Introduction to lunar calendar

In astronomy, the lunar calendar mainly refers to the calendar arranged according to the moon phase cycle. The calendar in which the moon orbits the earth once (with reference to the sun, the moon actually travels more than once) 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 the process of calendar development and evolution, the emergence of 24 solar terms was used to guide agricultural production scientifically, and the lunar calendar (Han calendar) was formed. Although the lunar calendar and lunar calendar are commonly known as lunar calendar, ancient calendar, Han calendar, summer calendar and old calendar, there are differences between lunar calendar and lunar calendar (Han calendar). The traditional summer calendar (Han calendar) is actually a kind of yin-yang calendar. On the contrary, the Islamic calendar is a pure lunar calendar. Lunar calendar is one of the traditional calendars in China, also known as lunar calendar, ancient calendar, Han calendar, yellow calendar, summer calendar and old calendar. The lunar calendar is usually called the lunar calendar, which is based on the laws of the moon's motion: the orbit of the moon is called the white road, and the white road and the ecliptic road are two circles on the celestial body, which intersect at five degrees and nine minutes. The moon goes around the earth once, and it appears on the ecliptic for two weeks, and the calendar is twenty-seventh. Only when the moon revolves around the earth, the position of the earth changes, counting forward more than 27 degrees, and the moon runs at the speed of 13 degrees 15 minutes every day, so it takes 29 days 12: 44: 2.8 to return to the moon. This is called "the first moon", which is called a month by custom, meaning