Autumnal equinox
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Image:Earth-lighting-equinox EN.png
The autumnal equinox (or fall equinox) marks the beginning of astronomical autumn. It occurs during the month of September in the Northern Hemisphere, and during March in the Southern Hemisphere. In Chinese culture it marks the middle of autumn. At the same moment that the autumnal equinox occurs in one hemisphere, it is the time of the vernal equinox in the other hemisphere.
In 2006, the autumnal equinox of the Northern Hemisphere falls on September 23 at 04:03 UTC<ref>Template:Cite web</ref><ref>Template:Cite web</ref>. In the Southern Hemisphere the equinox occurs at 18:26 UTC on 20 March.
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Astronomy
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The Celestial Equator and the Ecliptic are two Great Circles. As such, they intersect at two points, the Equinoxes. When the Sun, which moves along the Ecliptic, occupies the point that crosses the Equator while heading south, it is the time of the Autumnal Equinox.
Due to the Precession of the Equinoxes, the point of intersection moves completely around the sky in a 25,800-year cycle. This century it is in the western end of Virgo near the star Zavijava (β Vir) and moving slowly toward Leo.
Holidays
Autumnal Equinox Day (秋分の日, Shūbun no hi) is an official national holiday in Japan, and is spent visiting family graves, and holding family reunions.
In the UK Harvest festival falls around this time.
The autumnal equinox is when the Wiccan Sabbat of Mabon is celebrated.
Autumnal Equinox Day is also "New Year's Day" in the French Republican Calendar, which was in use from 1793 to 1805. The French First Republic was proclaimed and the French monarchy was abolished on September 21, 1792, making the following day, Autumnal Equinox Day that year, the first day of the "Republican Era" in France.
The solar term Qiufen in Chinese astronomy
Qiufen (秋分) is a solar term which begins when Sun lies between the celestial longitude of 180° and 195°. It sometimes refers in particular to the day when Sun exactly at the celestial longitude of 180°. It usually begins around September 23, and ends around October 8.