Have you ever met the Mid-Autumn Festival in 38 Teachers' Days?

On September 10, the Mid-Autumn Festival arrived as scheduled. Coincidentally, today is also the 38th Teachers' Day in China. It is a rare coincidence that these two festivals occur on the same day. There are only three festivals in this century, namely, 2022, 204 1 year and 2079.

According to the China lunar calendar, the big moon has 30 days, the small moon has 29 days, and the cumulative 12 months is 354 days or 355 days. In the Gregorian calendar, one revolution of the earth around the sun is the tropic year, with 365 days in a normal year and 366 days in a leap year. The difference between them is about 1 1 day.

In order to make up for the number of days different from the tropical year, so as to avoid the serious disconnection between the month and the season, the adjustment method is to arrange 13 months in some years, and there are two identical months, which are called "fixed leap". The rules for fixed leap are based on 24 solar terms.