autumnal equinox


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autumnal equinox

n.
1. One of two points at which the ecliptic intersects the celestial equator. At the autumnal equinox, the sun is moving along the ecliptic in a southeasterly direction.
2. The moment at which the sun passes through this point on or about September 23, marking the beginning of autumn in the Northern Hemisphere and spring in the Southern Hemisphere.

autumnal equinox

n
1. (Physical Geography) the time at which the sun crosses the plane of the equator away from the relevant hemisphere, making day and night of equal length. It occurs about Sept 23 in the N hemisphere (March 21 in the S hemisphere)
2. (Astronomy) the time at which the sun crosses the plane of the equator away from the relevant hemisphere, making day and night of equal length. It occurs about Sept 23 in the N hemisphere (March 21 in the S hemisphere)
3. (Astronomy) astronomy
a. the point, lying in the constellation Virgo, at which the sun's ecliptic intersects the celestial equator
b. the time at which this occurs as the sun travels north to south (23 September)

autum′nal e′quinox


n.
1. See under equinox (def. 1).
2. Also called autum′nal point′. the position of the sun at the time of the autumnal equinox.
[1670–80]

au·tum·nal equinox

(ô-tŭm′nəl)
The moment of the year when the sun crosses the celestial equator while moving from north to south. It occurs on September 22 or 23, marking the beginning of autumn in the Northern Hemisphere. Compare vernal equinox.
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.autumnal equinox - September 22autumnal equinox - September 22        
Sep, Sept, September - the month following August and preceding October
equinox - either of two times of the year when the sun crosses the plane of the earth's equator and day and night are of equal length
autumn, fall - the season when the leaves fall from the trees; "in the fall of 1973"
2.autumnal equinox - (astronomy) the equinoctial point that lies in the constellation of Virgo
astronomy, uranology - the branch of physics that studies celestial bodies and the universe as a whole
equinoctial point, equinox - (astronomy) either of the two celestial points at which the celestial equator intersects the ecliptic
References in classic literature ?
It was by my account the 30th of September, when, in the manner as above said, I first set foot upon this horrid island; when the sun, being to us in its autumnal equinox, was almost over my head; for I reckoned myself, by observation, to be in the latitude of nine degrees twenty-two minutes north of the line.
While the country has been experiencing longer nights since the autumnal equinox last month, it will still take some time before markedly colder nights can be felt throughout the archipelago.
The autumnal equinox, which is also known as the September equinox, will see the start of fall in the Northern Hemisphere and spring in the Southern Hemisphere.
In the southern hemisphere, the autumnal equinox corresponds to the center of the Sun crossing the celestial equator moving northward and occurs on the date of the northern vernal equinox, meaning spring begins in Australia and South America.
The Autumnal Equinox marks a small gradual change in the weather as nights become cooler and daytime highs begin to drop as the calendar moves later into the year.
Mikelis Day is a harvest festival, the autumnal equinox when the sun turns towards winter and when day and night are of equal length --the start of the astronomical autumn.
During the eclipse the Harvest Moon - the full moon closest to the autumnal equinox - was darkened by the Earth's shadow.
On a lighter note, the occurrence is also known as the Harvest Moon because it falls closest to the autumnal equinox.
Day and night will be of equal length today due to the occurrence of a celestial phenomenon called autumnal equinox, which corresponds with the movement of the sun directly below the equator.
Precession also causes winter to lose time to Autumn, which will begin with the Autumnal Equinox on September 23.
The third is due on March 21, the Vernal Equinox, and the next after that on September 23, the Autumnal Equinox.
It's a Harvest Moon, which is the full moon closest to the autumnal equinox, and depending on the year, the Harvest Moon can come anywhere from two weeks before to two weeks after the autumnal equinox.