Precession of the equinoxes: Quick Facts

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Diagram showing Earth's axis of rotation tilted at about 23.5 degrees, illustrating precession as the axis traces a circular path over 26,000 years, shifting alignment from Polaris, the current North Star, to Vega. Labels indicate the plane of Earth's orbit and the changing orientation of the axis over time.

A diagram of the celestial sphere with Earth at the center, showing the celestial equator, ecliptic, and labeled positions of the vernal and autumnal equinoxes, as well as the north celestial and ecliptic poles.

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Topics

precession Equinox Vernal equinox Autumnal equinox What’s the Difference Between a Solstice and an Equinox?

Key People

Nicolaus Copernicus

Nicolaus Copernicus

Polish astronomer

Jean Le Rond d'Alembert.

Jean Le Rond d’Alembert

French mathematician and philosopher

Engraving of six astronomers, with Hipparchus seated at center and, from left to right, Galileo, Johannes Hevelius, Tycho Brahe, Nicolaus Copernicus, and Ptolemy standing, each holding scientific instruments.

Hipparchus

Greek astronomer

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Kidinnu

Babylonian astronomer and mathematician

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al-Battānī

Arab astronomer and mathematician

The orbits of the planets and other elements of the solar system, including asteroids, Kuiper belt, Oort cloud, comet

Space Odyssey

Nicolaus Copernicus. Nicolas Copernicus (1473-1543) Polish astronomer. In 1543 he published, forward proof of a Heliocentric (sun centered) universe. Coloured stipple engraving published London 1802. De revolutionibus orbium coelestium libri vi.

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