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

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

From "Cosmos" by Carl Sagan

The Mesopotamian of to-day is surely not the superior of his sculptured ancestors who observed and measured the precession of the equinoxes nearly 6,000 years ago.

From The Color Line A Brief in Behalf of the Unborn by Smith, William Benjamin

Owing to the precession of the equinoxes, however, the vernal equinoctial point, which was formerly in this constellation, has now advanced into the constellation Pisces, as we saw above.

From Astronomy with an Opera-glass A Popular Introduction to the Study of the Starry Heavens with the Simplest of Optical Instruments by Serviss, Garrett Putman

This is called the precession of the equinoxes.

From The New Gresham Encyclopedia Volume 4, Part 2: Ebert to Estremadura by Various

The earth's equatorial protuberance, being acted on by the attraction of the sun and moon, must disturb its axis of rotation in a calculated manner; and thus is produced the precession of the equinoxes.

From Pioneers of Science by Lodge, Oliver, Sir