Both solar time and sidereal time make use of the regularity of Earth's rotation about its polar axis: solar time is reckoned according to the position of the Sun in the sky while sidereal time is based …

The meaning of SIDEREAL is of, relating to, or expressed in relation to stars or constellations : astral.

Jun 10, 2012 · Sidereal time measures the rotation of our planet relative to the stars. It allows astronomers to keep time without worrying about the motion of Earth around the sun.

SIDEREAL definition: determined by or from the stars. See examples of sidereal used in a sentence.

Sidereal time, time as measured by the apparent motion about the Earth of the distant, so-called fixed, stars, as distinguished from solar time, which corresponds to the apparent motion of the Sun.

Aug 15, 2025 · Sidereal time, unlike solar time (everyday clock time), is referenced to the stars and is defined as the right ascension of the celestial object on the local meridian. Sidereal time varies with...

By convention, rotation periods of planets are given in sidereal terms unless otherwise specified.

1. Of, relating to, or concerned with the stars or constellations; stellar. 2. Measured or determined by means of the apparent daily motion of the stars: sidereal time.

sidereal, adj. meanings, etymology, pronunciation and more in the Oxford English Dictionary

The sidereal year is the time it takes for the Earth to complete one full orbit around the Sun, as measured against the fixed stars on the celestial sphere. In contrast, the tropical year is the time it …