Who knows the origin of the 24 solar terms Song Dynasty?

The sources of twenty-four solar term song are as follows:

1. In ancient China, the sundial was actually measured by earth gauge, and the longest shadow was defined as "solar day to day" and the shortest shadow was defined as "solar day to day". One day in spring and autumn is the same length of day and night, which is designated as "vernal equinox" and "autumnal equinox". There were only four solar terms in Shang dynasty, but it developed to eight in Zhou dynasty and was completely established in Qin and Han dynasties. In BC 104, the taichu calendar written by Deng Ping officially set 24 solar terms in the calendar, and defined the astronomical position of the 24 solar terms.

The naming of solar terms reflects three seasons, phenology and climate change. The reaction seasons are beginning of spring, Spring Equinox, Long Summer, Summer Solstice, beginning of autumn, Autumn Equinox, beginning of winter and Winter Solstice, also known as Eight; Phenological phenomena include fright, Qingming, Xiaoman and Miscanthus. Rain, Grain Rain, little summer, big summer, early summer, white dew, cold dew, first frost, light snow, heavy snow, slight cold and severe cold are the responses to climate change.

Solar term Song: Spring rains shake the valley in spring, summer is full and summer is hot, autumn is cold and frost falls, winter is snowy and winter is chilly.