(astronomy) the angular distance of a celestial body north or to the south of the celestial equator; expressed in degrees; used with right ascension to specify positions on the celestial sphere
Either of two corresponding parallels of celestial latitude that are the limits of the apparent northern and southern passages of the sun. (天球的)回归线代表太阳经过的最北视界线与最南视界线的两条相应的天球纬线