north polar distance
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Related to north polar distance: North Polar Region
north polar distance(NPD) The angular distance of a celestial object from the north celestial pole, measured along the object's hour circle. It is the complement of the object's declination (90°–δ) and is sometimes used instead of this coordinate in the equatorial coordinate system.
Collins Dictionary of Astronomy © Market House Books Ltd, 2006
north polar distance[′nȯrth ¦pō·lər ′dis·təns]
The angular distance between a celestial object and the north celestial pole.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.