The annual Dragon Boat Festival is coming. Astronomy experts say there is something special about this year’s Dragon Boat Festival, which is one of the last three dragon Boat Festivals of the 21st century.
The Dragon Boat Festival falls on the fifth day of the fifth month of the lunar calendar, but its date in the Gregorian calendar is very fluid. The reason for this change is the “leap month.”
Zhao Heng, an astronomy education expert and director of tianjin Astronomical Society, said that the traditional lunar calendar adopted in China for thousands of years is actually the yin-yang combination calendar, which takes into account both the solar calendar year directly related to the sun and the lunar phase changes. The average number of days in a 12-month period is 29.5306, and the total number of days in 12 months is 354 or 355, which is about 11 days different from that in a tropical year (about 365.25 days).
In order to solve the contradiction between the two, the ancients adopted the method of setting “leap month”. The current method of buying a leap in the lunar calendar is called a “leap month,” which means that every two to three years, a month must be added, known as a leap month. The rule of “leap” is based on the 24 solar terms.
The year of gengzi mouse is a leap year, adding a “leap April”. The leap April starts on May 23 and ends on June 20. As a result of the leap of April, the lunar calendar has since pushed back the date of festivals such as the Dragon Boat Festival by 18 days from last year. Last year’s Dragon Boat Festival fell on June 7. This year’s festival falls on June 25.
Zhao Heng said that in the 21st century, there have been three dragon Boat Festivals in the last 100 years: 2001, 2020 and 2058, all of which fall on June 25. The Dragon Boat Festival is not the latest to appear on June 25 in the Gregorian calendar, but on June 26 in the Gregorian calendar, as in 1906.