Related Links
Seasons of the Northern Hemisphere, 2016 Seasons for the Northern Hemisphere, 2017 Poetry for Fall The Seasons The Planets
At the autumnal equinox in Sept., the Sun appears to cross the celestial equator, from north to south; this marks the beginning of autumn in the Northern Hemisphere. The vernal equinox, also known as “the first point of Aries,” is the point at which the Sun appears to cross the celestial equator from south to north. This occurs in March, marking the beginning of spring in the Northern Hemisphere. On the date of either equinox, the Sun is above the equator and night and day are of approximately equal length; the word equinox is often used to refer to either of these dates. The equinoxes are not fixed points on the celestial sphere but move westward along the ecliptic, passing through all the constellations of the zodiac in 26,000 years. This motion is called the precession of the equinoxes. The vernal equinox is a reference point in the equatorial coordinate system.
