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 …

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

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

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.

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

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...

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.

Nov 1, 2025 · (astronomy) Relating to a measurement of time relative to the point of the vernal equinox.

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

Definition of sidereal adjective in Oxford Advanced Learner's Dictionary. Meaning, pronunciation, picture, example sentences, grammar, usage notes, synonyms and more.