The earliest calendar in the world?

The lunar calendar takes the first month of the lunar calendar as the basic cycle and the movement of the moon as the astronomical basis, which has nothing to do with the movement of the sun. Lunar calendar, referred to as "lunar calendar" for short, is the earliest calendar in human history, which is mainly composed of calendar months and derived from calendar years. The lunar calendar is based on the cycle of the moon phases, that is, the time for the moon to orbit the earth once. This unit is called a month, and twelve months is a year. The "moon" mentioned here refers to the "moon", which is equal to 29.53059 days, nearly 29.5 days, 30 days for the big month and 29 days for the small month. There are six months every year, and the new moon is the first day of the month, totaling 354 days, but the actual length of the twelfth lunar month is 354.38+0 average solar days. The calculation of 0.367 1 is about equal to 1 1/30, so there are eleven leap years every thirty years (leap years have 355 days each year), and the average leap year is about once every three years.

Because the lunar calendar can't accurately reflect the cycle of seasonal changes, there is a difference of eleven days between the Gregorian calendar year and the tropic year, which is about once in thirty-three years, but the opposite is true in winter and summer in seventeen years. Can not meet the needs of agricultural production, and now it has been abandoned. The hijri calendar adopted by Muslims is such a pure lunar calendar. The era of the Jewish calendar is 376 BC1,afternoon 1 1,1and 1/3 minutes, and the average year is 12 lunar month (there are 353, 354 or 334).