ARIES

(the Ram.), constellation marking first sign of Zodaic (q.v.), symbolized by T. The point where the sun, pa ing through the intersection of the plane of the earth’s equator and the ecliptic (the plane of its revolution round the sun), cro es from south to north of the equator formerly marked its entry into A., and was called the First point of Aries, or the Spring Equinox. It was used as the zero line of celestial measurements. The other point of intersection of these two planes, through which the sun cro es from north of the equator to south, is the Autumnal Equinox.