Why is there a run in May?

Lunar calendar 1998 has a "leap may", and the reason starts with 1 calendar. At present, the solar calendar and lunar calendar used in most parts of China are also called Gregorian calendar, and the earth's orbit around period of revolution is 365.2422 days a year. The lunar calendar, also called the combined calendar of yin and yang, is based on the full and short periods of the moon of 29.5306 days, taking into account the actual changes in cold and summer. The lunar year is 12 months, accounting for 354 days, less than the sun 1 1 day. At this rate, it is difficult to correspond the month with the season. For example, the Spring Festival is celebrated in dog days, and the dragon boat race is held in winter. In order to synchronize the lunar calendar with the solar calendar in season, the lunar calendar adjusts the surplus and deficiency by adding leap months, which is stipulated to come every two or three years. In the year with leap month, the lunar calendar is 13 months. So, which month is the leap month? Our ancestors divided a year into 24 solar terms. The former one is called "solar terms" and the latter one is called "zhongqi". Solar terms and neutral gas are arranged in monthly order. The average interval between two adjacent solar terms or two neutral qi is 30 and a half days, while the lunar month is only 29 and a half days (29.5306 days). In this way, it is necessary to postpone the solar terms and neutral momentum for a day or two next month. At some point, the neutral atmosphere will move to the end of the month instead of the middle of the month, and the next neutral atmosphere will be at the beginning of next month. In this way, there is only one solar term in the middle of the month and there is no neutral atmosphere. According to the lunar calendar, any month with only solar terms and no neutral atmosphere cannot be independent as a month, but can only be regarded as a subsidiary of the previous month-leap month. 1998 The month after May in the lunar calendar (June 24th to July 22nd in the solar calendar) has only one solar term, so it is designated as the subsidiary of May.

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