Literally, the time of equal day and night. This is the time when the Sun crosses the celestial equator. There are two equinoxes; Vernal (Spring), around March 21st and Autumnal (Autumn) around September 23rd. On these dates, day and night are equal. Actual dates and times vary due to the Earth\'s precession. This term is frequently, although incorrectly, used to describe a point lying on the Ecliptic.