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physical phenomena > event > celestial event > periodic celestial event > equinox > vernal equinox
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vernal equinox
(First Point of Aries, spring equinox)
subjectfact 
vernal equinoxhas date on or around 21 Marchhas source: Abbot, D. 1984 Astronomers, Peter Bedrick Books, New York, 2001-09-27 09:30:03.0
has synonym First Point of Arieshas source: Hopkins, J. 1976 Glossary of Astronomy and Astrophysics, University of Chicago Press, 2001-09-27 09:30:03.0
has synonym spring equinoxhas source: Abbot, D. 1984 Astronomers, Peter Bedrick Books, New York, 2001-09-27 09:30:03.0
has definition The ascending node of the ecliptic on the celestial equator; also the time at which the apparent longitude (see apparent place; longitude, celestial) of the Sun is 0°.has source: Seidelman, P. 1992 Explanatory Supplement to the Astronomical Almanac, University Science Books, Mill Valley, CA, 2001-09-27 09:30:03.0
has definition The point of intersection between the ecliptic and the celestial equator, where the Sun crosses from south to north. It is sometimes called the First Point of Aries because several thousand years ago it was in Aries. Because of precession it has now slid west into Pisces and in 200-300 years it will edge into Aquarius. By definition, the vernal equinox is at α = 0°, δ = 0°.has source: Hopkins, J. 1976 Glossary of Astronomy and Astrophysics, University of Chicago Press, 2001-09-27 09:30:03.0
is an instance of equinox2001-09-27 09:30:03.0
equinoxhas period 1 year2001-09-27 09:30:03.0
eventhas duration2001-09-27 09:29:57.0
has time of occurrence2001-09-27 09:29:57.0