Handbook Of The Heavens

Text extracted from opening pages of book: HANDBOOK OF THE HEAVENS SPONSORED BY The ? American *% Cuseum of D atural History Editors HUBERT J. BERNHARD Director of Publication ftihior Astronomy Club DOROTHY A. Assistant Curator of thf llaydfn Planetarium', Adviser, Junior Astronomy Club HUGH S. RICE Associate in Astronomy, American. Museum, Sctrtl'fiJ'ic Associate, Junior Astrono WITH A * ORE WORD BY PROFESSOR HARLOW SHAPLEY l) irector t Harvard College Observatory New York WHITTLESEY HOUSE London MCGRAW-HILL BOOK COMPANY, INC. Dana K. Bailey, J. A. C. CIRCUMPOLAR TRAILS. A small camera, focused with a magnifier, was placed upon the ground and pointed at the North Star and its neighbors. In an hour's exposure, the stars revealed the rotation of the earth by recording on the photographic plate a fraction of the apparent daily circle of each. The group arrangement of the Little Dipper with the Pole Star at the end of the handle has been indicated at the initial position and the trails show its subsequent motion. This picture was made with a fine lens in the clear desert air of southern Arizona, and the original negative shows the trails of forty stars within the diurnal circle of Polaris. Anyone with even a box camera can make similar pictures. Copyright, 1935, by the McGRAW-HjLL BOOK COMPANY, INC. All rights reserved. This book, or parts thereof, may not be reproduced in any form without permission of the publishers SKCOM) PRINTING PUBLISHED BY WHITTLESEY HOUSE A division of the McGraw-Hill Book Company, Inc. Printed in the United States of America by The Maple Pres\ Co., York, Pa. To DR. CLYDE FISHER Curator of Astronomy American Museum of Naturaf History in charge of THE HAYDENPLANETARIUM CONTRIBUTORS DANA BAILEY ROBERT MILLER GIRARD BLOCK JAMES ROTHSCHILD RUTH FLEISCHER DICK SCHIRLING ROBERT FLEISCHER DOROTHY SCHOOF ANNESTA FRIEDMAN VERA WOLFSON Louis HEYNICK ACKNOWLEDGMENTS GRATEFUL acknowledgment is here made to the many people who have taken part in the preparation of this book. First thanks are due to the contributors, members of the Junior Astronomy Club at the American Museum of Natural History, whose genuine enthusiasm for their hobby of astronomy has made the book possible. We are indebted to Dr. Harlow Shapley for his unfailing interest and encouragement, and especially thank our many friends at the American Museum of Natural History. To Dr. Charles S. Adams, Director of Mount Wilson Ob servatory, and to Dr. Otto Struve, Director of Yerkes Observa tory, we are indebted for the photographic illustrations. The unique assistance rendered by Dean Guy Stanton Ford, Mrs. Chauncy Cooke, and Miss Anne E. Rumpf is gratefully acknowledged, as well as that of many others who have aided greatly in this undertaking. THE EDITORS. AMERICAN MUSEUM OF NATURAL HISTORY, September, i FOREWORD MY FIRST impulse in writing to the Junior Astronomers about their Handbook of the Heavens is to greet them in behalf of the profession and congratulate them on their unearthly interests. But the second is to warn them not to take the science too seriously. As an avocation, there is nothing more mind-cleans ing than astronomy; as a profession, it is a hard master. The young student should first discover in himself a high talent for mathematics or for making experiments, or the possession of a constructive imagination, before he ventures to change his interest in stars and planets, lenses and mirrors, from a healthy hobby into a business. The amateur astron omer and the unprofessional student are blessed with freedom from deadening responsibility; they answer only to the per sonal urge to do or to know. They can observe and read and think of velocities, masses, distances, and durations that are uncommon to the inhabitants of the earth's crust. They can play, at least in thought, with meteors and galaxies which are so different in size, so similar in origin, meaning, and obedience to cosmic laws. In a life of petty turmoils, the Junior Astronome