How is the size of the lunar month divided?
Related introduction:
The mid-year month of the lunar calendar is based on the length of 29.5306 days in the first lunar month, so the big month is 30 days and the small month is 29 days. In order to ensure that the first day of each month (the first day) must be a new moon, the arrangement of large and small months is not fixed and needs to be determined through strict observation and calculation. Therefore, it is common for the lunar calendar to be big or small for two consecutive months.
Extended data
The current leap day method of 97 in 400 years of Gregorian calendar is equivalent to the "leap week" in the ancient traditional calendar of China. Specifically, it is added to the year in which the number of AD years is divisible by 4 (except century year) and the year in which century year is divisible by 400.
When the taichu calendar Law was enacted in the Western Han Dynasty, it was stipulated that the month without neutral qi was a leap month, and this method has been used ever since. At this time, the new leap week is the natural result of more accurately determining the tropic year and the new moon. It is of little significance for arranging leap months. Since Li's Linde Calendar in Tang Dynasty, leap weeks are no longer fixed.
Its size and month are set strictly according to the moon phase, and are based on observation, not fixed.
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