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

These are not upon the surface, but they are as real and as capable of being accurately noted as the amount of the rain-fall, or the precession of the equinoxes.

From Village Life in China A Study in Sociology by Smith, Arthur H.

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

Mahometan and Chinese know what we know of leap-year, of the Gregorian calendar, and of the precession of the equinoxes.

From The Voice of Science in Nineteenth-Century Literature Representative Prose and Verse by Various

The combined effect of the precession of the equinoxes and of the excentricity of the earth's orbit.

From Island Life Or the Phenomena and Causes of Insular Faunas and Floras by Wallace, Alfred Russel