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1. (astronomy) the equatorial coordinate specifying the angle, measured eastward along the celestial equator, from the vernal equinox to the intersection of the hour circle that passes through an object in the sky; usually expressed in hours and minutes and seconds; used with declination to specify positions on the celestial sphere
   "one hour of celestial longitude equals fifteen degrees";
   - right ascension, RA

Derived forms: celestial longitudes

Type of: angular distance

Encyclopedia: Celestial longitude