How is the time in beginning of spring calculated?

The spring time algorithm is as follows:

Beginning of spring is calculated according to the ecliptic. When the bucket handle of the Big Dipper points to the shade, it is the node of beginning of spring, that is, when the sun reaches longitude 3 15. "beginning of spring", one of the twenty-four solar terms, corresponds to a certain position reached by the earth every time it runs 15 on the ecliptic, which reflects the influence of the sun on the earth and belongs to the solar calendar category.

The earth's orbit around the sun was named "ecliptic" by the ancients, also known as "solar ecliptic". The ecliptic is divided into 24 equal parts, separated by 15, forming 24 solar terms. 24 solar terms is actually 24 solar terms, with 2 solar terms per month. Each solar term has three cycles, and each cycle is five days. When the sun reaches longitude 3 15, it is the beginning of the vernal equinox.

The custom of early spring:

Beginning of spring is also called "Da Chun", "beginning of spring" and "beginning of spring". This festival, like many festivals, has many folk customs, such as celebrations and activities to welcome spring, "shooting cows" in spring, and eating spring cakes, spring vegetables and radishes.

According to historical documents, the Spring Festival ceremonies in China were all grand. At this time, beginning of spring has gone beyond the function of the 24 solar terms of the lunar calendar to express only festivals and climate, and has been regarded as a festival, so many activities and folk customs around beginning of spring have evolved in history.