Mars—a challenge to astronomers: This photo of the red planet, always a favorite of observers, is one of the finest. (W. S. Finsen, Union Obs., Johannesburg)
All of us, from childhood, have gazed at the sky in wonder. Sun and Moon, the wandering planets, the fiery trails of comets and meteors—these are things to marvel at. Man will never tire of looking up into the tremendous, sparkling bowl of space.
Sky watching was undoubtedly a pastime of prehistoric man. The ancient Egyptians and Babylonians, several thousand years ago, observed the heavens carefully enough to devise quite accurate calendars. Observations by Copernicus, Galileo, and others in the sixteenth and seventeenth centuries were among the first great steps to modern science. Even today, the science of astronomy depends on observation.
ASTRONOMY FOR EVERYBODY Astronomy is for the amateur as well as the professional. The amateur can see for himself the sights that stirred Galileo, the Herschels, and other great astronomers. A high-school boy may be the first to see a comet, a rug salesman may discover a nova, and a housewife can observe and map meteor showers. An amateur’s faithful observations of a variable star may be just the data an observatory needs.
Although in some regions weather and climate are often unfavorable, any interested person in any part of the world can become a sky observer. The aspect of the sky differs from place to place, but the majesty of Sun and Moon, of stars and planets and nebulas, is to be seen everywhere.
Mars—a challenge to astronomers: This photo of the red planet, always a favorite of observers, is one of the finest. (W. S. Finsen, Union Obs., Johannesburg)
This book is a guide to observing—to the use of binoculars and telescopes, the locating of sky objects, and what objects to look for and how best to see them. The beginning observer should have also a book on general astronomy. Even a little knowledge greatly increases the pleasure of observing, and it prepares us to undertake real astronomical projects. Most old hands have found that the fun of amateur astronomy is greatest when they are working on observation programs that are scientifically useful.
Great Nebula in Orion: This famous object was painted as seen by the artist in his 8-inch telescope at 200 power. The pattern of four stars near the center is the well-known, colorful Trapezium.
OBSERVING WITH UNAIDED EYES Even an observer without binoculars or a telescope can see many wonders of the heavens. The important thing is to know how to look and what to look for. The constellations can be traced and identified. Some star clusters can be located, and eclipses and some comets observed. The changing positions of Sun, Moon, and the brighter planets can be closely watched, and some artificial satellites can be seen. The brightness and length of meteor trails can be estimated. Get used to finding your way about the sky with the eyes alone before trying a telescope.
BINOCULARS AND TELESCOPE Your first look at the heavens through good binoculars can be exciting. Binoculars with 50mm. lenses gather about 40 times as much light as the eye alone, revealing such features as mountains and craters of the Moon, sunspots, the four larger satellites of Jupiter, double stars and star clusters, and luminous clouds of cosmic gas such as the famous nebula in Orion. (Before observing the sun, see here)
With no more than binoculars, some observers do useful scientific work, such as recording light changes in variable stars and watching for novas and comets. A telescope is obtained by every serious amateur sooner or later. Refractors, with lenses 1½ to 4 inches diameter, and reflectors, with mirrors of 3 to 6 inches, are popular types. The light-gathering and magnifying power of telescopes brings out details of the Moon’s surface. It reveals Jupiter’s larger satellites and its banded clouds, as well as markings on Mars and the rings of Saturn. With telescopes we can “split” double stars and distinguish star clusters, nebulas, comets, and sunspots. We can watch the Moon occult (that is, pass in front of) stars and planets. Light fluctuations of faint variable stars and novas can be detected.
Good small telescopes can give surprising performance. When conditions are right, an observer with a good 3-inch refractor or 6-inch reflector can see some features of Jupiter and Saturn more distinctly than they appear in observatory photographs.
Telescope on wheels: This homemade 8-inch reflector is kept in the garage and wheeled out at observing time. (William Miller)
FUN WITH THE CAMERA Many amateurs make use of the camera. The eye is sensitive only to the light it is receiving in the present instant, but photographic film is sensitive to light received over a long period of exposure. An amateur’s camera can detect faint objects which the eye, even with the aid of a telescope, could never see. Even a simple camera gives exciting and useful results.
MAKING A TELESCOPE Some serious amateurs, not content with factory-made telescopes, make their own. They grind the lenses and mirrors, and design the mountings. It takes special knowledge and skill, yet hundreds of amateurs have made instruments that perform splendidly. Telescope-making classes are held at some planetariums, universities, and observatories. Books on telescope making are available from booksellers.
Transit of Mercury, Nov. 14, 1907: The movement of a planet across the Sun’s disk is a rare sight. Arrows point to Mercury and show the direction of its path. (Yerkes Obs.)
ORGANIZATIONS OF AMATEURS Many amateur observers belong to national organizations. These give members information on equipment, observing techniques, and standard methods of reporting their work. They set up observing programs and receive observational data from members. Data are sent to observatories for use in programs of research. Some organizations publish news of developments that interest amateurs. Local groups observe together, compare equipment, and promote public interest in astronomy.
For a serious amateur: This homemade 12-inch reflector, equipped with a camera, can give high performance. (Clarence P. Custer, M.D.)