The current "twenty-four solar terms" come from the "constant air method" concluded more than 300 years ago (it has been used since 1645). It is determined according to the position of the sun on the ecliptic, that is, on a 360-degree circle "ecliptic" (the sun's apparent path on the celestial sphere for one year), it is divided into 24 equal parts, each part/kloc-.
With the spring as the starting point of 0 degrees (but beginning of spring is still used to ranking first), it is arranged according to the degrees of the Yellow Meridian. When the ecliptic of the sun reaches 15, it is the Qingming intersection. "Qingming" means that the climate is warm, plants sprout, apricots and peaches are in full bloom, giving people a fresh, clear and prosperous feeling everywhere.
Tomb-Sweeping Day's integration of natural solar terms and humanistic customs is a combination of humanistic and natural conditions, which fully embodies the Chinese ancestors' pursuit of harmony between heaven, earth and people, pays attention to conforming to the right time, place and people, and follows the laws of nature. Tomb-Sweeping Day is rich in festivals and customs. Grave-sweeping and hiking are two major themes of etiquette and custom in Tomb-Sweeping Day. The two traditional themes of etiquette and custom have been passed down in China since ancient times and have never stopped.
Extended data
Tomb-Sweeping Day is one of the twenty-four solar terms in the trunk and branch calendars, which indicates the change of seasons. At this time, it is a good time for outing in the suburbs (spring outing) and Qingming (grave-sweeping sacrifice). The old and the new spit out the old, the temperature rises, everything is clean and tidy, and the earth presents a quiet image of spring.
Tomb-Sweeping Day originated from the ancient Spring Festival, which has both natural and humanistic connotations. It is not only a natural solar term, but also a traditional festival. Tomb-Sweeping Day is a traditional major Spring Festival. It is a fine tradition of the Chinese nation for thousands of years to sweep graves and cherish the memory of ancestors. It is not only conducive to promoting filial piety and family memory, but also conducive to promoting the cohesion and identity of family members and even the nation.
Baidu Encyclopedia-Tomb-Sweeping Day