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An instrument designed to measure or estimate the degree of blueness of light, as of the sky.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.



a colorimeter designed for measuring the color of the clear daytime sky. A cyanometer has a one-dimensional scale that makes it possible to measure colors in the sequence from white through whitish blue to saturated blue. A distinction is made between relative and absolute cyanometers. With relative cyanometers, the color of the sky is compared with a set of standards; for example, the cyanometer devised by Saussure uses slips of paper tinted various shades of blue as the standards. Absolute cyanometers make it possible to express observational results as a color temperature or some other color characteristic used in colorimetry. The first cyanometer was fabricated by H. B. Saussure in the late 18th century. In 1919, G. A. Tikhov invented a cyanometer in which the color of the sky is compared with the color of a sapphire plate.

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