Is there a simple method to calculate solar terms?

It has been introduced that there is a relatively fixed correspondence between the 24 solar terms and the solar calendar, that is, the first half comes from June 2 1 day and the second half comes from August 23, but this is extremely rough. If you want to know the date and time of each solar term every year, you must check the calendar. The exact date and time of the twenty-four solar terms are determined by complicated calculation, which is not suitable for introduction in this book. In order to meet the requirements of astronomy enthusiasts, this paper only introduces a simple method to calculate solar terms, but the calculation result of this method may have an error of several minutes or even ten minutes.

This method first needs to know the date and time of each solar term in a certain year of the Gregorian calendar, and then make a concrete calculation forward or backward on this basis.

Push back:

(1) If one year is a normal year and the second year is also a normal year, then the date and time of each solar term in the first year are added by 5: 49 to get the date and time of each solar term in the second year. It can be written as an expression:

(Ping Hou Ping) X solar terms = (Qian Ping) X solar terms +5: 49.

For example, from beginning of spring at 5: 56 on February 4th of 198 1 year (normal year), calculate the date and time of 1982 (normal year) in beginning of spring.

(1982) beginning of spring =( 198 1 year) beginning of spring +5: 49.

= 5:56+5:49 on February 4th.

= February 4th 1 1: 45

(2) If the previous year is a normal year and the second year is a leap year, the date and time of each solar term in leap year 1 and 2 months are the date and time of each solar term in the first year 1 and 2 months plus 5: 49. From March to 65438+February, 1 1 points shall be deducted from 18.

Namely: (leap after leveling) 3 ~ 65438+ February * solar terms = (before leveling) 3 ~ 65438+ February x solar terms ~ 18 hours 1 1 minute.

For example, the date and time of the vernal equinox 1980 (leap) can be calculated from the vernal equinox 13 on March 2 1 day.

(1980) vernal equinox =( 1979) vernal equinox-18 hours 1 1 minute.

= March 2 1,13: 22-18:11.

= 3 tablets for 20 days 19: 00 1 1.

(3) If the first year is a leap year and the second year is a flat year, the date and time of each solar term in 1 and 2 months of the flat year are leap years, and the corresponding solar term is deducted 1 1 min; From March to 65438+February, the date and time of each solar term is the corresponding solar term date of leap year, plus 5: 49. The expression can be written as:

(after leap) 1 ~ February x solar terms = (before leap) 1 ~ 2x solar terms-18 hours 1 minute.

(after leap) 3 ~ 65438+ February x solar terms = (before leap) 3 ~ 12x solar terms +5: 49.

Move forward:

(1) The method of calculating the date, time and algorithm of last year's solar terms from the average solar terms is opposite to that of next year. Namely:

(flat before flat) x solar terms = (flat after flat) x solar terms -5: 49.

(2) Calculating the solar terms of the last leap year from the average year is opposite to calculating the next average year from the leap year. Namely:

(leap before leveling) 1- February x solar terms = (after leveling) 1- February x solar terms+1 1 08 o'clock.

(Ping Qianping) 3-65438+ February X solar terms = (Houping) 3-65438+ February X solar terms -5: 49.

(3) The algorithm for calculating solar terms in leap year is opposite to that in the next leap year. Namely:

(before leap) 1 ~ February x solar terms = (after leap) 1- February x solar terms+18 hours 1 1 min.