What is the lunar calendar?

Lunar calendar, also known as summer calendar, lunar calendar and old calendar, is one of the traditional calendars in East Asia. The lunar calendar belongs to a kind of lunar calendar, and an average calendar month is equal to a new moon. However, the leap month is set to make the average calendar year a tropic year, and the 24 solar terms are set to reflect the changing characteristics of the seasons (the annual movement of the direct point of the sun), so there is also a solar calendar. Today, almost all Chinese in the world, as well as countries such as North Korea, South Korea, Vietnam and early Japan still use the lunar calendar to calculate traditional festivals such as Spring Festival, Mid-Autumn Festival and Dragon Boat Festival. Because this calendar is said to have originated in the Xia Dynasty, it is called the Xia calendar. The summer calendar has an auxiliary part-solar terms. Solar terms, if counted as calendars, are complete solar calendars. Solar terms are related to the position of the earth around the sun, not to the moon. The solar term begins in the beginning of spring, and a solar year is the time between two beginning of spring, about 365.422 days. According to the position of the sun, a solar year is divided into 24 solar terms to facilitate agricultural planting and other activities. The calendar year of the summer calendar is heavenly stems and earthly branches collocation, with a cycle of 60 years. Years are divided into normal years and leap years. Normal year 12 months; Twelve months in leap year plus one leap month, a total of thirteen months. A month is divided into a big month and a small month, with a big month of 30 days and a small month of 29 days. Which month is big and which month is small in a year is different from year to year, which is determined by calculation. There are 354~355 days in a normal year and 383~384 days in a leap year. Because the number of days in a normal year is about eleven days worse than that in a solar year, the method of setting leap years (that is, twelve normal months plus one leap month) is adopted, so that the average number of days in these years is the lunar calendar.

The amount is close to 365.2422 days. Since the tropic year of 1 is 12.368 moons, and 368/ 1000=46/ 125, 46 leap years will be set in 125 years. However, due to the complexity of this jump, it is estimated that 7/ 19 is closest to 0.368. So generally speaking, 19 has seven leap months, and the year with leap months is 383 days or 384 days.

The lunar calendar in astronomy mainly refers to the calendar arranged according to the moon phase cycle. The calendar of the moon's one-week orbit around the earth (taking the sun as the reference object, the actual moon's orbit is more than one week) is January, that is, the first month of the lunar calendar is used as the basis for determining the calendar month, and a year is twelve calendar months. In agrometeorology, the lunar calendar is commonly known as lunar calendar, lunar calendar, ancient calendar and old calendar, which refers to the traditional summer calendar in China. Astronomically speaking, the summer calendar is actually a kind of lunar calendar.