March equinox


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Related to March equinox: September equinox, June solstice

March equinox

[′märch ′ē·kwə‚näks]
(astronomy)

vernal equinox

vernal equinoxclick for a larger image
i. That point of intersection of the ecliptic and the celestial equator occupied by the sun as it changes from a south to a north declination, on or about March 21. Also called the March equinox or the first point of Aries.
ii. That instant the sun reaches the point of zero declination when crossing the celestial equator from south to north.

equinox

equinoxclick for a larger image
Positions of sun and the earth at spring and autumnal equinoxes.
i. One of the two points of intersection of the ecliptic and the celestial equators, occupied by the sun when its declination is 0°. Also called an equinoctial point. That point occupied on or about March 21, when the sun's declination changes from south to north, is called the vernal equinox, spring equinox, March equinox, or first point of Aries that point occupied on or about September 23, when the declination changes from north to south, is called the autumnal equinox, September equinox, or first point of Libra. Equinox is often used to mean vernal equinox, when referring to the origin of measurement of right ascension and celestial longitude. At the time of equinox, the duration of day and night is the same or equal.
ii. That instant the sun occupies one of the equinoctial points.
References in periodicals archive ?
However, in 2000, 2008, and 2016, the observational Nisan 15 was more than 30 days after March 21, which means that, in those years, the 15th day of the previous lunar month fulfilled the March equinox requirement of TB Sanhedrin 11b while not fulfilling the aviv requirement.
The 2009 March equinox on Saturn is now behind us, and during the next years we will see the rings opening until the planet reaches its June solstice in 2017.
Seasons on Saturn Season Date March equinox 3 March 1980 June solstice 11 December 1987 September equinox 19 November 1995 December solstice 26 October 2002 March equinox 10 August 2009 June solstice 22 May 2017 Table 2.
If 0[degrees] is taken as the March equinox, this corresponds to angles of 0[degrees], 90[degrees], 180[degrees] and 270[degrees].
The ecclesiastical dates of the March equinox (deemed to be March 21st) and full Moon do not always agree with those defined astronomically.
I refer to the full Moon nearest the September equinox (or nearest the March equinox for those living south of the equator), the one commonly called the Harvest Moon.
This comes just nine nights after the March equinox, when (for observers north of the tropics) the ecliptic makes the steepest possible angle with the horizon at sunset.
That same night the Sun reaches the March equinox point in western Pisces, heralding the start of spring in the Northern Hemisphere and autumn in the Southern.
So it is the antisolar point, the point directly opposite the Sun in our sky, at the time of the March equinox (on March 20th this year).