Definition

ANGULAR DISTANCE east or west of the local CELESTIAL MERIDIAN; the arc of the CELESTIAL EQUATOR, or the angle at the CELESTIAL POLE, between the UPPER BRANCH of the local CELESTIAL MERIDIAN and the HOUR CIRCLE of a CELESTIAL BODY, measured eastward or westward from the local CELESTIAL MERIDIAN through 180°, and labelled E or W to indicate the direction of measurement. See HOUR ANGLE.