What is astronomical time and how to calculate it? How to compare

Fortune-telling time is astronomical time (depending on the longitude of the sun), while the time recorded in the average person's mind is clock time, that is, the average solar time in the artificially set standard time zone. If you were born at the beginning and end of a certain time, you will often make mistakes because of "depending on the sun time difference". First, the longitude difference between the standard time and the place of birth:

The world is divided into twenty-four time zones, with longitude divisible by 15 as the central meridian of the region, and each time zone accounts for 15 degrees. In the area east of the central meridian of the time zone, the time should be increased, and in the area west, the time should be reduced by 4 minutes.

China is divided into five time zones:

(1) Central Time Zone: East longitude 120 degrees is the central meridian.

(2) Longshu time zone: East longitude 105 degrees as the central meridian.

(3) New Tibet time zone: 90 degrees east longitude is the central meridian.

(4) Kunlun time zone: 75(82.5) degrees east longitude is the central meridian.

(5) Changbai time zone: the central longitude is 135( 127.5) degrees.

The "standard time" of a time zone is only the unified time of a large area, and it is only the "artificial" time observed by everyone, not the "local time (LMT)"-the real longitude time of every place in the time zone. This principle is used anywhere in the world to add and subtract the longitude of the birthplace and the standard time of the birthplace.

For example, the Central Plains time zone includes Inner Mongolia, Liaoning, Hebei, Shanxi, Shandong, Henan, Anhui, Jiangsu, Hubei, Hunan, Jiangxi, Zhejiang, Fujian, Guangdong, Hainan, Hong Kong, Macau and Taiwan Province Province. When the clock strikes 12 at noon in this large area, only the position on the east longitude 120 degree line is 12, and all other places are less or more than 12. For example, Hong Kong is located at east longitude 1 14 degrees 10 minutes, and 5 degrees and 50 minutes west of east longitude 1 1: 36: 40.

The astronomical time base is: (1) Earth rotation; (2) Earth's orbit around the sun; (3) The orbit of the moon around the earth. Therefore, astronomy defines several major years, months and days listed in the following table. Astronomical time, sun, moon, year, year, sun, moon, year, year, year, year, year, year, year, year, year, year, year, year, year, year, year, year, year, year, year, year, year, year, year, year, year, year, year, year, year, year, year, year, year, year, year, year, year, The true solar day is the time required for the true sun to continuously pass through the same meridian circle from east to west on the celestial sphere. Ping sidereal day is the time required for the Equinox to pass through the same meridian circle twice in succession from east to west on the celestial sphere. The real sidereal day refers to the time it takes for the real vernal equinox to continuously pass through the same meridian circle from east to west on the celestial sphere. The ratio of the average solar day length to the average sidereal day day length is1.002737909265+0.589 t×10-10; The ratio of the average sidereal day length to the average solar day length is 0.995438+04-0.586 t× 10. 7097+59T)+ 10- 12 The ratio of sidereal day length to the earth's rotation period is: 0.999999902902-59t×10-/2, where t is from1900. The new moon is the time required for the moon phase to change from the new moon to the new moon. The moon and the moon are the time it takes for the moon to pass a star twice in a row on the celestial sphere. Perigee month is the time required to pass perigee twice in succession on the moon. The intersection month is the time required for the moon to cross the ecliptic twice in a row on the celestial sphere. Returning to the moon is the time required for the moon's yellow meridian to be equal to the vernal equinox twice in a row. Their lengths are: 1 Wang Shuoyue =29.53059 flat solar day 1 sidereal month =27.32 166 flat solar day 1 perihelion month =27.55455 flat solar day 1 node month = 27.2. A sidereal year is the time it takes for the sun to pass a star twice in a row on the celestial sphere. The perihelion year is the time required for the earth to pass the perihelion twice in a row. The year of intersection is the time required for the sun to rise to the intersection point through the lunar orbit twice in a row on the celestial sphere. Julian year is a chronological method based on tropic year. The length of each year is: 1 tropic year =365.24220 mean solar day 1 sidereal year =365.25636 mean solar day 1 perihelion year =365.25964 mean solar day 1 node year =346.62003 mean solar day.