plate constants

plate constants

[′plāt ‚kän·stəns]
(astronomy)
Coefficients that appear in linear equations used to derive the standard coordinates of the position of a star on a photographic plate from the measured coordinates of the star's image on the plate.
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References in periodicals archive ?
Slowly, over a span of six decades, about 150 volumes of data were published containing positional measurements of stars with respect to plate centers, as well as the plate constants and formulas required to convert the x, y measures to right ascension and declination.
Even when this was undertaken, the plate constants originally published did not yield the accuracy inherent in the plate measures themselves.
Kox of Hamburg Observatory and Paul Lacroute and Armand Valbousquet of Strasbourg Observatory redetermined plate constants for the entire Northern Hemisphere.