astronomical day的意思|示意

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Astronomical days are important astronomical times that are used to evaluate and measure the length of daylight and darkness. They are commonly used in astronomy to calculate the time of astronomical events such as solar eclipses and lunar eclipses.

An astronomical day is the amount of time it takes for one rotation of approximately 24 hours. This period of time is also known as a sidereal day. This rotation is measured from the reference point of the vernal equinox, which is the point of the sky where the Sun crosses the celestial equator from south to north each year.

Basically, the length of an astronomical day is based on the amount of time it takes for Earth to rotate on its axis. This can be calculated by using the International Atomic Time (TAI) system. The length of an astronomical day is slightly different in different areas of the world because of Earth's elliptical orbit around the Sun.

In astronomy, astronomical days are used to measure the length of daylight and darkness and to calculate the time of astronomical events. However, they are also used in some cases to measure the length of the day or night in entities such as a national park or city. This can be used in the calculation of certain types of astronomical events that occur in certain locations such as a solar eclipse or a transit of a planet across the Sun.

In summary, astronomical days are significant astronomical times used to measure lengths of daylight and darkness. They are used in astronomy to determine the time of astronomical events as well as in some cases for the measurement of the length of daylight or darkness in certain locations.