Why is the winter solstice between February 22nd and 23rd in Gregorian calendar 10?

In ancient China, there was no fixed date from winter solstice, so it was called "solar term of life".

As early as more than 2,500 years ago in the Spring and Autumn Period, China had determined the "winter solstice" by observing the sun with the soil return, which was the earliest of the 24 solar terms.

The winter solstice is a solar term divided by astronomy. On the day of winter solstice, the sun is at 270 degrees of the yellow meridian.

Why is the winter solstice defined according to the solar calendar?

The winter solstice, also known as the Winter Festival, according to the traditional calendar of China, takes five days as the waiting period, three days as a section or breath, and a year is divided into twelve sections and twelve qi, which are collectively called twenty-four solar terms. This is the solar term used to study the date selection, which is based on the solar term of the lunar calendar, and the so-called lunar calendar is a combination of the solar calendar and the lunar calendar, which refers to the twenty-four solar terms (the solar cycle is divided into twelve stages, and the solar term refers to the solar term). ), the lunar calendar is a pure month (according to the cycle of the moon). ), the date coincides with the Gregorian calendar1February 2 1 day or 22nd.

According to the position of the sun on the ecliptic, the solar calendar divides a year into 24 equal parts, that is, the ecliptic is divided into 24 equal parts, and each equal part accounts for 15 degrees of the ecliptic. Because the time required for the sun to pass through each bisection is almost equal, the Gregorian calendar dates of the 24 solar terms are roughly the same every year.