What is the stellar time?

sidereal time refers to the length of days and other time measurement with respect to stars other than our sun. While the solar day lasts 24 hours, the stellar day is about four minutes shorter. In everyday life, solar time is always used, but astronomers often consider it useful to use sidereal time as it expresses the apparent movement of stars in the sky, as observed from the ground. The word "sidereal" comes from the Latin word sider , which means "star". In one day, the Earth moves a small part of its orbit around the Sun and slightly changes the apparent angle at which the sun points on the ground. This little adding about one degree to the angle of the sun means that the Earth must turn another four minutes to "catch up" where the sun shone before one rotation.

However, the stars other than our Sun are mostly very distant, it only takes a full rotation of 360 degrees until the distant star returns at its starting point above the ground. This 360 degree rotation is called Star Day and TRVá 23 hours, 56 minutes and four seconds. On the solar day, the Earth rotates about 361 degrees on its axis and lasts for 24 hours.

Astronomers often use stellar time because they look at how long it takes for the Earth to turn, with respect to distant stars, rather than the sun. Sidereal Time gives us a way to measure time that does not depend on the sun. This eliminates a slight mathematical complication and focuses solely on how long it takes for the Earth to turn 360 degrees with respect to the stars.

The astronomer is a map, divided into 24 hours. Sidereal Time helps these scientists to determine where the star or set of Stars is at any time. The difference between solar and star time is not over an hour or a day, but contributes to a very large difference for months and years. This can be observed without a telescope. If one was looking or photographing the night sky at the same time every night, he would notice that Hhorses as a whole shift to the west over the course of time.