Produced by Jason Isbell and the Online Distributed Proofreading Team at https://www.pgdp.net [Illustration: PLATE I. Maps I.-IV.] HALF-HOURS WITH THE TELESCOPE; BEING A POPULAR GUIDE TO THE USE OF THE TELESCOPE AS A MEANS OF AMUSEMENT AND INSTRUCTION. BY RICHARD A. PROCTOR, B.A., F.R.A.S., AUTHOR OF "SATURN AND ITS SYSTEM," ETC. WITH ILLUSTRATIONS ON STONE AND WOOD. * * * * * An undevout astronomer is mad: True, all things speak a God; but, in the small Men trace out Him: in great He seizes man. YOUNG. * * * * * NEW YORK: G.P. PUTNAM'S SONS. 1873. LONDON: PRINTED BY WILLIAM CLOWES AND SONS, STAMFORD STREET AND CHARING CROSS. PREFACE. The object which the Author and Publisher of this little work have proposed to themselves, has been the production, at a moderate price, of a useful and reliable guide to the amateur telescopist. Among the celestial phenomena described or figured in this treatise, by far the larger number may be profitably examined with small telescopes, and there are none which are beyond the range of a good 3-inch achromatic. The work also treats of the construction of telescopes, the nature and use of star-maps, and other subjects connected with the requirements of amateur observers. R.A.P. _January_, 1868. CONTENTS. CHAPTER I. PAGE A HALF-HOUR ON THE STRUCTURE OF THE TELESCOPE 1 CHAPTER II. A HALF-HOUR WITH ORION, LEPUS, TAURUS, ETC. 33 CHAPTER III. A HALF-HOUR WITH LYRA, HERCULES, CORVUS, CRATER, ETC. 47 CHAPTER IV. A HALF-HOUR WITH BOOTES, SCORPIO, OPHIUCHUS, ETC. 56 CHAPTER V. A HALF-HOUR WITH ANDROMEDA, CYGNUS, ETC. 66 CHAPTER VI. HALF-HOURS WITH THE PLANETS 74 CHAPTER VII. HALF-HOURS WITH THE SUN AND MOON 93 DESCRIPTION OF PLATES. PLATE I.--_Frontispiece._