Of a celestial object as seen from a particular location, the difference between the local sidereal time and the right ascension (H.A. = L.S.T. - R.A.).
the angle of a star's location away from the point on the celestial equator due south of an observer in the northern hemisphere. Postive is to the east of that point, negative to the west. It is measured in hours where 1 hour = 15°.
angular distance on the celestial sphere measured westward along the celestial equator from the meridian to the hour circle that passes through a celestial object.