Are the 24 solar terms determined by the lunar calendar or the solar calendar?

24 solar terms is divided according to the position of the sun on the ecliptic (that is, the earth's orbit around the sun). Depending on the sun starting from the vernal equinox (longitude zero, at this moment the sun shines vertically on the equator), every advance of 15 degrees is a solar term; After running for a week, I returned to the vernal equinox, which is a tropical year, 360 degrees, divided into 24 solar terms, twice a month. It reflects the annual apparent movement of the sun, so the date of solar terms is basically fixed in the current Gregorian calendar, with the first half of the year being 6 days and 2 1, and the second half being 8 days and 23 days, with a difference of 1 ~ 2 days. Therefore, from this point, we can clearly analyze that although the 24 solar terms came from ancient China, their algorithms are basically consistent with the existing solar calendar. According to the position change of the sun on the ecliptic and the evolution order of the ground climate caused by it, the whole year is accurately divided into 24 equal parts, and each equal part is named.

Although the 24 solar terms, like the Gregorian calendar, are determined according to the position of the sun on the ecliptic, and the Gregorian calendar date of each solar term is basically unchanged, there will still be fluctuations for one or two days, because the time required for the earth to go around the sun is not exactly 365 days. Take beginning of spring as an example: beginning of spring is always between February 3rd and 5th in the solar calendar every year. However, in the lunar calendar, the date of solar terms is not easy to determine. Take beginning of spring as an example. It can be on the first day of February 15 of the 65438+ lunar calendar, or at the latest on the first day of 15. As an important basis for guiding agriculture, the 24 solar terms must be relatively accurate. So if we use the lunar calendar to divide it, it will inevitably bring great errors, and of course it will not play a guiding role.

Therefore, the 24 solar terms are divided according to the same principle as the solar calendar.