Which dynasty did the twenty-four solar terms originate from?

Twenty-four solar terms originated in the Yellow River Basin. As early as the Spring and Autumn Period, the four solar terms were defined as mid-spring, mid-summer, mid-autumn and mid-winter. After continuous improvement and perfection, they were completely established in Qin and Han Dynasties. In BC 104, the astronomical position of the twenty-four solar terms was officially determined in taichu calendar written by Deng Ping.

There are two main methods for the ancients to calculate and determine the twenty-four solar terms: one is called equal division method, which divides a year into twenty-four equal parts, that is, 365.2422 days /24 = 15.2 18 days, that is, the average interval between two solar terms is 15 days; The other is called "the method of regulating qi". Because the sun moves unevenly on the ecliptic every day, it moves faster in winter and slower in summer. In this way, the method of equal share is unreasonable. The ancients created a method to determine the specific date of solar terms by fixing the qi, so that the vernal equinox and autumnal equinox were divided into 24 sections on average, distributed in December of the lunar calendar and the first month of each month. There are twelve solar terms such as beginning of spring, Jingzhe, Qingming, Changxia, Mangzhong, Xiaoshu, beginning of autumn, Bailu, Hanlu, beginning of winter, Heavy Snow and Slight Cold. Mid-month is called "Zhongqi", which includes rain, vernal equinox, Grain Rain, Xiaoman, summer solstice, big trees, early trees, autumn equinox, early frost, light snow and winter solstice.