Source : WordNet®

celestial longitude
     n : (astronomy) the angular distance eastward along the
         celestial equator from the vernal equinox to the
         intersection of the hour circle that passes through the
         body; expressed in hours and minutes and second; used
         with declination to specify positions on the celestial
         sphere; "one hour of right ascension equals fifteen
         degrees" [syn: {right ascension}, {RA}]