The origin of leap month in lunar leap year

How to calculate the origin of leap month in lunar leap year

In the China lunar calendar, a year with a leap month is called a leap year.

The general year is 12 months, 354 or 355 days, and the leap year is 13 months, 383 or 384 days. As a kind of lunar calendar, the number of days per month depends on the monthly loss, and the time of one year is based on 12 months. In order to close the earth's cycle around the sun, that is, the tropic year, one month is added every two to four years, and the added month is a leap month, so the leap year of the lunar calendar is 13 months.

The origin of leap year in Gregorian calendar

In the Gregorian calendar (Gregorian calendar), a year with leap days is called leap year, which is generally 365 days and 366 days. Because the earth's orbit around the sun is 365 days, 5 hours, 48 minutes and 46 seconds (365. 242 19 days) is the tropic of cancer, and the Gregorian calendar sets a year as 365 days.

The remaining time is about one day in four years, plus February, so the normal year is 365 days, February is 28 days, leap year is 366 days, and February is 29 days. Therefore, there are 97 leap years every 400 years, with an additional day at the end of February, and leap years have 366 days.

Calculation method of leap year: the number of years in the calendar year can be divisible by four, which is a leap year; Divided by 100 but not divided by 400 is a normal year; Leap years can be divisible by 100 or 400. For example, 2000 is a leap year, but 1900 is not.

What are the lunar and solar calendars?

The sun is "yang", and the calendar based on the apparent movement of the sun is called "solar calendar";

The moon is "cloudy", so the calendar based on the apparent motion law of the moon is naturally called "lunar calendar".

Lunar calendar-the moon goes around the earth in January.

The lunar calendar determines the moon according to the law of its movement: the orbit of the moon is called the white road, and both the white road and the ecliptic road are two great circles on the celestial body, which intersect at five degrees and nine minutes. The moon goes around the earth once and appears on the ecliptic twice. The calendar on the 27th is 7 hours and 43 minutes 1 1.5 seconds, which is the time required for the first anniversary of the moon's revolution, and is called "the moon".

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

The method of determining the month in the lunar calendar is given by the cycle of the first lunar month, which is the first day of the first lunar month. The first lunar month is about 29 and a half days long, so the first lunar month is 30 days and the second lunar month is 29 days.