer. The two stars on either side of it are called the Aselli, or the Ass’s Colts, and the imagination of the ancients pict- ured them feeding from their silver manger. Turn your glass upon the Manger and you will see that it consists of a crowd of little stars, so small and numerous that you will probably not undertake to count them, unless you are using a large field-glass. Galileo has left a delightful description of his surprise and gratification when he aimed his telescope at this curious cluster and other similar aggregations of stars and discovered what they really were. Using his best instrument, he was able to count thirty-six stars in the Man- ger. The Manger was a famous weather-sign in olden times, and Aratus, in his ‘‘ Diosemia,” advises his readers to— 6¢ e . . watch the Manger: like a little mist Far north in Cancer’s territory it floats. Its confines are two faintly glimmering stars ; These are two asses that a manger parts, Which suddenly, when all the sky is clear, Sometimes quite vanishes, and the two stars Seem to have closer moved their sundered orbs. No feeble tempest then will soak the leas ; A murky manger with both stars Shining unaltered is a sign of rain.” Like other old weather-saws, this probably possesses a gleam of sense, for it is only when the atmosphere is per- fectly transparent that the Manger can be clearly seen ; when the airis thick with mist, the harbinger of coming storm, it fades from sight. The constellation Cancer, or the Crab, was represented by the Egyptians under the figure of a scarabeus. The ob- server will probably think that it is as easy to see a beetle as 16 ASTRONOMY WITH AN OPERA-G@GLASS. ‘acrab there. Cancer, like Leo, is one of the twelve constella- tions of the Zodiac, the name applied to the imaginary zone 16° degrees wide and extending completely around the heay- ens, the center of which is the ecliptic or annual path of the sun. The names of these zodiacal constellations, in their order, beginning at the west and counting round the circle, are: Aries, Taurus, Gemini, Cancer, Leo, Virgo, Libra, Scorpio, Sagittarius, Capricornus, Aquarius, and Pisces. Cancer has given its name to the circle called the Tropic of Cancer, which indicates the greatest northerly declination of the sun in summer, and which he attains on the 21st or 22d of June. But, in consequence of the precession of the equi- noxes, all of the zodiacal constellations are continually shift- ing toward the east, and Cancer has passed away from the place of the summer solstice, which is now to be found in Gemini. . Below the Manger, a little way toward the south, your eye will be caught by a group of four or five stars of about the same brightness as the Aselli. This marks the head of Hydra, and the glass will show a striking and beautiful geometrical arrangement of the stars composing it. Hydra is a very long constellation, and trending southward and eastward from the head it passes underneath Leo, and, sweeping pretty close down to the horizon, winds away under Corvus, the tail reaching to the eastern horizon. The length of this skyey serpent is about 100°. Its stars are all faint, except Alphard, or the Hydra’s Heart, a second-magnitude star, remarkable for its lonely situation, southwest of Regulus. A line from Gamma Leonis through Regulus points it out. It is worth looking at with the glass on account of its rich orange-tint. Hydra is fabled to be the hundred-headed monster that was slain by Hercules. It must be confessed that there is nothing very monstrous about it now except its length. The most timid can look upon it without suspecting its grisly ~ origin. 4 THE STARS OF SPRING. 17% Coming back to the Manger as a starting-point, look well up to the north and west, and at a distance somewhat less than that between Regulus and the Manger you will seea pair of first-magnitude stars, which you will hardly need to be informed are the celebrated Twins, from which the con- stellation Gemini takes its name. The star marked a in the map is Castor, and the star marked @ is Pollux. No classi- cal reader needs to be reminded of the romantic origin of these names. A sharp contrast in the color of Castor and Pollux comes out as soon as the glass is turned upon them. Castor is white, with occasionally, perhaps, a suspicion of a green ray in its light. Pollux is deep yellow. Castor is a celebrated double star, but its components are far too close to be sepa- rated with an opera-glass, or even the most powerful field- glass. You will be at once interested by the singular cortége of small stars by which both Castor and Pollux are sur- rounded. These little attendant stars, for such they seem, are arrayed. in symmetrical groups — pairs, triangles, and other figures—which, it seems difficult to believe, could be unintentional, although it would be still more difficult to sug- gest any reason why they should be arranged in that way. Our map will show you the position of the principal stars of the constellation. Castor and Pollux are in the heads of the Twins, while the row of stars shown in the map Xi (€), Gamma (vy), Nu (v), Mu (wz), and Eta (7), marks their feet, which are dipped in the edge of the Milky-Way. One can spend a profitable and pleasurable half-hour in exploring the wonders of Gemini. The whole constellation, from head to foot, is gemmed with stars which escape the naked eye, but it sparkles like a bead-spangled garment when viewed with the glass. Owing to the presence of the Milky-Way, the spectacle around the feet of the Twins is particularly magnificent. And here the possessor of a good opera-glass can get a fine view of a celebrated star-cluster known in the 18 ASTRONOMY WITH AN OPERA-GLASS. catalogues as 835 M. It is situated a little distance northwest of the star Eta, and is visible to the naked eye, on a clear, AURIGA GEMINI! xd a4 mee CANIS MINOR * Map 3. moonless night, as a nebulous speck. With a good glass you will see two wonderful streams of little stars starting, one from Eta and the other from Mu, and running parallel toward the northwest; 35 M is situated between these star-streams. The stars in the cluster are so closely aggregated that you will be able to clearly separate only the outlying ones. The general aspect is like that of a piece of frosted silver over which a twinkling light is playing. A field-glass brings out more of the component stars. The splendor of this starry congregation, viewed with a powerful telescope, may be guessed at from Admiral Smyth’s picturesque description : ‘Tt presents a gorgeous field of stars, from the ninth to the sixteenth magnitude, but with the center of the mass less rich than the rest. From the small stars being inclined to form curves of three or four, and often with a large one at the root of the curve, it somewhat reminds one of the burst- ing of a sky-rocket.” And Webb adds that there is an THE STARS OF SPRING. 19 ‘‘elegant festoon near the center, starting with a reddish star.” No one can gaze upon this marvelous phenomenon, even with the comparatively low powers of an opera-glass, and re- flect that all these swarming dots of light are really suns, without a stunning sense of the immensity of the material universe. It is an interesting fact that the summer solstice, or the point which the sun occupies when it attains its greatest north- erly declination, on the longest day of the year, is close by this great cluster in Gemini. In the glare of the sunshine those swarming stars are then concealed from our sight, but with the mind’s eye we can look past and beyond our sun, across the incomprehensible chasm of space, and behold them still shining, their commingled rays making our great God of Day seem but a lonely wanderer in the expanse of the universe. It was only a short distance southwest of this cluster that one of the most celebrated discoveries in astronomy was made. There, on the evening of March 13, _1781, William Herschel observed a star whose singular aspect led him to put a higher magnifying power on his telescope. The higher power showed that the object was not a star but a planet, or a comet, as Herschel at first supposed. It was the planet Ura- nus, whose discovery ‘‘at one stroke doubled the breadth of the sun’s dominions.’’ | The constellation of Gemini, as the names of its two chief stars indicate, had its origin in the classic story of the twin sons of Jupiter and Leda: “Fair Leda’s twins, in time to stars decreed, One fought on foot, one curbed the fiery steed.” Castor and Pollux were regarded by both the Greeks and the Romans as the patrons of navigation, and this fact crops out very curiously in the adventures of St. Paul. After his disastrous shipwreck on the island of Melita he embarked 20 ASTRONOMY WITH AN OPERA-GLASS. again on a more prosperous voyage in a ship bearing the name of these very brothers. ‘‘ And after three months,” writes the celebrated apostle (Acts xxviii, 11) ‘‘ we departed in a ship of Alexandria, which had wintered in the isle, whose sign was Castor and Pollux.” We may be certain that Paul was acquainted with the constellation of Gemini, not only because he was skilled in the learning of his times, but because, in his speech on Mars Hill, he quoted a line from the opening stanzas of Aratus’s ‘‘ Phenomena,” a poem in which the constellations are described. The map will enable you next to find Procyon, or the Lit- tle Dog-Star, more than twenty degrees south of Castor and Pollux, and almost directly below the Manger. This star will interest you by its golden-yellow color and its brightness, although it is far inferior in the latter respect to Sirius, or the Great Dog-Star, which you will see flashing splendidly far down beneath Procyon in the southwest. About four de- grees northwest of Procyon is a third-magnitude star, called Gomelza, and the glass will show you two small stars which make a right-angled triangle with it, the nearer one being remarkable for its ruddy color. Procyon is especially interesting because it is attended by an invisible star, which, while it has escaped all efforts to de- tect it with powerful telescopes, nevertheless reveals its pres- ence by the effect of its attraction upon Procyon. It is a curious fact that both of the so-called Dog-Stars are thus attended by obscure or dusky companion-stars, which, not- withstanding their lack of luminosity, are of great magni- tude. In the case of Sirius, the improvement in telescopes has brought the mysterious attendant into view, but Pro- cyon’s mate remains hidden from our eyes. But it can not escape the ken of the mathematician, whose penetrating men- tal vision has, in more than one instance, outstripped the dis- coveries of the telescope. Almost half a century ago the famous Bessel announced his conclusion—in the light of later THE STARS OF SPRING. 21 developments it may well be called discovery—that both Sir- ius and Procyon were binary systems, consisting each of a visible and an invisible star. He calculated the probable period of revolution, and found it to be, in each case, ap- proximately fifty years. Sixteen years after Bessel’s death, one of Alvan Clark’s unrivaled telescopes at last revealed the strange companion of Sirius, a huge body, half as massive as the giant Dog-Star itself, but ten thousand times less brill- iant, and more recent observations have shown that its pe- riod of revolution is within six or seven months of the fifty years assigned by Bessel. If some of the enormous tele- scopes that have been constructed in the past few years should succeed in rendering Procyon’s companion visible also, it is highly probable that Bessel’s prediction would receive another substantial fulfillment. The mythological history of Canis Minor is somewhat ob- scure. According to various accounts it represents one of Diana’s hunting-dogs, one of Orion’s hounds, the Egyptian dog-headed god Anubis, and one of the dogs that devoured their master Actzeon after Diana had turned him into a stag. The mystical Dr. Seiss leaves all the ancient myth-makers far in the rear, and advances a very curious theory of his own about this constellation, in his ‘‘ Gospel in the Stars,” which is worth quoting as an example of the grotesque fancies that even in our day sometimes possess the minds of men when they venture beyond the safe confines of this terraqueous globe. After summarizing the various myths we have mentioned, he proceeds to identify Procyon, put- ting the name of the chief star for the constellation, ‘‘as the starry symbol of those heavenly armies which came forth along with the King of kings and Lord of lords to the battle of the great day of God Almighty, to make an end of mis- rule and usurpation on earth, and clear it of all the wild beasts which have been devastating it for these many ages.” The reader will wonder all the more at this rhapsody 92 ASTRONOMY WITH AN OPERA-GLASS. after he has succeeded in picking out the modest Little Dog in the sky. Sirius, Orion, Aldebaran, and the Pleiades, all of which you will perceive in the west and southwest, are generally too much involved in the mists of the horizon to be seen to the best advantage at this season, although it will pay you to take a look through the glass at Sirius. But the splendid star Capella, in the constellation Auriga, may claim a mo- ment’s attention. You will find it high up in the northwest, half-way between Orion and the pole-star, and to the right of the Twins. It has no rival near, and its creamy-white light makes it one of the most beautiful as well as one of the most brilliant stars in the heavens. Its constitution, as revealed by the spectroscope, resembles that of our sun, but the sun would make but a sorry figure if removed to the side of this giant star. About seven and a half degrees above Capella, and a little to the left, you will see a second-mag- nitude star called Menkalina. Two and a half times as far to the left, or south, in the direction of Orion, is another star of equal brightness to Menkalina. This is El Nath, and marks the place where the foot of Auriga, or the Charioteer, rests upon the point of the horn of Taurus. Capella, Men- kalina, and El Nath make a long triangle which covers the central part of Auriga. The naked eye shows two or three misty-looking spots within this triangle, one to the right of El Nath, one in the upper or eastern part of the constel- lation, near the third-magnitude star Theta (@), and another on a line drawn from Capella to El Nath, but much nearer to Capella. Turn your glass upon these spots, and you will be delighted by the beauty of the little stars to whose united rays they are due. : El Nath has around it some very remarkable rows of small stars, and the whole constellation of Auriga, like that of Gemini, glitters with star-dust, for the Milky-Way runs directly through it. THE STARS OF SPRING. 98 With a powerful field-glass you may try a glimpse at the rich star-clusters marked 38 M, 37 M, and 33%. The mythology of Auriga is not clear, but the ancients seem to have been of one mind in regarding the constella- tion as repre- senting the fig- “PERSEUS ure of a man carrying a goat and her two kids in his arms. Auri- ga was also looked upon as a_ benefi- cent constella- GEMINI tion, and the goat and kids were believed to be on the watch to rescue shipwrecked sailors. As Capella, which represents the fabled goat, shines - nearly overhead in winter, and would ordinarily be the first bright star to beam down through the breaking clouds of a storm at that season, it is not diffftult to imagine how it got its reputation as the seaman’s friend. Dr. Seiss has so spir ited a description of the imaginary figure contained in this constellation that I can not refrain from quoting it: ‘The figure itself is that of a mighty man seated on the Milky-Way, holding a band or ribbon in his right hand, and with his left arm holding up on his shoulder a she-goat which clings to his neck and looks out in astonishment upon the terrible bull; while in his lap are two frightened little kids which he supports with his great hand.” It is scarcely necessary to add that Dr. Seiss insists that Auriga, as a constellation, was invented long before the time of the Greeks, and was intended prophetically to represent that Good Shepherd who was to come and rescue the sinful world. Map 4. 94 ASTRONOMY WITH AN OPERA-@GLASS. If any reader wishes to exercise his fancy by trying to trace the outlines of this figure, he will find the head of Auriga marked by the star Delta (6) and the little group near it. Capella, in the heart of the Goat, is just below his left shoulder, and Menkalina marks his right shoulder. El Nath is in his right foot, and Iota (c) in his left foot. The stars Epsilon (e), Zeta (¢), Eta (y), and Lambda (A) shine in the kids which lie in Auriga’s lap. The faint stars scat- tered over the eastern part of the constellation are sometimes represented as forming a whip with many lashes, which the giant flourishes with his right hand. Let us turn back to Denebola in the Lion’s Tail. Now glance from it down into the southeast, and you will see a brilliant star flashing well above the horizon. This is Spica. the chief twinkler of Virgo, and it is marked on our circu- lar map. Then look into the northwest, and at about the same distance from Denebola, but higher above the horizon than Spica, you will catch the sparkling of a large, reddish star. It is Arcturus in Bootes. The three, Denebola, Spica, and Arcturus, mark the corners of a great equilateral tri- angle. Nearly on a line between Denebola and Arcturus, and somewhat nearer to the former, you will perceive a curious twinkling, as if gossamers spangled with dew-drops were entangled there. One might think the old woman of the nursery rhyme who went to sweep the cobwebs out of the sky had skipped this corner, or else that its delicate beauty had preserved it even from her housewifely instincts. This is the little constellation called Berenice’s Hair. Your opera- glass will enable you to count twenty or thirty of the largest stars composing this cluster, which are arranged, as so often happens, with a striking appearance of geometrical design. The constellation has a very romantic history. It is related that the young Queen Berenice, when her husband was called away to the wars, vowed to sacrifice her beautiful tresses to Venus if he returned victorious over his enemies. tod THE STARS OF SPRING. 95 He did return home in triumph, and Berenice, true to her vow, cut off her hair and bore it to the Temple of Venus. But the same night it disappeared. The king was furious, and the queen wept bitterly over the loss. There is no tell- ing what might have happened to tle guardians of the tem- ple, had not a celebrated astronomer named Conon led the young king and queen aside in the evening and showed them the missing locks shining transfigured in the sky. He assured them that Venus had placed Berenice’s lustrous ringlets among the stars, and, as they were not skilled in celestial lore, they were quite ready to believe that the sil- very swarm they saw near Arcturus had never been there before. And so for centuries the world has recognized the constellation of Berenice’s Hair. Look next at Corvus and Crater, the Crow and the Cup, two little constellations which you will discover on the cir- cular map, and of which we give a separate representation in Map 5. You will find that the stars Delta (6) and Eta (n), in the upper left-hand corner of the quadrilateral figure of ‘Corvus, make a striking appearance. The little star Zeta (£) is a very pretty double for an opera-glass. There is a very faint pair of stars close below and to the right of Beta ((). This forms a severe test. Only a good opera-glass will show these two stars as a single faint point of light. A field-glass, however, will show both, one being considerably fainter than the other. Crater is worth sweeping over for the pretty com- binations of stars to be found in it. You will observe that the interminable Hydra extends his lengthening cvils along under both of the constellations. In fact, both the Cup and the Crow are represented as standing upon the huge serpent. The outlines of a cup are tolerably well indicated by the stars included under the name Crater, but the constellation of the Crow might as well have borne any other name so far as any traceable likeness is concerned. One of the legends concerning Corvus avers that it is the 3 26 ASTRONOMY WITH AN OPERA-GLASS. daughter of the King of Phocis, who was transformed tnto a crow to escape the pursuit of Neptune. She is certainly safe in her present guise. Arcturus and Spica, and their companions, may be left for observation to a more convenient season, when, having risen higher, they can _ be studied to bet- ter advantage. It will be well, | however, to Bee is merely glance ai Hag tf *7 5 CRATER. | at them with the glass in or- der to note the great difference of color—Spica being brilliant- ly white and Arcturus al- most red. We will now turn to the north. You have already been told how to find the pole-star. Look at it with your glass. The pole-star is a famous double, but its minute companion can only be seen with a telescope. As so often happens, however, it has another companion for the opera-glass, and this latter is sufficiently close and small to make an interest- ing test for an inexperienced observer armed with a glass of small power. It must be looked for pretty close to the rays of the large star, with such a glass It is of the seventh magnitude. With a large field-glass several smaller compan- lons may be seen, and a very excellent glass may show an 8’5- magnitude star almost hidden in the rays of the seventh- magnitude companion. With the aid of map No. 6 find in Ursa Minor, which is CORVUS THE STARS OF SPRING. 27 the constellation to which the pole-star belongs, the star Beta (8), which is also called Kochab (the star marked a in the map is the pole- star). Kochab has Greece ee att apairoffaint stars | ie : cane 2 nearly north of it, 7 ui +c : ay about one degree : os 4 ‘y distant. With a [im Paes ie small glass these may appear as a single star, but a stronger glass will show them _ sepa- rately. And now for Ursa Major and the Great Dipper —Draco, Cepheus, Cassiopeia, and the other constellations represented on the circular map, being rather too near the horizon for effect- ive observation at this time of the year. First, as the eas- iest object, look at the star in the middle of the handle of the Dipper (this handle forms the tail of Ursa Major), and a little attention will: show you, without the aid of a glass, if your eye-sight is good, that the star is double. A smaller star seems to be almost in contact with it. The larger of these two stars is called Mizar and the smaller Alcor—the Horse and his Rider the Arabs said. Your glass will, of course, greatly increase the distance between Alcor and Mizar, and will also bring out a clear difference of color dis- tinguishing them. Now, if you have a very powerful glass, you may be able to see the Sidus Ludovicianum, a minute star which a German astronomer discovered more than a hundred and fifty years ago, and, strangely enough, taking it for a planet, named it aftera German prince. The position 28 ASTRONOMY WITH AN OPERA-GLASS. of the Sidus Ludovicianum, with reference to Mizar and Alcor, is represented in the accompanying sketch. You must look very sharply if you expect to see it, and your opera-glass will have to be a large and strong one. A field- glass, however, can not fail to show it. Sweep along the whole length of the Dipper’s handle, and you will discover many fine fields of stars. Then look at the star Alpha (a) in the outer edge of the bowl nearest to the pole-star. There is a faint star, of about the eighth magni- tude, near it, in the direction of Beta (8). This will prove a very difficult test. You will have to try it with averted vision. If you have a field-glass, catch it first with that, and, having thus fixed its position in your mind, try to find it with the opera-glass. Its distance is a little over half that between Mizar and Alcor. It is of a reddish color. You will notice nearly overhead three pairs of pretty bright stars in a long, bending row, about half-way between Leo and the Dipper. These mark three of Ursa Major’s feet, and each of the pairs is well worth looking at with a glass, as they are beautifully grouped with stars invisible to the naked eye. The letters used to designate the stars forming these pairs will be found upon our map of Ursa Major. The scattered group of faint stars beyond the bowl of the Dipper forms the Bear’s head, and you will find that also a field worth a few min- utes’ exploration. The two bears, Ursa Major and Ursa Minor, swinging around the pole of the heavens, have been conspicuous in the star-lore of all ages. According to fable, they represent Mizar, ALCOR, AND THE SIDUS LUDOVICIANUM. THE STARS OF SPRING. 29 the nymph Calisto, with whom Jupiter was in love, and her son Arcas, who were both turned into bears by Juno, where- upon Jupiter, being unable to restore their form, did the next best thing he could by placing them among the stars. Ursa Major is Calisto, or Helica, as the Greeks called the con- stellation. The Greek name of Ursa Minor was Cynosura. The use of the pole-star in navigation dates back at least to the time of the Phcenicians. The observer will note the uncomfortable position of Ursa Minor, attached to the pole by the end of its long tail. But, after all, no one can expect to derive from such studies as these any genuine pleasure or satisfaction unless he is mindful of the real meaning of what he sees. The actual truth seems almost too stupendous for belief. The mind must be brought into an attitude of profound contem- plation in order to appreciate it. From this globe we can look out in every direction into the open and boundless uni- verse. Blinded and dazzled during the day by the blaze of that star, of which the earth is a near and humble dependent, we are shut inas by acurtain. But at night, when our own star is hidden, our vision ranges into the depths of creation, and we behold them sparkling with a multitude of other suns. With so simple an aid as that of an opera-glass we penetrate still deeper into the profundities of space, and thousands more of these strange, far-away suns come into sight. They are arranged in pairs, sets, rows, streams, clus- ters—here they gleam alone in distant splendor, there they glow and flash in mighty swarms. This is a look into heaven more splendid than the imagination of Bunyan pictured ; here is a celestial city whose temples are suns, and whose streets are the pathways of light. CHAPTER II. THE STARS OF SUMMER. LET us now suppose that the Earth has advanced for thrée months in its orbit since we studied the stars of spring, and that, in consequence, the heavens have made one quarter of an apparent revolution. Then we shall find that the stars which in spring shone above the western horizon have been carried down out of sight, while the constellations that were then in the east have now climbed to the zenith, or passed over to the west, and a fresh set of stars has taken their place in the east. In the present chapter we shall deal with what may be called the stars of summer; and, in order to fur- nish occupation for the observer with an opera-glass through. out the summer months, I have endeavored to so choose the constellations in which our explorations will be made, that some of them shall be favorably situated in each of the months of June, July, and August. The circular map represents the heavens at midnight on the 1st of June; at eleven o'clock, on the 15th of June; at ten o'clock, on the Ist of July; at nine o’clock, on the 15th of July; and at eight o’clock, on the Ist of August. Remembering that the center of the map is the point over his head, and that the edge of it represents the circle of the horizon, the reader, by a little attention and comparison with the sky, will be able to fix in his mind the relative situation of the various constellations. The maps that follow will show him these constellations on a larger scale, and give him the names of their chief stars. “L8VR THE STARS OF SUMMER. dl The observer need not wait until midnight on the 1st of June in order to find some of the constellations included “HLYON «x * guvd073Wb9 - = genres HAIR AS DQ. == a Sie ~ NiHd 700 WEST. yew? 02 NY) ol" He SOUTH. Map 7. inourmap. Earlier in the evening, at about that date, say at nine o’clock, he will be able to see many of these con- stellations, but he must look for them farther toward the east than they are represented in the map. The bright stars in Bootes and Virgo, for instance, instead of being over in $2 ASTRONOMY WITH AN OPERA-GLASS. the southwest, as in the map, will be near the meridian ; while Lyra, instead of shining high overhead, will be found climbing up out of the northeast. It would be well to begin at nine o’clock, about the 1st of June, and watch the motions of the heavens for two or three hours. At the commence- ment of the observations you will find the stars in Bodtes, Virgo, and Lyra in the positions I have just mentioned, while half-way down the western sky will be seen the Sickle of Leo. The brilliant Procyon and Capella will be found almost ready to set in the west and northwest, respectively. Between Procyon and Capella, and higher above the horizon, shine the twin stars in Gemini. In an hour Procyon, Capella, and the Twins will be set- ting, and Spica will be well past the meridian. In another hour the observer will perceive that the constellations are approaching the places given to them in our map, and at midnight he will find them all in their assigned positions. A single evening spent in observations of this sort will teach him more about the places of the stars than he could learn from a dozen books. Taking, now, the largest opera-glass you can get (I have before said that the diameter of the object-glasses should not be less than 1°5 inch, and, I may add, the larger they are the better), find the constellation Scorpio, and its chief star An- tares. The map shows you where to look for it at midnight on the 1st of June. If you prefer to begin at nine o’clock at that date, then, instead of looking directly in the south for Scorpio, you must expect to see it just rising in the southeast. You will recognize Antares by its fiery color, as well as by the striking arrangement of its surrounding stars. There are few constellations which bear so close a resemblance to the objects they are named after as Scorpio. It does not require a very violent exercise of the imagination to see in this long, winding trail of stars a gigantic scorpion, with its head to the west, and flourishing its upraised sting THE STARS OF SUMMER. 33 that glitters with a pair of twin stars, as if ready to strike. Readers of the old story of Phaeton’s disastrous attempt to drive the chariot of the Sun for a day will remember it was the sight of this threatening monster that so terrified the ambitious youth as he dashed along the Zodiac, that he lost control of Apollo’s horses, and came near burning the earth up by running the Sun into it. Antares rather gains in redness when viewed with a glass. Its color is very remarkable, and it is a curious circumstance that with powerful telescopes a small, bright-green star is seen apparently almost touching it. Antares belongs to Sec- chi’s third type of suns, that in which the spectroscopic appearances suggest the existence of a powerfully absorp- tive atmosphere, and which are believed on various grounds to be, as Lockyer has said, ‘‘in the last visible stage of cooling”; in other words, almost extinct. This great, red star probably in actual size exceeds our sun, and no one can help feeling the sublime nature of those studies which give us reason to think that here we can actually behold almost the expiring throes of a giant brother of our giant sun. Only, the lifetime of a sun is many millions of years, and its gradual extinction, even after it has reached a stage as advanced as that of Antares is supposed to be, may occupy a longer time than the whole duration of the human race. A little close inspection with the naked eye will show three fifth- or sixth-magnitude stars above Antares and Sig- ma (c), which form, with those stars, the figure of an irregu- lar pentagon. An opera-glass shows this figure very plainly. The nearest of these stars to Antares, the one directly above it, is known by the number 22, and belongs to Scorpio, while the farthest away, which marks the northernmost corner of the pentagon, is Rho in Ophiuchus. Try a powerful field- glass upon the two stars just named. Take 22 first. You will without much difficulty perceive that it has a little star 34 ASTRONOMY WITH AN OPERA-GLASS. under its wing, below and to the right, and more than twice as far away above it there is another faint star. Then turn to Rho. Look sharp and you will catch sight of two companion stars, one close to Rho on the right and a little below, and the other still closer and directly above Rho. The latter is quite difficult to be seen distinctly, but the sight is a very pretty one. | The opera-glass will show a number of faint stars scat- tered around Antares. Turn now to Beta (8) in Scorpio, with the glass. A very pretty pair of stars will be seen hanging below 8. Sweeping downward from this point to the horizon you will find many beautiful star-fields. The star marked Nu (v) is a double which you will be able to separate with a powerful field-glass, the distance between its components being 40”. | And next let us look at a star-cluster. You will see on Map No. 8 an object marked 4 M, near Antares. Its designa- & 2 a ~V ame < 8180 ee kG ies eg * TT 1 x p Map 8. tion means that it is No. 4in Messier’s catalogue of nebule. It is not a true nebula, but a closely compacted cluster of THE STARS OF SUMMER. 35, stars. With the opera-glass, if you are looking in a clear and moonless night, you will see it as a curious nebulous speck. With a field-glass its real nature is more apparent, and it is seen to blaze brighter toward the center. It is, in fact, one of those universes within the universe where thou- sands of suns are associated together by some unknown law of aggregation into assemblages of whose splendor the slight view that we can get gives us but the faintest conception. The object above and to the right of Antares, marked in the map 80 M., is a nebula, and although the nebula itself is too small to be seen with an opera-glass (a field-glass shows it as a mere wisp of light), yet there is a pretty array of small stars in its neighborhood worth looking at. Besides, this nebula is of special interest, because in 1860 a star suddenly took its place. At least, that is what seemed to have hap- pened. What really did occur, probably, was that a variable or temporary star, situated between us and the nebula, and ordinarily too faint to be perceived, received a sudden and enormous accession of light, and blazed up so brightly as to blot out of sight the faint nebula behind it. If this star should make its appearance again, it could easily be seen with an opera-glass, and so it will not be useless for the reader to know where to look for it. The quarter of the heavens with which we are now dealing is famous for these celestial conflagrations, if so they may be called. The first temporary star of which there is any record appeared in the constellation of the Scorpion, near the head, 134 years before Christ. It must have been a most extraordinary phenome- non, for it attracted attention all over the world, and both Greek and Chinese annals contain descriptions of it. In 393 A. D. a temporary star shone out in the tail of Scorpio. In 827 A. D. Arabian astronomers, under the Caliph Al-Mamoun, the son of Haroun-al-Raschid, who broke into the great pyra- mid, observed a temporary star, that shone for four months in the constellation of the Scorpion. In 12038 there was a 836 ASTRONOMY WITH AN OPERA-GLASS. temporary star, of a bluish color, in the tail of Scorpio, and in 1578 another in the head of the constellation. Besides these there are records of the appearance of four temporary stars in the neighboring constellation of Ophiuchus, one of which, that of 1604, is very famous, and will be described later on. It is conceivable that these strange outbursts in and near Scorpio may have had some effect in causing this constellation to be regarded by the ancients as malign in its influence. | We shall presently see some examples of star-clusters and nebulee with which the instruments we are using are better capable of dealing than with the one described above. In the mean time, let us follow the bending row of stars from An- tares toward the south and east. When you reach the star Mu (u), you are not unlikely to stop with an exclamation of admiration, for the glass will separate it into two stars that, shining side by side, seem trying to rival each other in bright- ness. But the next star below yw, marked Zeta (¢), is even more beautiful. It also separates into two stars, one being reddish and the other bluish in color. The contrast in a clear night is very pleasing. But this is not all. Above the two stars you will notice a cu- rious nebulous speck. Now, if you have a powerful field-glass, here is an oppor- tunity to view one of the prettiest sights in the heavens. The field-glass not only makes the two stars appear brighter, and their colors more pronounced, but it shows a third, fainter star below them, making a small triangle, and brings other still fainter stars into sight, while the neb- ulous speck above turns into a charmingly beautiful little star-cluster, whose components are so close that their rays are inextricably mingled in a maze of light. This little cut is an attempt to represent the scene, but no engraving can reproduce the life and sparkle of it. ZETA SCORPIONIS. , THE STARS OF SUMMER. 37 Following the bend of the Scorpion’s tail upward, we come to the pair of stars in the sting. These, of course, are thrown wide apart by the opera-glass. Then let us sweep off to the eastward a little way and find the cluster known as 7M. You will see it marked on the map. Above it, and near enough to be included in the same field of view, is 6 M., a smaller cluster. Both of these have a sparkling appearance with an opera-glass, and by close attention some of the sepa- rate stars in 7 M. may be detected. With a field-glass these clusters become much more striking and starry looking, and the curious radiated structure of 7 M. comes out. In looking at such objects we can not too often recall to our minds the significance of what we see—that these glim- mering specks are the lights in the windows of the universe which carry to us, across inconceivable tracts of space, the assurance that we and our little system are not alone in the heavens ; that all around us, and even on the very confines of immensity, Nature is busy, as she is here, and the laws of light, heat, gravitation (and why not of life?), are in full activity. The clusters we have just been looking at lie on the bor- ders of Scorpio and Sagittarius. Let us cross over into the latter constellation, which commemorates the centaur Chiron. We are now in another, and even a richer, region of won- ders. The Milky-Way, streaming down out of the north- east, pours, in a luminous flood, through Sagittarius, inun- dating that whole region of the heavens with seeming deeps and shallows, and finally bursting the barriers of the horizon disappears, only to glow with redoubled splendor in the southern hemisphere. The stars Zeta (f), Tau (7), Sigma (co), Phi (¢), Lambda (A), and Mu (yz) indicate the outlines of a fizure sometimes called the Milk-Dipper, which is very evi- dent when the eye has once recognized it. On either side of the upturned handle of this dipper-like figure lie some of the most interesting objects in the sky. Let us take the star p 38 ASTRONOMY WITH AN OPERA-GLASS. for a starting-point. Sweep downward and to the right a little way, and you will be startled by a most singular phenomenon that has suddenly made its appearance in the field of view of your glass. You may, perhaps, be tempted to congratulate yourself on having got ahead of all the astronomers, and dis- covered a comet. It is really a combination of a star-cluster with a nebula, and is known as8 M. Sir John Herschel has described the ‘‘nebulous folds and masses” and dark oval gaps which he saw in this nebula with his large telescope at the Cape of Good Hope. But no telescope is needed to make it appear a wonderful object ; an opera-glass suffices for that, — and a field-glass reveals still more of its marvelous structure. - The reader will recollect that we found the summer sol- stice close to a wonderful star-swarm in the feet of Gemini. Singularly enough the winter solstice is also near a star-clus- ter. It is to be found near a line drawn from 8 M. to the star w Sagittarii, and about one third of the way from the cluster to the star. There is another less conspicuous star-cluster — still closer to the solstitial point here, for this part of the heavens teems with such aggregations. On the opposite side of the star ~—that is to say, above and a little to the left—is an entirely different but almost equally attractive spectacle, the swarm of stars called 24 M. Here, again, the field-glass easily shows its superiority over the opera-glass, for magnifying power is needed to bring out the innumerable little twinklers of which the cluster is com- posed. But, whether you use an opera-glass or a field-glass, do not fail to gaze long and steadily at this island of stars, for much of its beauty becomes evident only after the eye has accustomed itself to disentangle the glimmering rays with which the whole field of view is filled. Try the method of averted vision, and hundreds of the finest conceivable points of light will seem to spring into view out of the depths of the sky. The necessity of a perfectly clear night, and the ab- sence of moonlight, can not be too much insisted upon for THE STARS OF SUMMER. 39 observations such as these. Everybody knows how the moon- light blots out the smaller stars. A slight haziness, or smoke, in the air produces a similar effect. It is as important to the observer with an opera-glass to have a transparent atmos- phere as it is to one who would use a telescope; but, fortu- nately, the work of the former is not so much interfered with by currents of air. Always avoid the neighborhood of any bright light. Electric lights in particular are an abomination to star-gazers. The cloud of stars we have just been looking at isin a very rich region of the Milky-Way, in the little modern con- stellation called ‘‘Sobieski’s Shield,” which we have not named upon our map. Sweeping slowly upward from 24 M. a little way with the field-glass, we will pass in succession over three nebulous-looking spots. The second of these, counting upward, is the famous Horseshoe nebula. Its won- ders are beyond the reach of our instrument, but its place may be recognized. Look carefully all around this region, and you will perceive that the old gods, who traveled this road (the Milky-Way was sometimes called the pathway of the gods), trod upon golden sands. Off a little way to the east you will find the rich cluster called 25 M. But do not imagine the thousands of stars that your opera-glass or field- glass reveals comprise all the riches of this Golconda of the heavens. You might ply the powers of the greatest telescope in a vain attempt to exhaust its wealth. As a hint of the wonders that lie hidden here, let me quote Father Secchi’s description of a starry spot in this same neighborhood, viewed with the great telescope at Rome. After telling of ‘‘ beds of Stars superposed upon one another,” and of the wonderful geometrical arrangement of the larger stars visible in the field, he adds: ‘*The greater number are arranged in spiral arcs, in which one can count as many as ten or twelve stars of the ninth to the tenth magnitude following one another in a curve, like 40 ASTRONOMY WITH AN OPERA-GLASS. beads upon a string. Sometimes they form rays which seem to diverge from a common focus, and, what is very singular, one usually finds, either at the center of the rays, or at the beginning of the curve, a more brilliant star of a red color, which seems to lead the march. It is impossible to believe that such an arrangement can be accidental.” The reader will recall the somewhat similar description that Admiral Smyth and Mr. Webb have given of a star-clus- ter in Gemini (see Chapter I). The milky look of the background of the Galaxy is, of course, caused by the intermingled radiations of inconceiv- ably minute and inconceivably numerous stars, thousands of which become separately visible, the number thus distin- guishable varying with the size of the instrument. But the most powerful telescope yet placed in human hands can not sound these starry deeps to the bottom. The evidence given by Prof. Holden, the Director of the Lick Observatory, on this point is very interesting. Speaking of the performance of the gigantic telescope on Mount Hamilton, thirty-six inches in aperture, he says: ‘“The Milky-Way is a wonderful sight, and I have been much interested to see that there is, even with our superla- tive power, no final resolution of its finer parts into stars. There is always the background of unresolved nebulosity on which hundreds and thousands of stars are studded—each a bright, sharp, separate point.” The groups of stars forming the eastern half of the con- stellation of Sagittarius are worth sweeping over with the glass, as a number of pretty pairs may be found there. Sagittarius stands in the old star-maps as a centaur, half- horse-half-man, facing the west, with drawn bow, and arrow pointed at the Scorpion. | Next let us pass to the double constellation adjoining Scorpio and Sagittarius on the north—Ophiuchus and the Serpent. These constellations, as our map shows, are curi- THE STARS OF SUMMER. 41 ously intermixed. The imagination of the old star-gazers, who named them, saw here the figure of a giant grasping a writh- IIERCULES 160% Oo 925 OPHIUCHUS *« 0 Map 9. ing serpent with his hands. The head of the serpent is under the Northern Crown, and its tail ends over the star- gemmed region that we have just described, called ‘‘Sobies- kis Shield.” Ophiuchus stands, as figured in Flamsteed’s ‘¢ Atlas,’ upon the back of the Scorpion, holding the serpent with one hand below the neck, this hand being indicated by the pair of stars marked Epsilon (e) and Delta (6), and with the other near the tail. The stars Tau (7) and Nu (v) indicate the second hand. The giant’s face is toward the observer, A 49 ASTRONOMY WITH AN OPERA-GLASS. and the star Alpha (a), also called Ras Alhague, shines in his forehead, while Beta (8) and Gamma (vy) mark his right shoulder. Ophiuchus has been held to represent the famous physician A‘dsculapius. One may well repress the tendency to smile at these fanciful legends when he reflects upon their antiquity. There is no doubt that this double constellation is at least three thousand years old—that is to say, for thirty centuries the imagination of men has continued to shape these stars into the figures of a gigantic man struggling with a huge serpent. If it possesses no other interest, then it at least has that which attaches to all things ancient. Like many other of the constellations it has proved longer-lived than the mightiest nations. While Greece fiourished and decayed, while Rome rose and fell, while the scepter of civilization has passed from race to race, these starry creations of fancy have shone on unchanged. The mind that would ignore them now deserves compassion. 7 The reader will observe a little circle in the map, and near it the figures 1604. This indicates the spot where one of the most famous temporary stars on record appeared in the year - 1604. At first it was far brighter than any other star in the heavens ; but it quickly faded, and in a little over a year dis- appeared. It is particularly interesting, because Kepler—the quaintest, and not far from the greatest, figure in astronomi- cal history—wrote a curious book about it. Some of the philosophers of the day argued that the sudden outburst of the wonderful star was caused by the chance meeting of atoms. Kepler’s reply was characteristic, as well as amusing: ‘*T will tell those disputants, my opponents, not my own opinion, but my wife’s. Yesterday, when I was weary with writing, my mind being quite dusty with considering these atoms, I was called to supper, and a salad I had asked for was set before me. ‘It seems, then,’ said I, aloud, ‘that if pewter dishes, leaves of lettuce, grains of salt, drops of water, vinegar and oil. and slices of egg, had been flying about in THE STARS OF SUMMER. 43 the air from all eternity, it might at last happen by chance that there would come a salad.’ ‘ Yes,’ says my wife, ‘but not so nice and well-dressed as this of mine is.’ ”’ ‘While there are no objects of special interest for the ob- server with an opera-glass in Ophiuchus, he will find it worth while to sweep over it for what he may pick up, and, in par- ticular, he should look at the group of stars southeast of @ and y. These stars have been shaped into a little modern asterism called Taurus Poniatowskii, and it will be noticed that five of them mark the outlines of a letter V, resembling the well-known figure of the Hyades. Also look at the stars in the head of Serpens, several of which form a figure like a letter X._ A little west of Theta (0), - in the tail of Serpens, is a beautiful swarm. of little stars, upon which a field-glass may be used with advantage. The star @ is itself a charming double, just within the separating power of a very powerful field-glass under favorable circum- stances, the component stars being only about.one third of a minute apart. Do not fail to notice the remarkable subdivisions of the Milky-Way in this neighborhood. Its current seems divided into numerous channels and bays, interspersed with gaps that might be likened to islands, and the star @ appears to be. situated upon one of these islands of the galaxy. This com- plicated structure of the Milky-Way extends downward to the horizon, and upward through the constellation Cygnus, and of its phenomenal appearance in that region we shall have more to say further on. Directly north of Ophiuchus is the constellation Hercules, interesting as occupying that part of the heavens toward which the proper motion of the sun is bearing the earth and its fellow-planets, at the rate, probably, of not less than 160,- 000,000 miles in a year—a stupendous voyage through space, of whose destination we are as ignorant as the crew of a ship sailing under sealed orders, and, like whom, we must depend 44 ASTRONOMY WITH AN OPERA-GLASS. upon such inferences as we can draw from courses and dis- tances, for no other information comes to us from the flag- ship of our squadron. In the accompanying map we have represented the beau- tiful constellations Lyra and the Northern Crown, lying on BOOTES > OPHIUCHUS Map 10. either side of Hercules. The reader should note that the point overhead in this map is not far from the star Eta (7) in Hercules. The bottom of the map is toward the south, the right-hand side is west, and the left-hand side east. It 1s im- portant to keep these directions in mind, in comparing the map with the sky. For instance, the observer must not ex- pect to look into the south and see Hercules half-way up the sky, with Lyra a little east of it; he must look for Hercules THE STARS OF SUMMER. 45 nearly overhead, and Lyra a little east of the zenith. The same precautions are not necessary in using the maps of Scorpio, Sagittarius, and Ophiuchus, because those constella- tions are nearer the horizon, and so the observer does not have to imagine the map as being suspended over his head. The name Hercules sufficiently indicates the mythological origin of the constellation, and yet the Greeks did not know it by that name, for Aratus calls it ‘‘ the Phantom whose name none can tell.” The Northern Crown, according to fable, was the celebrated crown of Ariadne, and Lyra was the harp of Orpheus himself, with whose sweet music he charmed the hosts of Hades, and persuaded Pluto to yield up to him his lost Eurydice. With the aid of the map you will be able to recognize the principal stars and star-groups in Hercules, and will find many interesting combinations of stars for yourself. An object of special interest is the celebrated star-cluster 13 M. You will find it on the map between the stars Eta (7) and Zeta (€). While an opera-glass will only show it as a faint and minute speck, lying nearly between two little stars, it is nevertheless well worth looking for, on account of the great renown of this wonderful congregation of stars. Sir William Herschel computed the number of stars contained in it as about fourteen thousand. It is roughly spherical in shape, though there are many straggling stars around it evidently connected with the cluster. In short, it is a ball of suns. The reader should not mistake what that implies, however. These suns, though truly solar bodies, are probably very much smaller than our sun. Mr. Gore has computed their average diameter to be forty-five thousand miles, and the distance separating each from the next to be 9,000,000,000 miles. It may not be uninteresting to inquire what would be the appearance of the sky to dwellers within such a sys- tem of suns. Adopting Mr. Gore’s estimates, and supposing 9,000,000,000 miles to be very nearly the uniform distance 46 ASTRONOMY WITH AN OPERA-GLASS. apart of the stars in the cluster, and forty-five thousand miles their uniform diameter, then, starting with a single star in the center, their arrangement might be approximately in concentric spherical shells, situated about 9,000,000,000 miles apart. The first shell, counting outward from the center, would contain a dozen stars, each of which, as seen by an observer stationed upon a planet at the center of the cluster, would shine eleven hundred times as bright as Sirius appears tous. The number of the stars in each shell would increase as they receded from the center in proportion to the squares of the radii of the successive shells, while their luminosity, as seen from the center, would vary inversely as those squares. Still, the outermost stars—the total number being limited to fourteen or fifteen thousand—would appear to our observer at the center of the system about five times as brill- - jant as Sirius. It is clear, then, that he would be dwelling in a sort of perpetual daylight. His planet might receive from the par- ticular sun around which it revolved as brilliant a daylight as our sun gives to us, but let us see what would be the illumi- nation of its night side. Adopting Zodllner’s estimate of the light of the sun as 618,000 times as great as that of the full moon, and choosing among the various estimates of the light of Sirius as compared with the sun gypggaaa07 AS probably the nearest the truth, we find that the moon sends us about sixty-five hundred times as much light as Sirius does. Now, since the dozen stars nearest the center of the cluster would each appear to our observer eleven hundred times as bright as Sirius, all of them together would give a little more than twice as much light as the full moon sheds upon the earth. But as only half the stars in the cluster would be above the horizon at once we must diminish this estimate by one half, in order to obtain the amount of light that our supposititious planet would receive on its night side from the nearest stars in the cluster. And since the number of these stars increases THE STARS OF SUMMER. 47 with their distance from the center in the same ratio as their light diminishes, it follows that the total light received from the cluster would exceed that received from the dozen nearest stars as many times as there were spherical shells in the clus- ter. This would be about fifteen times, and accordingly all the stars together would shed, at the center, some thirty times as much light as that of the moon. Dividing this again by two, because only half of the stars could be seen at once, we find that the night side of our observer’s planet would be illu- minated with fifteen times as much light as the full moon sheds upon the earth. It is evident, too, that our observer would enjoy the spec- tacle of a starry firmament incomparably more splendid than that which we behold. Only about three thousand stars are visible to our unassisted eyes at once on any clear night, and of those only a few are conspicuous, and two thirds are so faint that they require some attention in order to be distin- guished. But the spectator at the center of the Hercules cluster would behold some seven thousand stars at once, the faintest of which would be five times as brilliant as the bright- est star in our sky, while the brighter ones would blaze like nearing suns. One effect of this flood of starlight would be to shut out from our observer’s eyes all the stars of the out- side universe. They would be effaced in the blaze of his sky, and he would be, in a manner, shut up within his own little star-system, knowing nothing of the greater universe beyond, in which we behold his multitude of luminaries, diminished and blended by distance into a faintly shining speck, floating like a silvery mote in a sunbeam. : If our observer’s planet, instead of being situated in the center of the cluster, circled around one of the stars at the outer edge of it, the appearance of his sky would be, in some respects, still more wonderful, the precise phenomena de- pending upon the position of the planet’s orbit and the sta- tion of the observer. Less than half of his sky would be 48 ASTRONOMY WITH AN OPERA-GLASS. filled, at any time, by the stars of the cluster, the other half opening upon outer space and appearing by comparison almost starless—a vast, cavernous expanse, with a few faint glimmerings out of its gloomy depths. The plane of the orbit of his planet being supposed to pass through the center of the spherical system, our observer would, during his year, behold the night at one season blazing with the splendors of the clustered suns, and at another emptied of brilliant orbs and faintly lighted with the soft glow of the Milky-Way and the feeble flickering of distant stars, scattered over the dark vault. The position of the orbit, and the inclination of the planet’s axis might be such that the glories of the cluster would not be visible from one of its hemispheres, necessitat- ing a journey to the other side of the globe to behold them.* Of course, it is not to be assumed that the arrange- ment of the stars in the cluster actually is exactly that which we have imagined. Still, whatever the arrangement, so long as the cluster is practically spherical, and the stars com- posing it are of nearly uniform size and situated at nearly uniform distances, the phenomena we have described would fairly represent the appearances presented to inhabitants of worlds situated in such a system. As to the possibility of the existence of such worlds and inhabitants, everybody must draw his own conclusions. Astronomy, as a science, is silent upon that question. But there shine the congre- gated stars, mingling their rays in a message of light, that comes to us across the gulf, proclaiming their brotherhood with our own glorious sun. Mathematicians can not unravel the interlocking intricacies of their orbits, and some would, perhaps a priori, have said that such a system was impossi- ble, but the telescope has revealed them, and there they are! What purposes they subserve 1, the economy of the uni- verse, who shall declare ? * A similar calculation of the internal appearances of the Hercules cluster, which I made, was published in 1887 in the ‘‘ New York Sun.” THE STARS. OF SUMMER. 49 If you have a field-glass, by all means try it upon 13 M. It will give you a more satisfactory view than an opera-glass is capable of doing, and will magnify the cluster so that there can be no possibility of mistaking it for a star. Compare this compact cluster, which only a powerful telescope can par- tially resolve into its component stars, with 7 M. and 24 M., described before, in order to comprehend the wide variety in the structure of these aggregations of stars. The Northern Crown, although a strikingly beautiful constellation to the naked eye, offers few attractions to the opera-glass. Let us turn, then, to Lyra. I have never been able to make up my mind which of three great stars is en- titled to precedence—Vega, the leading brilliant of Lyra, Arcturus in Bootes, or Capella in Auriga. They are the three leaders of the northern firmament, but which of them should be called the chief, is very hard to say. At any rate, Vega would probably be generally regarded as the most beautiful, on account of the delicate bluish tinge in its light, especially when viewed with a glass. There is no possibility of mistaking this star because of its surpassing brilliancy. Two faint stars close to Vega on the east make a beautiful little triangle with it, and thus form a further means of recog- nition, if any were needed. Your opera-glass will show that the floor of heaven is powdered with stars, fine as the dust of a diamond, all around the neighborhood of Vega, and the longer you gaze the more of these diminutive twinklers you - will discover. Now direct your glass to the northernmost of the two lit- tle stars near Vega, the one marked Epsilon (e) in the map. You will perceive that it is composed of two stars of almost equal magnitude. If you had a telescope of considerable power, you would find that each of these stars is in turn doable. In other words, this wonderful star which appears single to the unassisted eye, is in reality quadruple, and there is reason to think that the four stars composing it are 50 ASTRONOMY WITH AN OPERA-GLASS. connected in pairs, the members of each pair revolving around their common center while the two pairs in turn cir- oo URSA MA oe ¢\ aie wh BOs Za) re) 5) > oO joe a) = Map 11. cle around a center common to all. With a field-glass you will be able to see that the other star near Vega, Zeta (€), is also double, the distance between its components being three quarters of a minute, while the two stars in e are a little less than 33’ apart. The star Beta (8) is remarkably variable in brightness. You may watch these variations, which run through a regular period of about 12 days, 21% hours, for yourself. Between Beta and Gamma (y) lies the beautiful Ring nebula, but it is hopelessly beyond the reach of the optical means we are employing. 3 THE STARS OF SUMMER. 51 Let us turn next to the stars in the west. In consulting the accompanying map of Virgo and Bodtes (Map No. 11), the observer is supposed to face the southwest, at the hours and dates mentioned above as those to which the circular map corresponds. He will then see the bright star Spica in Virgo not far above the horizon, while Arcturus will be half- way up the sky, and the Northern Crown will be near the zenith. The constellation Virgo is an interesting one in mytho- logical story. Aratus tells us that the Virgin’s home was once on earth, where she bore the name of Justice, and in the golden age all men obeyed her. In the silver age her visits to men became less frequent, ‘‘no longer finding the spirits of former days’’; and, finally, when the brazen age came with the clangor of war: ‘* Justice, loathing that race of men, Winged her flight to heaven ; and fixed Her station in that region — Where still by night is seen The Virgin goddess near to bright Bodtes.” The chief star of Virgo, Spica, is remarkable for its pure white light. To my eye there is no conspicuous star in the sky equal to it in this respect, and it gains in beauty when viewed with a glass. With the aid of the map the reader will find the celebrated binary star Gamma (y) Virginis, although he will not be able to separate its components without a tele- scope. It isa curious fact that the star Epsilon (e) in Virgo has for many ages been known as the Grape-Gatherer. It has borne this name in Greek, in Latin, in Persian, and in Arabic, the origin of the appellation undoubtedly being that it was observed to rise just before the sun in the season of the vintage. It will be observed that the stars e, 6, y, 7, and 8, mark two sides of a quadrilateral figure of which the oppo- site corner is indicated by Denebola in the tail of Leo. Within this quadrilateral lies the marvelous [Field of the U. OF ILL. LIB. 52 ASTRONOMY WITH AN OPERA-@GLASS. Nebule, a region where with adequate optical power one may find hundreds of these strange objects thronging to- gether, a very storehouse of the germs of suns and worlds. Unfortunately, these nebule are far beyond the reach of an opera-glass, but it is worth while to know where this curious region is, even if we can not behold the wonders it contains. The stars Omicron (0), Pi (7), etc., forming a little group, mark the head of Virgo. The autumnal equinox, or the place where the sun crosses the equator of the heavens on his southerly journey ,about the 2ist of September, is situated nearly between the stars 7 and 8 Virginis, a little below the line joining them, and somewhat nearer to 7, Both » and ¢ Virginis are almost exactly upon the equator of the heavens. The constellation Libra, lying between Virgo and Scorpio, does not contain much to attract our attention. Its two chief stars, a and 8, may be readily recognized west of and above the head of Scorpio. The upper one of the two, #, has a singular greenish tint, and the lower one, a, is a very pretty double for an opera-glass. The constellation of Libra appears to have been of later date than the other eleven members of the zodiacal circle. Its two chief stars at one time marked the extended claws of Scorpio, which were afterward cut off (perhaps the monster proved too horrible even for its inventors) to form Libra. As its name signifies, Libra represents a balance, and this fact seems to refer the invention of the constellation back to at least three hundred years before Christ, when the au- tumnal equinox occurred at the moment when the sun was just crossing the western border of the constellation. The equality of the days and nights at that, season. readily suggests the idea of a balance. Milton, in ‘‘ Paradise Lost,” suggests another origin for the constellation of the Balance in the account of Gabriel’s discovery of Satan in paradise : THE STARS OF SUMMER. 53 ‘“ , . . Now dreadful deeds Might have ensued, nor only paradise In this commotion, but the starry cope Of heaven, perhaps, or all the elements At least had gone to wrack, disturbed and torn With violence of this conflict, had not soon The Eternal, to prevent sueh horrid fray, Hung forth in heaven his golden scales, yet seen Betwixt Astrea and the Scorpion sign.” Just north of Virgo’s head will be seen the glimmering of Berenice’s Hair. This little constellation was included among those described in the chapter on ‘‘The Stars of Spring,” but it is worth looking at again in - the early summer, on moonless nights, when the singular arrangement of the brighter members of the cluster at once strikes the eye. Bootes, whose leading brilliant, Arcturus, occupies the center of our map, also possesses a curious mythi- cal history. It is called by the Greeks the Bear-Driver, | because it seems continually to chase Ursa Major, the Great Bear, in his path around the pole. The story is that Bootes was the son of the nymph Calisto, whom Juno, in’ one of her customary fits of jealousy, turned into a bear. Bodtes, who had become a famous hunter, one day roused a bear from her lair, and, not knowing that it was his mother, was about to kill her, when Jupiter came to the rescue and snatched them both up into the sky, where they have shone ever since. Lucan refers to this story when, describing Brutus’s visit to Cato at night, he fixes the time by the position of these con- stellations in the heavens: BERENICE’S HAIR. 54 ASTRONOMY WITH AN OPERA-GLASS. ~ “°*Twas when the solemn dead of night came on, When bright Calisto, with her shining son, Now half the circle round the pole had run.” Bootes is not specially interesting for our purposes, ex- cept for the splendor of Arcturus. This star has possessed a peculiar charm for me ever since boyhood, when, having read a description of it in an old treatise on Uranography, I felt an eager desire to see it. As my search for it chanced to be- gin at a season when Arcturus did not rise till after a boy’s bed-time, I was for a long time disappointed, and I shall never forget the start of surprise -and almost of awe with which I finally caught sight of it, one spring evening, shoot- ing its flaming rays through the boughs of an apple-orchard, like a star on fire. When near the horizon, Arcturus has a remarkably red- dish color; but, after it has attained a high elevation in the sky, it appears rather a deep yellow than red. There is a scattered cluster of small stars surrounding Arcturus, form- ing an admirable spectacle with an opera-glass on a clear night. To see these stars well, the glass should be slowly moved about. Many of them are hidden by the glare of Arc- turus. The little group of stars near the end of the handle of the Great Dipper, or, what is the same thing, the tail of the Great Bear, marks the upraised hand of Bodtes. Be- tween Berenice’s Hair and the tail of the Bear you will seea small constellation called Canes Venatici, the Hunting-Dogs. On the old star-maps Bootes is represented as holding these dogs with a leash, while they are straining in chase of the Bear. You will find some pretty groupings of stars in this constellation. : And now we will turn to the east. Our next map shows Cygnus, a constellation especially remarkable for the large and striking figure that it contains, called the Northern Cross, Aquila the Eagle, the Dolphin, and the little asterisms Sagitta and Vulpecula. In consulting the map, the observer THE STARS OF SUMMER. 5d is supposed to face toward the east. In Aquila the curious arrangement of two stars on either side of the chief star of the constellation, called Altair, at once attracts the eye. Within a circle including the two attendants of Altair you will probably be able to see with the naked eye only two or three stars in addition to the three large ones. Now turn your glass upon the same spot, and you will see eight or ten times as many stars, and with a field-glass still more can be seen. Watch the star marked Eta (), and you will find that its light is variable, being sometimes more than twice as bright as at other times. Its changes are periodical, and oc- cupy a little over a week. The Eagle is fabled to have been the bird that Jupiter kept beside his throne. A constellation called Antinous, in- vented by Tycho Brahe, is represented on some maps as oc- cupying the lower portion of the space given to Aquila. The Dolphin is an interesting little constellation, and the ancients said it represented the very animal on whose back the famous musician Arion rode through the sea after his es- cape from the sailors who tried to murder him. But some modern has dubbed it with the less romantic name of Job’s Coffin, by which it is sometimes called. It presents a very pretty sight to the opera-glass. Cygnus, the swan, is a constellation whose mythological history is not specially interesting, although, as remarked above, it contains one of the most clearly marked figures to be found among the stars, the famous Northern Cross. The outlines of this cross are marked with great distinctness by the stars Alpha (a), Epsilon (e), Gamma (¥), Delta (6), and Beta (8), together -with some fainter stars lying along the main beam of the cross between 8 andy. The star 8, also called Albireo, is one of the most beautiful double stars in the heavens. The components are sharply contrasted in color, the larger star being golden-yellow, while the smaller one is a deep, rich blue. With a field-glass of 1°6-inch aperture 56 ASTRONOMY WITH AN OPERA-GLASS. and magnifying seven times I have sometimes been able to divide this pair, and to recognize the blue color of the smaller star. It will be found a severe test for such a glass. CYGNUS oe “PEGASUS * Map 12. About half-way from Albireo to the two stars ¢€ and e in Aquila is a very curious little group, consisting of six or seven stars in a straight row, with a garland of other stars hanging from the center. ‘Po see it best, take a field-glass, » although an opera-glass shows it. I have indicated the place of the celebrated star 61 Cygni in the map, because of the interest attaching to it as the near- est to us, so far as we know, of all the stars in the northern THE STARS OF SUMMER. age hemisphere, and with one exception the nearest star in all the heavens. Yet it is very faint, and the fact that so incon- spicuous a star should be nearer than such brilliants as Vega and Arcturus shows how wide is the range of magnitude among the suns that light the universe. The actual distance of 61 Cygni is something like 650,000 times as great as the distance from the earth to the sun. } The star Omicron (0) is very interesting with an opera- glass. The naked eye sees a little star near it. The glass throws them wide apart, and divides o itself into two stars. Now, a field-glass, if of sufficient power, will divide the larger of these stars again into two—a fine test. Sweep around a and y for the splendid star-fields that abound in this neighborhood ; also around the upper part of the figure of the cross. We are here in one of the richest parts of the Milky-Way. Between the stars a, y, ¢, is the strange dark gap in the galaxy called the Coal-Sack, a sort of hole in the starry heavens. Although it is not entirely empty of stars, its blackness is striking in contrast with the brilliancy of the Milky-Way in this neighborhood. The divergent streams of the great river of light in this region present a very remarkable appearance. Finally, we come to the great dragon of the sky. In using the map of Draco and the neighboring constellations, the reader is supposed to face the north. The center of the up- per edge of the map is directly over the observer’s head. One of the stories told of this large constellation is that it repre- sents a dragon that had the temerity to war against Minerva. The goddess ‘‘seized it in her hand, and hurled it, twisted as it was, into the heavens round the axis of the world, be- fore it had time to unwind its contortions.” Others say it is the dragon that guarded the golden apples in the Garden of the Hesperides, and that was slain by the redoubtable Her- cules. At any rate, it is plainly a monster of the first magni- tude. The stars B, y, &, v, and w represent its head, while its 5 58 ASTRONOMY WITH AN OPERA-GLASS. body runs trailing along, first sweeping in a long curve to- ward Cepheus, and then bending around and passing between -BOOTES Rs MINOR * POLE ap ot STAR eee % ye pate 2 * * * CAMELOPARD .. Map 18. the two bears. Try v with your opera-glass, and if you suc- ceed in seeing it double you may congratulate yourself on your keen sight. The distance between the stars is about Ll’. Notice the contrasted colors of y and £8, the former being a rich orange and the latter white. As you sweep along the winding way that Draco follows, you will run across many striking fields of stars, although the heavens are not as rich here as in the splendid regions that we have just left. You will also find that Cepheus, although not an attractive con- THE STARS OF SUMMER. 59 stellation to the naked eye, is worth some attention with an opera-glass. The head and upper part of the body of Ce- pheus are plunged in the stream of the Milky Way, while his feet are directed toward the pole of the heavens, upon which he is pictured as standing. Cepheus, however, sinks into in- significance in comparison with its neighbor Cassiopeia, but that constellation belongs rather to the autumn sky, and we shall pass it by here. CHAPTER III. . THE STARS OF AUTUMN. In the ‘‘ Fifth Evening’’ of that delightful, old, out-of- date book of Fontenelle’s, on the ‘‘ Plurality of Worlds,’ the Astronomer and the Marchioness, who have been making a wonderful pilgrimage through the heavens during their even- ~ ing strolls in the park, come at last to the starry systems be- yond the ‘‘ solar vortex,” and the Marchioness experiences a lively impatience to know what the fixed stars will turn out to be, for the Astronomer has sharpened her appetite for marvels. ‘‘Tell me,”’ says she, eagerly, ‘‘are they, too, inhabited like the planets, or are they not peopled? In short, what can we make of them?” The Astronomer answers his charming questioner, as we should do to-day, that the fixed stars are so many suns. And he adds to this information a great deal of entertaining talk about the planets that may be supposed to circle around these distant suns, interspersing his conversation with explanations of ‘‘ vortexes,” and many quaint conceits, in which he is helped out by the ready wit of the Marchioness. Finally, the impressionable mind of the lady is over- whelmed by the grandeur of the scenes that the Astronomer _ opens to her view, her head swims, infinity oppresses her, and she cries for mercy. ‘You show me,” she exclaims, ‘‘a perspective so inter- minably long that the eye can not see the end of it. I see nlainly the inhabitants of the earth; then you cause me to THE STARS OF AUTUMN. 61 perceive those of the moon and of the other planets belonging to our vortex (system), quite clearly, yet not so distinctly as those of the earth. After them come the inhabitants of plan- ets in the other vortexes. I confess, they seem to me hidden deep in the background, and, however hard I try, I can bare- ly glimpse them at all. In truth, are they not almost anni- hilated by the very expression which you are obliged to use in speaking of them? You have to call them inhabitants of one of the planets contained in one out of the infinity of vor- texes. Surely we ourselves, to whom the same expression applies, are almost lost among so many millions of worlds. For my part, the earth begins to appear so frightfully little to me that henceforth I shall hardly consider any object wor- thy of eager pursuit. Assuredly, people who seek so earnest- ly their own aggrandizement, who lay schemes upon schemes, and give themselves so much trouble, know nothing of the vortexes! Jam sure my increase of knowledge will redound to the credit of my idleness, and when people reproach me with indolence I shall reply: ‘Ah! if you but knew the his- tory of the fixed stars!’ ” It is certainly true that a contemplation of the unthink- able vastness of the universe, in the midst of which we dwell upon a speck illuminated by a spark, is calculated to make all terrestrial affairs appear contemptibly insignificant. We can not wonder that men for ages regarded the earth as the cen- ter, and the heavens with their lights as tributary to it, for to have thought otherwise, in those times, would have been to see things from the point of view of a superior intelligence. It has taken a vast amount of experience and knowledge to convince men of the parvitude of themselves and their belong- ings. So, in all ages they have applied a terrestrial measure to the universe, and imagined they could behold human affairs reflected in the heavens and human interests setting the gods together by the ears. This is clearly shown in the story of the constellations, “LSVa 62 ASTRONOMY WITH AN OPERA-GLASS. The tremendous truth that on a starry night we look, in every direction, into an almost endless vista of suns beyond © oO <@ ioe oO * ‘ \S Piscis RUS TAAL SOUTH. Map. 14. suns and systems upon systems, was too overwhelming for comprehension by the inventors of the constellations. So they amused themselves, like imaginative children, as they were, by tracing the outlines of men and beasts formed by those pretty lights, the stars. They turned the starry heav- ens into a scroll filled with pictured stories of mythology. Wars tl. THE STARS OF AUTUMN. 68 Four of the constellations with which we are going to deal in this chapter are particularly interesting on this account. They preserve in the stars, more lasting than parchment or stone, one of the oldest and most pleasing of all the romantic stories that have amused and inspired the minds of men—the story of Perseus and Andromeda—a better story than any that modern novelists have invented. The four constellations to which I refer bear the names of Andromeda, Perseus, Cas- siopeia, and Cepheus, and are sometimes called, collectively, the Royal Family. In the autumn they occupy a conspicu- ous position in the sky, forming a group that remains un- rivaled until the rising of Orion with his imperial cortege. The reader will find them in Map No. 14, occupying the northeastern quarter of the heavens. This map represents the visible heavens at about midnight on September 1st, ten o’clock Pp. M. on October Ist, and eight o’clock Pp. M. on November ist. At this time the constella- tions that were near the meridian in summer will be found sinking in the west, Hercules being low in the northwest, with the brilliant Lyra and the head of Draco suspended above it; Aquila, ‘‘the eagle of the winds,” soars high in the southwest ; while the Cross of Cygnus is just west of the zenith ; and Sagittarius, with its wealth of star-dust, is disap- pearing under the horizon in the southwest. Far down in the south the observer catches the gleam of a bright lone star of the first magnitude, though not one of the largest of that class. It is Fomalhaut, in the mouth of the Southern Fish, Piscis Australis. *« B * XK ( PISCIS AUSTRAUS SAGITTARIUS Map 15. THE STARS OF AUTUMN. 65 counts, though by no means a striking constellation to the unassisted eye. The stars Alpha (a), called Giedi, and Beta (8), called Dabih, will be readily recognized, and a keen eye will perceive that Alpha really consists of two stars. They are about six minutes of arc apart, and are of the third and the fourth magnitude respectively. These stars, which to the naked eye appear almost blended into one, really have no physical connection with each other, and are slowly drifting apart. The ancient astronomers make no mention of Giedi being composed of two stars, and the reason is plain, when it is known that in the time of Hipparchus, as Flammarion has pointed out, their distance apart was not more than two thirds as great as it is at present, so that the naked eye could not have detected the fact that there were two of them ; and if was not until the seventeenth century that they got far enough asunder to begin to be separated by eyes of unusual power. With an ordinary opera-glass they are thrown well apart, and present a very pretty sight. Consid- ering the manner in which these stars are separating, the fact that both of them have several faint companions, which our powerful telescopes reveal, becomes all the more inter- esting. A suggestion of Sir John Herschel, concerning one of these faint companions, that it shines by reflected light, adds to the interest, for if the suggestion is well founded the little star must, of course, be actually a planet, and granting that, then some of the other faint points of light seen there are probably planets too. It must be said that the proba- bilities are against Herschel’s suggestion. The faint stars more likely shine with their own light. Even so, however, these two systems, which apparently have met and are pass- ing one another, at a distance small as compared with the space that separates them from us, possess a peculiar interest, like two celestial fleets that have spoken one another in the midst of the ocean of space. The star Beta, or Dabih, is also a double star. The com- 66 ASTRONOMY WITH AN OPERA-GLASS. panion is of a beautiful blue color, generally described as ‘“sky-blue.” It is of the seventh magnitude, while the larger star is of magnitude three and a half. The latter is golden- yellow. The blue of the small star can be seen with either an opera- or a field-glass, but it requires careful looking and a clear and steady atmosphere. I recollect discovering the color of this star with a field-glass, and exclaiming to myself, ‘“Why, the little one is as blue as a bluebell!” before I knew that that was its hue as seen with a telescope. Trying my opera-glass upon it I found that the color was even more distinct, although the small star was then more or less en- veloped in the yellow rays of the large one. The distance between the two stars in Dabih is nearly the same as that between the components of e Lyre, and the comparative difficulty of separating them is an instructive example of the effect of a large star in concealing a small one close beside it. The two stars in e Lyre are of nearly equal brightness, and are very easily separated and distinguished, but in 8 Capricorni, or Dabih, one star is about twenty times as bright as the other, and consequently the fainter star is almost con- cealed in the glare of its more brilliant neighbor. With the most powerful glass at your disposal, sweep from the star Zeta (f) eastward a distance somewhat greater than that separating Alpha and Beta, and you will find a fifth-magnitude star beside a little nebulous spot. This is the cluster Known as 30 M, one of those sun-Swarms that over- whelm the mind of the contemplative observer with astonish- ment, and especially remarkable in this case for the apparent vacancy of the heavens immediately surrounding the cluster, as if all the stars in that neighborhood had been drawn into the great assemblage, leaving a void around it. Of course, with the instrument that our observer is supposed to be using, merely the existence of this solar throng can be detect- ed; but, if he sees that it is there, he may be led to provide himself with a telescope capable of revealing its glories. THE STARS OF AUTUMN. 6% Admiral Smyth remarks that, ‘‘although Capricorn is not a striking object, it has been the very pet of all constellations with astrologers,” and he quotes from an old almanac of the year 1386, that ‘‘whoso is borne in Capcorn schal be ryche and wel lufyd.’? The mythological account of the constella- tion is that it represents the goat into which Pan was turned in order to escape from the giant Typhon, who once on a time scared all the gods out of their wits, and caused them to change themselves into animals, even Jupiter assuming the form of aram. According to some authorities, Piscis Aus- tralis represents the fish into which Venus changed herself on that interesting occasion. Directly above Piscis Australis, and to the east or left of Capricorn, the map shows the constellation of Aquarius, or the Water-Bearer. Some say this commemorates Ganymede, the cup-bearer of the gods. It is represented in old star-maps by the figure of a young man pouring water from an urn. The star Alpha (a) marks his right shoulder, and Beta (8) his left, and Gamma (), Zeta (¢), Eta (7), and Pi (7) indicate his right hand and the urn. From this group a current of small stars will be recognized, sweeping downward with a curve toward the east, and ending at Fomalhaut; this represents the water poured from the urn, which the Southern Fish appears to be drinking. In fact, according to the pictures in the old maps, the fish succeeds in swallowing the stream completely, and it vanishes from the sky in the act of entering his distended mouth! It is worthy of remark that in Greek, Latin, and Arabic this constellation bears names all of which signify ‘a man pouring water.”’ The ancient Egyptians imagined that the setting of Aquarius caused the rising of the Nile, as he sank his huge urn in the river to fill it. Alpha Aquarii was called by the Arabs Sadalmelik, which is interpreted to mean the ‘‘ king’s lucky star,” but whether it proved itself a lucky star in war or in love, and what particular king enjoyed its benign influence and recorded his gratitude in its name, we 68 ASTRONOMY WITH AN OPERA-GLASS. are not informed. Thus, at every step, we find how shreds of history and bits of superstition are entangled among the stars. Surely, humanity has been reflected in the heavens as lastingly as it has impressed itself upon the earth. Starting from the group of stars just described as forming the Water-Bearer’s urn, follow with a glass the winding stream of small stars that represent the water. Several very pretty and striking assemblages of stars will be encountered in its course. The star Tau (7) is double and presents a beau- tiful contrast of color, one star being white and the other reddish-orange—two solar systems, it may be, apparently neighbors as seen from the earth, in one of which daylight is white and in the other red ! Point a good glass upon the star marked Nu (v), and you will see, somewhat less than a degree and 4 half to the west of it, what appears to be a faint star of between the seventh and eighth magnitudes. You will have to look sharp to see it. It is with your mind’s eye that you must gaze, in order to perceive the wonder here hidden in the depths of space. That faint speck is a nebula, unrivaled for interest by many of the larger and more conspicuous objects of that kind. Lord Rosse’s great telescope has shown that in form it re- sembles the planet Saturn; in other words, that it consists apparently of a ball surrounded by a ring. But the spectro- scope proves that it is a gaseous mass, and the micrometer— supposing its distance to be equal to that of the stars, and we have no reason to think it less—that it must be large enough to fill the whole space included within the orbit of. Neptune! Here, then, as has been said, we seem to behold a genesis in the heavens. If Laplace’s nebular hypothesis, or any of the modifications of that hypothesis, represents the process of formation of a solar system, then we may fairly conclude that such a process is now actually in operation in this nebula in Aquarius, where a vast ring of nebulous mat- ter appears to have separated off from the spherical mass THE STARS OF AUTUMN. 69 within it. This may not be the true explanation of what we see there, but, whatever the explanation is, there can be no question of the high significance of this nebula, whose shape proclaims unmistakably the operation of great metamorphic forces there. Of course, with his insignificant optical means, our observer can see nothing of the strange form of this object, the detection of which requires the aid of the most powerful telescopes, but it is much to know where that un- finished creation lies, and to see it, even though diminished by distance to a mere speck of light. Turn your glass upon the star shown in the map just above Mu (wv) and Epsilon (ce). You will find an attractive arrangement of small stars in its neighborhood. The star marked 104 is double to the naked eye, and the row of stars below it is well worth looking at. The star Delta (6) indi- cates the place where, in 1756, Tobias Mayer narrowly escaped making a discovery that would have anticipated that which a quarter of a century later made the name of Sir William Herschel world-renowned. The planet Uranus passed near Delta in 1756, and Tobias Mayer saw it, but it moved so slowly that he took it for a fixed star, never suspecting that his eyes had rested upon a member of the solar system whose existence was, up to that time, unknown to the inhabitants of Adam’s planet. Above Aquarius you will find the constellation Pegasus. It is conspicuously marked by four stars of about the second magnitude, which shine at the corners of a large square, called the Great Square of Pegasus. This figure is some fif- teen degrees square, and at once attracts the eye, there being few stars visible within the quadrilateral, and no large ones in the immediate neighborhood to distract attention from it. One of the four stars, however, as will be seen by consulting Map 15, does not belong to Pegasus, but to the constellation Andromeda. Mythologically, this constellation represents the celebrated winged horse of antiquity : %0 ASTRONOMY WITH AN OPERA-GLASS. ‘« Now heaven his further wandering flight confines, Where, splendid with his numerous stars, he shines.” The star Alpha (a) is called Markab; Beta (8) is Scheat, and Gamma (fy) is Algenib; the fourth star in the square, belonging to Andromeda, is called Alpheratz. Although Pegasus presents a striking appearance to the unassisted eye, on account of its great square, it contains little to attract the observer with an opera-glass. It will prove interesting, how- ever, to sweep with the glass carefully over the space within the square, which is comparatively barren to the naked eye, but in which many small stars will be revealed, of whose ex- istence the naked-eye observer would be unaware. The star marked Pi (7) is an interesting double, which can be sepa- rated by a good eye without artificial aid, and which, with an opera-glass, presents a fine appearance. And now we come to Map No. 16, representing the con- stellations Cetus, Pisces, Aries, and the Triangles. In con- sulting it the observer is supposed to face the southeast. Cetus is a very large constellation, and from the peculiar con- formation of its principal stars it can be readily recognized. The head is to the east, the star Alpha (a), called Menkar, being in the nose of this imaginary inhabitant of the sky- depths. The constellation is supposed to represent the mon- ster that, according to fable, was sent by Neptune to devour the fair Andromeda, but whose bloodthirsty design was hap- pily and gallantly frustrated by Perseus, as we shall learn from starry mythology further on. Although bearing the name Cetus, the Whale, the pict- ures of the constellation in the old maps do not present us with the form of a whale, but that of a most extraordinary scaly creature with enormous jaws filled with large teeth, a forked tongue, fore-paws armed with gigantic claws, and a long, crooked, and dangerous-looking tail. Indeed, Aratus does not call it a ‘‘ whale,” but a ‘‘sea-monster,” and Dr. Seiss would have us believe that it was intended to represent THE STARS OF AUTUMN. 71 the leviathan, whose terrible prowess is celebrated in the book of Job. By far the most interesting object in Cetus is the star Mira. This is a famous variable—a sun that sometimes shines a thousand-fold more brilliantly than at others! It changes from the second magnitude to the ninth or tenth, its ANDROMEDA PEGASUS Map 16. period from maximum to maximum being about eleven months. During about five months of that time it is com- pletely invisible to the naked eye; then it begins to appear 79 ASTRONOMY WITH AN OPERA-GLASS. again, slowly increasing in brightness for some three months, until it shines as a star of the second magnitude, being then as bright as, if not brighter than, the most brilliant stars in the constellation. It retains this brilliance for about two weeks, and then begins to fade again, and, within three months, once more disappears. There are various irregulari- ties in its changes, which render its exact period somewhat uncertain, and it does not always attain the same degree of brightness at its maximum. For instance, in 1779, Mira was almost equal in brilliance to a first-magnitude star, but fre- quently at its greatest brightness it is hardly equal to an ordinary star of the second magnitude. By the aid of our little map you will readily be able to find it. You will per- ceive that it has a slightly reddish tint. Watch it from one of its maxima, and you will see it gradually fade from sight until, at last, only the blackness of the empty sky appears where, a few months before, a conspicuous star was visible. Keep watch of that spot, and in due course you will perceive Mira shining there again—a mere speck, but slowly brighten- ing—and in three months more the wonderful star will blaze again with renewed splendor. Knowing that our own sun is a variable star—though vari- able only to a slight degree, its variability being due to the spots that appear upon its surface in a period of about eleven years—we possess some light that may be cast upon the mys- tery of Mira’s variations. It seems not improbable that, in the case of Mira, the surface of the star at the maximum of spottedness is covered to an enormously greater extent than occurs during our own sun-spot maxima, so that the light of the star, instead of being merely dimmed to an almost im- perceptible extent, as with our sun, is almost blotted out. When the star blazes with unwonted splendor, as in 1779, we may fairly assume that the pent-up forces of this perishing sun have burst forth, as in a desperate struggle against ex- tinction. But nothing can prevail against the slow, remorse- THE STARS OF AUTUMN. 73 less, unswerving progress of that obscuration, which comes from the leaking away of the solar heat, and which consti- tutes what we may call the death of a sun. And that word seems peculiarly appropriate to describe the end of a body which, during its period of visible existence, not only pre- sents the highest type of physical activity, but is the parent and supporter of all forms of life upon the planets that sur- round it. . We might even go so far as to say that possibly Mira presents to us an example of what our sun will be in the course of time, as the dead and barren moon shows us, as in a magician’s glass, the approaching fate of the earth. Fortu- nately, human life is a mere span in comparison with the geons of cosmic existence, and so we need have no fear that either we or our descendants for thousands of generations shall have to play the tragic rd/e of Campbell’s ‘‘ Last Man,” and endeavor to keep up a stout heart amid the crash of time by meanly boasting to the perishing sun, whose rays have nurtured us, that, though his proud race is ended, we have confident anticipations of immortality. I trust that, when man makes his exit from this terrestrial stage, it will not be in the contemptible act of kicking a fallen benefactor. There are several other variable stars in Cetus, but none possessing much interest for us. The observer should look at the group of stars in the head, where he will find some in- teresting combinations, and also at Chi, which is the little star shown in the map near Zeta (€). This is a double that will serve as avery good test of eye and instrument, the smaller companion-star being of only seven and a half magnitude. Directly above Cetus is the long, straggling constellation of Pisces, the Fishes. The Northern Fish is represented by the group of stars near Andromeda and the Triangles.