Time difference of world time zone in astronomical calendar

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". 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 Plains Time Zone (East Eighth District): the central meridian is East longitude 120 degrees.

(2) Longshu Time Zone (East Zone 7): the central meridian is East longitude 105 degrees.

(3) New Tibet Time Zone (East Sixth District): 90 degrees east longitude is the central meridian.

(4) Kunlun Time Zone (East Zone 5): 75 degrees east longitude is the central meridian.

(5) Changbai Time Zone (East Zone 9): the central meridian is east longitude 135 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.

Mean solar time and apparent solar time

The "average time of the sun" with a clock time of 24 hours per day is artificially set, and it is assumed that the orbit of the earth's rotation and revolution around the sun is a perfect circle, which is just the "unified" time set by the government for the convenience of administrative measures. In fact, because of the yellow equator, the rotation and revolution of the earth are not 24 hours every day of the year. Only April 25th, June 14, September 1 and February 24th of the solar calendar are exactly 24 hours, and the other 36 1 days are not. This error is called "apparent solar time difference". The world nautical calendar indicates the time difference between the true solar day and the average solar day every day. There is also a kind of "wartime time" in artificial time, which is also called "daylight saving time" and "daylight saving time" in some countries and local governments. Because of the early sunrise, late sunset and long days in summer, in order to make full use of sunlight and save electricity, the work and rest time is advanced by one hour (clocks and watches are set forward by one hour). Because of the above three time differences, it is not easy to get an accurate astronomical birth time. It is especially difficult to calculate the horoscope of foreigners, because in some areas, it is winter time, or Greenwich Mean Time (GMT), or the local time system is not uniform, so life scientists should first ask the time system in this area to avoid mistakes.

If the birth time is at the junction of solar terms or children's day, it is necessary to accurately calculate the time difference, otherwise not only the time is wrong, but also the birthday, birth month and birth year may be wrong because of an incorrect time.