n.(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
同义词：right ascensionRA
英汉双解大词典
celestial longitude
1.
N（名词）
the angular distance measured eastwards from the vernal equinox to the intersection of the ecliptic with the great circle passing through a celestial body and the poles of the ecliptic 黄经 (Also called ecliptic longitude)