How to calculate the exact time (accurate to 0.00 1 second) in the 24 solar terms? For mathematical calculation methods,

Accurate calculation time formula of 24 solar terms;

General formula of longevity -[y× d+c]-l

Y= the last two digits of the year, D=0.2422, L= the number of leap years, and C depends on the solar terms and year.

The current 24 solar terms are divided by the method of "fixing qi". The method of "fixing qi" is different from the ancient method of "bucket handle acupoints". Although the determination methods are different, the astronomical phenomena marked by them are the same. The "solid gas method" takes the summer solstice when the sun runs to 90 degrees of the yellow meridian, which is also the tropic of cancer when the sun points directly at the intersection. It takes the earth's revolution around the sun as a cycle.

The method of "fixing qi" divides the sun's annual motion trajectory into 24 equal parts, each of which is a solar term, and each solar term has three cycles. The ancients called solar terms "qi", and 24 solar terms were 24 qi, which were divided into solar terms and middle qi: the first qi at the beginning of each month was called "solar terms"; The second "Qi" in the middle of the month is called "Zhong Qi". In this way, there are 12 solar terms and 12 neutral terms throughout the year, which together are exactly "24 solar terms".