The component of precession caused by the Sun and Moon is called lunisolar precession; that caused by the action of the planets is called planetary precession. The sum of lunisolar and planetary precession, known as general precession, results in a westward movement of the equinoxes (the nodes of the ecliptic) known as the precession of the equinoxes. This movement amounts to an average of about 50.3" per year – the so-called precession constant. Precession means that a number of different stars in the circumpolar regions of the celestial sphere serve as pole stars on a cyclical basis.
Related categories CELESTIAL MECHANICS
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