Calculated monthly by solar terms

The invention of leap moon embodies the wisdom of the ancients.

With the setting of leap month, the traditional calendar in China has been used for thousands of years.

Then, let's learn about the laws of the lunar leap month.

Leap moon refers to a phenomenon in the lunar calendar. The lunar calendar arranges the big moon and the small moon, that is, the moon, according to the full and short moon. The length of a moon is 29.5306 days, which is the cycle of the moon's profit and loss. According to the lunar calendar, there are 30 days for the big moon and 29 days for the small moon, and a year is 12 months * * 354 days. The lunar month has no seasonal significance, so just after 17, the date of the lunar calendar will be reversed with the seasons. For example, one year's New Year is spent in the snow, and after 17, the vermicelli will be shaken to celebrate the New Year. The use of such a calendar naturally cannot meet the needs of agricultural production, so the lunar calendar in China has been in parallel with the 24 solar terms since the Qin and Han Dynasties, and the 24 solar terms are used to guide agricultural production.

Twenty-four solar terms can be divided into two groups: "solar terms" and "middle qi": the ancients regarded every 30 degrees from the slight cold as a solar term; Starting from the winter solstice, the meridian of the Yellow River is a neutral gas every 30 degrees, with 12 solar terms and 12 neutral gas in a year. 12 solar terms divide a year into 12 months, and each month has a solar term and a neutral atmosphere. Solar term is the starting point of solar term month; Zhongqi is the midpoint of the festival. The traditional calendar in China does not adopt the method of day-to-day and month-to-month sequence and long-term arrangement of big month, small month, normal year and leap year, but emphasizes the calculation from year to month. The state sets up special institutions to calculate calendars.

First, set the date order according to the moon phase. It calculates the date and time of the conjunction of the sun and the moon one by one, and the first day of each month is the date of the conjunction; Determine the size of last month according to the number of days included in the second conjunction. If the interval between this new moon and the next one is 30 days, then this month is the big moon; If it is only once every 29 days, it is an abortion.

Second, set the order of the month and be neutral. First of all, the calendar month and leap month are distinguished by whether the calendar month is neutral or not. We know that there are 12 neutral gases in a tropical year, but it contains 365.2422 ÷ 29.5306 =12.3682 lunar months. After several calendar months of rotation, there must be a calendar month without neutral gas. "Han Shu Li Biao" contains: "If the new moon declines, it is called leap moon". This month without neutrality is a leap month. When the previous calendar day is a few months, it is a leap month. For example, the leap month in 1984 appears after October of the old calendar, so it is called "leap October". Leap months are calculated, not fixed in the monthly order of the year. In addition to 1 1 month,1February and the first lunar month, leap month is possible, and it is the seventh leap month in the nineteenth year.

Conclusion: To sum up, leap year is a phenomenon in the solar calendar, which is fixed in February and 29 days longer than normal. Leap month is a phenomenon in the lunar calendar. There is a leap month, and the lunar calendar of that year has 13 months, which is called leap month year. A leap month has 384 days.