It is many years, however, since any book has dealt with the telescope itself, apart from the often repeated accounts of the marvels it discloses. The present volume contains neither pictures of nebulæ nor speculations as to the habitibility of the planets; it merely attempts to bring the facts regarding the astronomer’s chief instrument of research somewhere within grasp and up to the present time.
The author cordially acknowledges his obligations to the important astronomical journals, particularly the Astro-physical Journal, and Popular Astronomy in this country; The Observatory, and the publications of the Royal Astronomical Society in England; the Bulletin de la Société Astronomique de France; and the Astronomische Nachrichten; which, with a few other journals and the official reports of observatories form the body of astronomical knowledge. He also acknowledges the kindness of the various publishers who have extended the courtesy of illustrations, especially Macmillan & Co. and the Clarendon Press, and above all renders thanks to the many friends who have cordially lent a helping hand—the Director and staff of the Harvard Observatory, Dr. George E. Hale, C. A. R. Lundin, manager of the Alvan Clark Corporation, J. B. McDowell, successor of the Brashear Company, J. E. Bennett, the American representative of Carl Zeiss, Jena, and not a few others.
Louis Bell.
Boston, Mass.,
February, 1922.
[CONTENTS]
| Page | ||
| [Preface] | vii | |
| Chap. | ||
| [I]. | The Evolution of the Telescope | 1 |
| [II]. | The Modern Telescope | 31 |
| [III]. | Optical Glass and Its Working | 57 |
| [IV]. | The Properties of Objectives and Mirrors | 76 |
| [V]. | Mountings | 98 |
| [VI]. | Eye-pieces | 134 |
| [VII]. | Hand Telescopes and Binoculars | 150 |
| [VIII]. | Accessories | 165 |
| [IX]. | The Testing and Care of Telescopes | 201 |
| [X]. | Setting up and Housing the Telescope | 228 |
| [XI]. | Seeing and Magnification | 253 |
| [Appendix] | 279 | |
| [Index] | 281 | |