Definitions for

**"Sidereal Day"****Related Terms:**Sidereal time, Sidereal year, Sidereal month, Solar day, Equation of time, Lunar day, Sidereal, Solar year, Sidereal period, Solar time, Synodic, Solar noon, Synodic period, Mean solar time, Anomalistic month, Ephemeris time, Lunation, Tropical year, Month, Short-period comet, Day, Mean sun, Ephemeris, Solar maximum, Sun-synchronous orbit, Solar return, Solar minimum, Analemma, Diurnal motion, Synodic month, Precession of the equinoxes, Epoch, Solar cycle, Solar calendar, Lunar month, Solar chart, Orbital period, Oort cloud, Saros cycle, Apollo asteroid, Transit, Halley's comet, Elongation, Saros , Kepler's laws, Ecliptic, A.u, Full sun, Retrograde

The period of rotation of an object with respect to the stars. Compare this to a solar day, which is the period of rotation of an object with respect to the Sun. On Earth a sidereal day is 23 hours, 56 minutes and 4 seconds, while the solar day is 24 hours.

Twenty-four sidereal hours equal to 23 hours, 56 minutes and 4 seconds of clock time.

The length of a planet's rotation period relative to the stars.

a unit of time used in astronomy, equal to the period of time in which the earth makes one rotation relative to the stars. If we could view the earth from outside the Solar System, we would see that it actually completes 366.242 rotations during one year (one revolution around the sun). We only count 365.242 because one rotation is cancelled out for us by our tour around the sun. Thus the sidereal day, the average interval between two successive risings of the same star, is shorter than the mean solar day (see day) by 1/366.242. The sidereal day equals 23 hours 56 minutes 4.090 54 seconds, or 86 164.090 54 seconds. Like the regular day it is divided into 24 sidereal hours, each sidereal hour being divided into 60 sidereal minutes and each sidereal minute into 60 sidereal seconds. The sidereal hour equals 59 minutes 50.17 seconds; the sidereal minute equals 59.8362 seconds, and the sidereal second equals 0.997 270 second. Traditionally, observatories had clocks set to this sidereal cycle, and astronomers still use sidereal time in making telescope settings.

The rotation period of the Earth around its axis, relative to the Vernal Equinox. Slightly shorter than the actual rotation period, because of the precession of the Equinoxes.

the interval of time between two consecutive transits of the catalogue equinox. (See sidereal time.)

time between successive meridian crossings of a star. It is the true rotation period of a planet (on Earth, one sidereal day = 23 hours 56 minutes 4.09 seconds). Rotation rate of the Earth = 1° every 4 minutes (actually 3.989 minutes). The Earth's sidereal day is four minutes shorter than the solar day our clocks are based on so a star crosses the meridian 4 minutes earlier than it did the previous night.

the time for one complete rotation of the earth relative to a particular star, about 4 minutes shorter than a mean solar day

Duration of one rotation of the earth with a fixed stellar Point as reference, namely, the first Point of Aries.

The time required for Earth to revolve 360o with respect to a celestial object outside the solar system. About 23 hours 56 minutes duration in terms of solar time.

The time required for a complete rotation of the earth in reference to any star or to the vernal equinox at the meridian, equal to 23 hours, 56 minutes, 4.09 seconds in units of mean solar time.

A measurement of a day base on the rotation of the Earth relative to the celestial sphere. A mean sidereal day is 23 hours 56 minutes 4.1 seconds. This is opposed to a Solar day which measures the rotation of the Earth against the position of the Sun (24 hours).

The time it takes Earth to rotate once relative to the stars or 23 hours 56 minutes and 4 seconds, which is 4 minutes less than a solar day, since during one sidereal day the Sun also moves 1° east along the ecliptic, and Earth has to rotate 4 additional minutes to complete one rotation relative to the Sun in one 24-hour solar day.

Is the amount of time it takes the Earth to rotate 360 degree about its axis. It is about 1436.07 minutes.

The amount of time required for the Earth to rotate exactly 360 degrees about its axis with respect to the "fixed" stars. The Sidereal Day contains 1436.07 minutes. See also: Solar Day.

Twenty-four sidereal hours equal to 23 H, 56 M and 4 S of clock time.

the time for a planet or moon to rotate so that a distant star overhead is again overhead.

An apparent sidereal day is the time it takes for the Earth to turn 360 degrees in its rotation; more precisely, is the time it takes a typical star to make two successive upper meridian transits. This is slightly shorter than a solar day. Earth's orbit contains 366.25636042 sidereal days in a sidereal year appearing as 365.25636042 mean solar days.