precession of the equinoxes

American  

noun

1. the earlier occurrence of the equinoxes in each successive sidereal year because of the slow retrograde motion of the equinoctial points along the ecliptic, caused by the precession of the earth's axis of rotation; a complete precession of the equinoxes requires about 25,800 years.

2. the resulting drift of celestial coordinates with respect to the positions of celestial objects.

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precession of the equinoxes British  

noun

1. the slightly earlier occurrence of the equinoxes each year due to the slow continuous westward shift of the equinoctial points along the ecliptic by 50 seconds of arc per year. It is caused by the precession of the earth's axis around the ecliptic pole, with a period of 25 800 years

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Etymology

Origin of precession of the equinoxes

First recorded in 1615–25

Example Sentences

See Examples For:

precession of the equinoxes

But modern astrologers have forgotten about the precession of the equinoxes, which Ptolemy understood.

From "Cosmos" by Carl Sagan

Even the tides and precession of the equinoxes and Bradley's nutation were accounted for and explained.

From Astronomy: The Science of the Heavenly Bodies by Todd, David Peck

The al-Aalam mentioned above was also an able astronomer, and in addition to numerous observations made at Baghdad, he determined with great care the precession of the equinoxes.

From Astronomical Curiosities Facts and Fallacies by Gore, J. Ellard

Hipparchus and other thinkers had discovered the fact of the precession of the equinoxes, though there was no adequate theory to account for it until Copernicus formulated his "motion of declination."

From The gradual acceptance of the Copernican theory of the universe by Stimson, Dorothy

This enabled him to ascertain the motion of the equinoxial points, and his value of the constant of precession of the equinoxes is exceedingly accurate for a first determination.

From Astronomy: The Science of the Heavenly Bodies by Todd, David Peck