How to calculate the exact time in beginning of spring?

Beginning of spring's exact time calculation formula: [y * d+c]-L. Interpretation of the formula: the last two digits of the year are multiplied by 0.2422 plus 3.87, and the whole number is subtracted from the leap year. 2 1 century c value =3.87, and in the 22nd century c value =4. 15.

Beginning of spring is the first of the twenty-four solar terms, and it was included in the first month solar terms in the official yearbook of Ming and Qing Dynasties. The arrival time is on February 3-5 of the Gregorian calendar every year (around the first day of the first lunar month), when the sun reaches 3 15. Beginning of spring is one of the important traditional festivals of the Han nationality. "Li" means "start". Since the Qin Dynasty, China has always regarded beginning of spring as the beginning of spring. Beginning of spring is divided from astronomy, with spring flowers and flowers; Spring is growth, cultivation and sowing. The period from the beginning of the Spring Festival to the long summer is called spring.