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(ass-troh-fŏ-tog -ră-fee) Astronomical photography.
Collins Dictionary of Astronomy © Market House Books Ltd, 2006
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.



a method of astronomical observation based on photographing celestial bodies with astro-graphs. Astrophotography was introduced as an astronomical technique in the middle of the 19th century. It replaced visual observations because of its advantages, including the ability of photographic emulsion to store light energy, which makes possible the observation of faint celestial bodies; the ability to obtain simultaneously in one photograph the images of many objects (for example, stars in the Milky Way) or of one object in all its details (for example, the corona of the sun); and objectivity and ease of data storage.

In a narrow sense, astrophotography refers to photographic astrometry, that is, the branch of astrometry in which photography is used to solve such problems as the determination of the positions of stars in the celestial sphere, the measurements of their movements and of the distances to them, the relative displacements of stars in binary and multiple systems or of satellites orbiting planets, and so forth. Most astrometrical problems are solved by measuring the angles between star positions at given time periods. Using the methods of astrophotography gives the measurement on a photograph of a specific region of the sky, the rectangular coordinates of the object to be studied, and a certain number of reference stars with the equatorial coordinates α and δ, which are known from catalogs. Measurements are made with the aid of special coordinate-measuring machines. Measurements by this method do not normally exceed a one-μm margin of error. The results of such measurements permit the determination of the α and δ coordinates for the bodies under study, which might be a large or small planet, a comet, a meteor, the moon, a star, and so forth.

Proper motions of stars are determined from photographs made at ten-year intervals. Distance calculations are based on measurements of angles between positions to a celestial body at different times of the year, that is, from different points of the earth’s orbit. In this way the distances to stars are determined with an accuracy to several thousandths of a second of arc, which corresponds to distances of 200–300 parsecs. Astrophotography makes possible the measurement of the relative position of binary star components if the distance between them is not less than 1”—otherwise, the star images on the photograph touch or overlap each other. Of exceptional interest are the invisible companions of stars, which cause noticeable periodic displacements of the stars themselves. The masses of such invisible companions have been found to be comparable to the masses of the planets in the solar system. Special instruments were designed in the 1950’s for photographing and determining the positions of artificial satellites of the earth moving rapidly through outer space, and special methods were also developed for determining their α and δ coordinates and the time periods of the observations.


Deich, A. N. “Osnovy fotograficheskoi astrometrii.” In Kurs astrofiziki i zvezdnoi astronomii, 3rd ed., vol. I. Moscow-Leningrad, 1951.
Martynov, D. Ia. Kurs prakticheskoi astrofiziki, 2nd ed. Moscow, 1967.


The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.


McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
References in periodicals archive ?
The Welsh-born Isaac Roberts had made a fortune in the construction business, and he applied his wealth toward an ambitious program in celestial photography. His observatory at Crowborough, Sussex, was among the finest in Britain, housing a 20-inch f/5 Grubb reflector and a 7-inch Cooke refractor sharing a twin mount.
Barnard began experimenting in wide-field celestial photography in 1889, six years before Isaac Roberts's unflattering display of his work.
Upon his return to the United States, Draper decided to erect on the grounds of his family estate at Hastings-on-Hudson the first observatory in America expressly for celestial photography. (The estate is now a museum and archive.) He sought advice from renowned British astronomer John Herschel, who suggested that he abandon the troublesome speculum-mirror telescope design that had endured since the time of Isaac Newton and instead perfect the art of grinding and silvering glass disks.
Henry's detailed report, "On the Construction of a Silvered Glass Telescope, Fifteen and a Half Inches in Aperture, and Its Use in Celestial Photography," became the standard how-to manual for generations of amateur telescope makers.
With a convert's passion, he advocated to his fellow professional astronomers on behalf of celestial photography. This was a risky venture at the time; in 1887 Gill's research funding was suspended by England's Royal Society.
The rest of my teenage years were spent with a succession of simple homemade telescopes - a 4-inch, then a 6, and finally an 8 - observing variable stars, trying my hand at celestial photography, and logging Messier objects and other sights.
Impressive celestial photography is a lot more feasible for amateurs now than it was a generation ago.