sidereal day
Quick Summary
A sidereal day is a unit of time used in astronomy, defined by the apparent motion of distant stars relative to Earth. It is the time it takes for a specific point on the celestial sphere, like the vernal equinox, to transit the upper meridian of a location twice. A sidereal day is approximately 23 hours, 56 minutes, and 4.1 seconds of mean solar time. This is nearly 4 minutes shorter than a standard solar day. Astronomers use sidereal time because it allows for consistent tracking of celestial objects, as stars transit the same meridian at the same sidereal time throughout the year. The difference between solar and sidereal days accounts for seasonal changes in visible stars and the necessity of leap years.12
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- day
The sidereal day is the time required for the Earth to rotate once relative to the background of the starsāi.e., the time between two observed passages of a star over the same meridian of longitude. The apparent solar day is the time between two successive transitsā¦
Read MoreThe sidereal day is the time required for the Earth to rotate once relative to the background of the starsāi.e., the time between two observed passages of a star over the same meridian of longitude. The apparent solar day is the time between two successive transitsā¦
Read More - hour
The hour of sidereal time, 1/24 of the Earthās rotation period relative to the stars, was about 10 seconds shorter than the hour of mean solar time.
Read MoreThe hour of sidereal time, 1/24 of the Earthās rotation period relative to the stars, was about 10 seconds shorter than the hour of mean solar time.
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