Why are the lunar dates in the perpetual calendar different from those in the old yellow calendar?

What you said may be that there is a discrepancy between beginning of spring and the Spring Festival.

This involves the determination of the starting time of lunar year.

Many people think that the first day of the first month is the first day of the Lunar New Year because the Gregorian calendar 65438+1 October1is the New Year.

The lunar calendar in our country is the lunar calendar. Is to consider the movement of the sun and the moon at the same time. Simply put, the year is determined by the sun; The "moon" is determined by the moon. In the lunar calendar, the 24 solar terms are the framework of the year, which is completely set according to the return of the sun. So basically, the Gregorian calendar date of each solar term is fixed. However, the lunar calendar days of solar terms are far apart. Every month in the lunar calendar is based on the moon's profit and loss, and the new moon is always on the first day. The beginning of a year is the beginning of spring.