How did the twenty-four solar terms come about?

The solar terms of 1 and 24 are the products of ancient farming civilization, which contains the long-standing cultural connotation and historical accumulation of the Chinese nation. It was originally formulated according to the shift of stars, and the ancients guided agricultural production according to the direction of the Big Dipper in the night sky. During the period of Emperor Wu of the Western Han Dynasty, the "twenty-four solar terms" were included in the taichu calendar as a supplement to guide the agricultural calendar, and the solar terms were measured in the Yellow River basin by the standard chart drawing method. The current "twenty-four solar terms" came from more than 300 years ago according to the degree of the yellow sun of the sun. In the historical development, the "24 solar terms" have been incorporated into the lunar calendar and become an important part of the lunar calendar.

2. According to the literature, four solar terms, midsummer, midsummer and winter solstice, appeared in the Central Plains of China in Shang Dynasty, and eight solar terms appeared in Zhou Dynasty. During the period of Taosi ruins more than 4,000 years ago, the Central Plains area has measured its position in the world with the soil regulation method (standard table) in Luoyi, Henan Province, and it has been designated as soil. The first of the 24 solar terms determined by Duke Zhou is the "winter solstice" determined by standard chart mapping, and is considered to be the first of the 24 solar terms. The essence of the method of Surveying Shadows by Soil Gauge is that "the tree is eight feet high, and the scenery is five inches long from summer to the sun (equivalent to no pole on the Tropic of Cancer); On the solstice of winter, the scene is one foot, three feet and five inches long (that is, an eight-foot high benchmark is erected). On the summer solstice, the shadow of noon is 65,438+0.5 feet, and on the winter solstice, the shadow of noon is 65,438+03.5 feet. " Measure the soil depth, correct the shadow, find the ground, and check at four o'clock. "In the Spring and Autumn Period, Shangshu recorded the solar terms. There were only four solar terms in Shang dynasty, while there were eight solar terms in Zhou dynasty. The names of the twenty-four solar terms first appeared in Liu An's "Instructions of Huainan Tian Zi" in the Western Han Dynasty, and the concepts of Yin and Yang, four seasons, eight places, twelve degrees and twenty-four solar terms were also mentioned in the preface to Historical Records Taishi Gong. In BC 104, taichu calendar written by Deng Ping set 24 solar terms in the calendar.