A Plain and Easy Guide to the Knowledge of the Constellations
SHOWING, IN TWELVE MAPS, THE POSITION FOR THE UNITED STATES OFTHE PRINCIPAL STAR GROUPS NIGHT AFTER NIGHT THROUGHOUT THE YEAR,WITH INTRODUCTION AND A SEPARATE EXPLANATION OF EACH MAP.
TRUE FOR EVERY YEAR
MAPS AND TEXT SPECIALLY PREPARED FOR AMERICAN STUDENTS
BY
AUTHOR OF "HALF HOURS WITH THE TELESCOPE," "EASY STAR LESSONS," "ALARGER STAR ATLAS," AND THE ARTICLE ON ASTRONOMY IN THE "AMERICANCYCLOPÆDIA" AND THE "CYCLOPÆDIA BRITTANICA." ETC.,ETC.
"Here I may sit and rightly spell
Of every star that Heav'n doth show."—MILTON.
The Heavens declare the glory of God; and the Firmament showethHis handiwork.—PSALMS xix: 1.
G. P. PUTNAM'S SONS
NEW YORK AND LONDON
The Knickerbocker press
1911
It is very easy to gain a knowledge of the stars, if the learnersets to work in the proper manner. But he commonly meets with adifficulty at the outset of his task. He provides himself with aset of the ordinary star-maps, and then finds himself at a losshow to make use of them. Such maps tell him nothing of the positionof the constellations on the sky. If he happen to recognizea constellation, then indeed his maps, if properly constructed,will tell him the names of the stars forming the constellation,and also he may be able to recognize a few of the neighboringconstellations. But when he has done this he may meet with a newdifficulty, even as respects this very constellation. For if helook for it again some months later, he will neither find it inits former place nor will it present the same aspect,—ifindeed it happen to be above the horizon at all.
It is clear, then, that what the learner wants is a set of mapsspecially constructed to show him in what part of the sky theconstellations are to be looked for. He ought on any night of theyear to be able to turn at once to the proper map, and in thatmap he ought to see at once what to look for, toward what pointof the compass each visible constellation lies, and how high itis above the horizon. And, if possible (as the present work showsis the case), one map ought to suffice to exhibit the aspectof the whole heavens, in order that the beginner may not be confusedby turning from map to map, and trying to find out how each fitsin with the others.
It is to fulfil these requirements that the present maps have beenconstructed. Each exhibits the aspect of the whole sky at a givenday and hour. The circumference of the map represents the naturalhorizon, the middle of the map representing the part of the skywhich lies immediately overhead. If the learner hold one of thesemaps over his head, so as to look vertically upwards at it, thedifferent parts of the horizon marked in round the circumferencebeing turned towards the proper compass points, he will see thesame view of the heavens as he would if he were to lie on his backand look upwards at the sky, only that the map is a planisphereand the sky a hemisphere.
But although this illustration serves to indicate the nature ofthe maps, the actual mode of using them is more convenient.
Let it first be noted that properly speaking the maps have neithertop