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Astronomy Without a Telescope

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Astronomy Without a Telescope *i BY ^FL rETciT T J j <j, [p&z^ m : LIBRARY OF CONGRESS. I * UNITED STATES OF AMERICA.* ( ASTRONOMY WITHOUT A TELESCOPE: A GUIDE-BOOK TO THE VISIBLE HEAVENS, WITH ALL NECESSARY MAPS AND ILLUSTRATIONS. DESIGNED FOR THE USE OF SCHOOLS. E. COLBERT. CHICAGO : GEORGE & C. W. SHERWOOD. 1S69. Entered according to Act of Congress, in the year 1869, By GEO. & C. W. SHERWOOD, In the Clerk's Office of the District Court of the United States, for the Northern District of Illinois. CHURCH, GOODMAN AND DONNELLEY, PRINTERS, CHICAGO. BOND AND CHANDLER, ENGRAVERS. OfcrJDtfP PREFACE. There are four ways of regarding a subject — with the eye of sense, of reason, of fancy, and of faith. These severally constitute direct, inductive, dreamy, and substituted vision. The first is in itself interesting, yet not complete, or always reliable ; but it is especially valuable as being the basis of all that is true in the second, consistent in the third, and credible in the last. While in other departments of scientific tuition, the eye of sense is first appealed to, the would-be student of astronomy has generally been first taught to use some one of the other three ; dissertations on the profundities . of space and the acme of complicated motion, views of elaborately engraved monstrosities, with long chapters from the heathen mythology, and obscure descriptions of the invisible ; all these, instead of a simple delineation of the heavens, as visible to the naked eye. It is thus that astronomy, naturally pleasing, and normally useful, is a sealed book, except to the select few — a general ignorance due altogether to the lack of aid to the study. The following work is intended as an introduction to an acquaintance with the visible heavens ; to educate the eye into an ability to recognize the most prominent stellar groups. The maps are small and simple ; they present, in usable form, all the star groupings ordinarily visible to the naked eye in the United States, showing them, with little distortion, in the same relative positions as they occupy in the firmament, and without cumber- ing them up with painted figures — the form of the constellation is given only in faint outline. The greater portion of the maps are projected on the ecliptic as a base line, enabling the student to refer each star directly to the earth's path, and to trace out readily the course of a planetary body. The maps are so connected that a transition from one to another is easy, and the necessary explanatory text lies in, or near, the same opening of the book as the matter explained, while conciseness is aimed at throughout. The solar system is treated visually and deductively. No attempt has been made to describe positions or appearances inappreciable to the naked eye, except so far as they are necessary to a proper comprehension of that which can be seen by the unassisted vision. The phenomena of the heavenly motions are explained, and concise aids are furnished for determining, almost at a glance, the positions of the principal members of the solar family among the fixed stars, and with reference to the meridian and horizon, at any time during the last thirty years of the nineteenth century. The discussion of eclipses, and the elucidation of the means whereby we can calculate the absolute distances and bulks, and comparative weights of some of the heavenly bodies, are within the range of the simpler mathematics ; the only points involved, not included in the ordinary arithmetic, being the ratio of areas to squares, and contents to cubes, of like dimensions of similar figures, the composition of momenta, the analogies of plane and spherical right-angled triangles, and the addition of logarithms to find the product of their corresponding numbers. The elements of distance and bulk have been recalculated to the latest determinations of the solar parallax. The text is susceptible of verbal amplification, at the discretion of the teacher. The foot-notes are intended to serve, at once, as a table of contents, and as the groundwork of questions on the text. When they are used interrogatively, the pupil should be required to give a full explanation or definition of the subject referred to in each note. It is recommended that the student transfer the principal star groups to slate or paper, without outlines or letters. ...... ; CONTENTS. Earth's Motion on her own axis, and around ; the Sun ; Phenomena ; Circles of the Sphere ; Angular Meas- ures. 5-9 Stars. Distances and Names Sun's - Fixed ; Annual Journey along the Ecliptic ; Table. 10-12 Stars near the North Map No. I. Pole ; the Dipper ; Chair ; - - 13-16 ; Ursa Minor ; Cepheus Draco. II. Stars near the Vernal Map No. Equinox ; Square of Pegasus ; Perseus ; Andromeda ; Lacerta ; Pisces Aries ; Musca ; Trianguli. - - ........ 17-19 III. Zodiac ; Cetus ; Phoenix Map No. The ; Eridanus. ........ 20-21 Map No. rV. Three to six hours in Right Ascension; Perseus; Taurus; The Pleiades; Auriga; Orion; Hydrus; Reticulum Rhomboidalis ; Doradus. --------- 22-24 Map No. V. Gemini ; Telescopium Herschelium ; Cancer ; Canis Minor ; Canis Major ; Lepus ; Columba ; 25-27 Noachi Lynx ; Camelopardalus. .....-..-. Ursa Major ; Canes Venatici ; Minor. 28-29 Map No. VI. Leo ; Leo ....... Virgo ; Berenices ; Crater Corvus ; 30-31 Map No. VII. Coma ; Hydra. ------ Map No. VIII. Libra ; Scorpio ; Ara ; Triangulum Australis ; Ophiucus et Serpens ; Norma Euclidis ; Circinus. 32-34 Map No. IX. Taurus Poniatowski ; Aquila et Antinous ; Delphinus ; Sagittarius ; Corona Australis ; Micro- scopium ; Grus ; Indus et Pavo ; Telescopium. ........ 35-36 ; Piscis 37-38 Map No. X. Capricornus Aquarius; Australis; Pegasus ; Equuleus. ..... Borealis ; Hercules ; Lyra. 39-40 Map No. XI. Bootes ; Corona ....... Map No. XII. Argo ; Robur Caroli ; Stars near the South Pole ; the Milky Way. - - - 41-42 Map No. Xni. Cygnus ; Centaurus et Crux ; Lupus. -------- 43-44 Table of Fixed Stars. Magnitudes ; Names ; Right Ascensions, North Polar Distances, Longitudes, and Latitudes on January 1st, 1875 ; Annual Variations. -...-- 45-53 Culminating, Rising and Setting. Ascensional Ditlerences; Refraction; To Find Right Ascension and Decli- nation from Longitude and Latitude. --------- 54-59 Map No. XIV. Principal Stars Visible in North Latitude 40° ; Positions with reference to the Meridian and Horizon. - 60-61 The Solar System. Jupiter, Venus, Mercury, Mars, Saturn, Uranus, Neptune ; Phenomena of Motion Heliocentric and Geocentric Positions ; Tables of Places from 1870 to 1900. ... - 62-70 ; Parallax ; Eclipses ; The Moon. Lunation Measures of Time ; Chronology. ----- 71-78 Distance and Bulk. Measuring the Earth and Moon ; Sun's Parallax ; Earth's Orbit ; The Sun ; Laws of and its - Motion ; Mutual Attraction Results ; Precession ; The Tides. 79-88 Elements of the Solar System. Distances, Magnitudes, Bulks, etc., of the Planets and Luminaries. - 89-90 Other Members of thf Family. Planetoids; Rings; Satellites, Comets; Aerolites. - - - 91-95 Origin. 96-98 The Fixed Stars. Parallax; Distances; Numbers; Magnitudes ; Light; Individual Motion ; Common Absolute Motion of the Solar System. Sun's Orbit ; Real Paths of the Earth and Moon. - - 99-100 Index. - - - - 101-104 INTRODUCTORY. 1. The study of Astronomy includes two classes is a large globe, nearly eight thousand miles in of objects — the stationary, and the wandering. diameter (the greatest distance through it is 2. The first class consists of the Fixed Stars ; so 41,847,200 feet). We live on its exterior, the called, not because they are absolutely immovable, upright position at any place being perpendicular but for the reason that they change their relative to the surface at that spot ; the centre of the globe positions very slowly, a thousand years making but is, every where, the point to which all bodies tend little difference in their apparent locations with to fall, in obedience to the law of attraction of regard to each other. gravitation. The earth turns round once in twenty- 3. The second class comprises the Sun, Moon, four hours, in just the same way that a school Planetary Bodies, Asteroids, Comets, etc. ; they globe is rotated on its axis ; except that the earth change their apparent places among the fixed moves in space, with no frame work to support it. stars with varying degrees of rapidity. Their (?. Take a round ball, of yarn (or an orange), and paths in the heavens can only be traced out by run a piece of wire through its centre, making it one who has an ocular acquaintance with the lead- pass entirely through the ball. Hold one end of ing members of the first named class. the wire firmly in the hand, pointing the other end 4. The fixed stars appear to be set in the surface in the direction of the North, but sloping upwards, of a hollow sphere. If we watch them attentively about midway between the level and upright posi- for an hour or two, ou a bright night, we notice a tions ; turn the ball slowly round on the wire. If connected movement. Those in the Eastern part a small insect were gummed fast to the surface of of the heavens are slowly rising, those in the South the ball, at a little distance from the northern end are passing towards the West, and those in the of the wire, he would preserve his position with "West are sinking towards the horizon. If, stand- regard to the centre of the ball, but, at each rota- ing any where in the Northern States, we face the tion, every visible object would appear to move North, and look up about half-way between the round in a circle, the centre of which would be in point overhead and the horizon, we may select any the wire. star, and, following its movements, see that it trav- 7. Enlarge the ball to a globe of nearly eight els around but a small circle ; and there is one dull thousand miles in diameter, replace the insect by red star, shining out timidly in the midst of com- a human being, held to the surface by the attrac- parative blankness, whose circle of apparent travel tion of gravitation, let the globe rotate in space, is so small, that the aid of an instrument is neces- instead of being sustained on a wire, and let the sary to enable us to detect a movement.
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