blink comparator

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blink comparator

See comparator.
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 It might be outdated or ideologically biased.

Blink Comparator


an astronomical instrument for finding variable stars, minor planets, and stars with large proper motions on photographic plates of the starry sky. The blink comparator is utilized in comparing two photographic plates of the same portion of the sky taken on the same instrument at different times. Both of the photographic plates are viewed through one eyepiece, and by flipping a special flap slide—that is, “blinking”—either one can be seen alternately. The platform on which the photographic plates are mounted is adjustable, which makes it possible to orient the plates with respect to each other in such a way that stars whose mutual position has not changed appear fixed upon rapid blinking. At the same time, objects that have shifted in the time interval between two exposures appear to jump. The images of variable stars have different diameters on the photographic plates, and a flickering or pulsating effect appears upon blinking.


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

blink comparator

[′bliŋk kəm′par·əd·ər]
An optical instrument used to alternately view two pictures in the same visual field in rapid succession, to detect small differences in similar images.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
References in periodicals archive ?
Zeiss Blink Comparator: Among the larger instruments is a Zeiss blink stereo-comparator (left), dating from the first decade of the 20th century.
Traditionally, two plates of the samefield of the sky--from different years-- are put into a machine called a blink comparator, which shifts a human observer's vision rapidly between them.
Sprott also offers a free Blink Comparator utility that can align and crop several photographs and let you cycle through them to look for changes in the field, such as stars varying in brightness or asteroids moving.
The success of Liller's program--aside from his desire to photograph the Milky Way whenever possible--can be attributed to his use of a blink comparator, a device that allows him to display in quick succession two alternating images of the same field taken at different times.
This prompted him to build an ingenious blink comparator using two slide projectors, and he eventually founded a sky-patrol program called Problicom.
Nowadays new variable stars are commonly detected by comparing photographs of a star field taken on different dates using some kind of blink comparator. Williams used a more laborious method, which he described as follows:
Sure enough, the Scottish-born astronomer was one of my early customers in a business venture that sprang up from the homemade blink comparator I had described in this department (S&T: March 1984, page 275).
A blink comparator is a device for viewing the same sky area on two photographs taken at different times.