Are you born to consider the truth? between them

Apparent solar time: the time interval between the center of the sun's apparent circle going up to the sky twice in succession is called true solar day. 1 The true solar day is divided into 24 apparent solar hours ... and so on. This time system is called apparent solar time. Apparent solar time is measured by the hour angle of the center of the true sun's apparent circle, and its starting point is noon in apparent solar time. In our daily life, the customary starting point is midnight (noon), just 12 hour apart. Therefore, in order to be consistent with people's daily habits, the apparent solar time is defined as: the hour angle of the center of the true sun's apparent circle plus 12 hour. Because the apparent solar time is obtained by observing the center of the sun's apparent circle, it is also called apparent solar time, or simply apparent solar time.

Average solar time: Because the sun runs at variable speed on the ecliptic, and the ecliptic is inclined to the equator, the true solar days vary in length throughout the year, which is inconvenient to use in daily life. Astronomy assumes an imaginary point, starting from the vernal equinox and returning to the vernal equinox with the real sun every year; But it runs at a constant speed from west to east on the celestial equator. Such an imaginary point is called the flat sun. The interval between two consecutive passes through the upper meridian during flat solar time is called flat solar day. 1 flat solar day is divided into 24 flat solar hours ... and so on. This application system is called flat solar time, or peace time for short. Usually calculated from the sky under the mean solar time, the mean solar time is defined as: mean solar time plus 12 hours.

These factors should be considered when calculating eight characters.