sidereal

Of, relating to, or concerned with the stars or constellations; stellar.

Measured or determined by means of the apparent daily motion of the stars.

Pertaining or relating to the constellations or fixed stars; consisting of or constituted by fixed stars: as, the sidereal regions; sidereal calculations; a sidereal group or system.

Relating to the stars; starry; astral.

Measuring by the apparent motion of the stars; designated, marked out, or accompanied, by a return to the same position in respect to the stars

See under Clock, Day, etc.

time as reckoned by sideral days, or, taking the sidereal day as the unit, the time elapsed since a transit of the vernal equinox, reckoned in parts of a sidereal day. This is, strictly, apparent sidereal time, mean sidereal time being reckoned from the transit, not of the true, but of the mean, equinoctial point.