Twenty-four solar terms refer to the specific festivals in the dry calendar that indicate seasons, phenology, climate change and the establishment of "December Construction". "Twenty-four solar terms" was originally determined by the Beidou bucket handle.
The "twenty-four solar terms" are divided by the method of "constant gas", that is, each solar term corresponds to a certain position reached by the earth every time it runs15 on the ecliptic; It divides the annual movement track of the sun into 24 equal parts, each15 is an equal part, and each equal part is a solar term, starting from the beginning of spring, ending in severe cold, and repeating.
Extended data
origin
In ancient China, the sundial was measured by Tugui, and the longest day shadow was defined as the "Solstice" (also called the Solstice, that is, the Taiyin, the Solstice and the Winter Solstice of the four elephants in Taiji map), and the shortest day shadow was the "Solstice" (also called the Short Solstice and the Summer Solstice). In spring and autumn, there is a day with the same length of day and night, which is called "vernal equinox" and "autumnal equinox", and there are many people of all ethnic groups.
In Shang dynasty, there were only four solar terms (four images, namely four seasons), but in Zhou dynasty, it developed to eight (eight diagrams), and in Qin and Han dynasties [3], the twenty-four solar terms were completely established. In BC 104, taichu calendar, written by Deng Ping, officially set the 24 solar terms in the calendar, and defined the astronomical position of the 24 solar terms.
The names of the twenty-four solar terms first appeared in Huai Nan Zi Tian Xun, and the concepts of Yin and Yang (the movement of the sun and the moon), four seasons (the four seasons), eight places (the gossip), twelve degrees (the hour) and twenty-four solar terms were also mentioned in the preface of Historical Records Taishigong. During the reign of Emperor Wu of the Han Dynasty, Luo Xiahong compiled the solar terms into the taichu calendar, and stipulated that the month without neutral gas was the leap month of last month.
Each of the 24 solar terms corresponds to the position reached by the sun for each movement15 on the ecliptic. Twenty-four solar terms are divided into 12 solar terms and 12 neutral terms, one by one. Twenty-four solar terms reflect the annual apparent movement of the sun, so the date of its western calendar is almost fixed. The solar terms in the first half of the year are on the 6th, and those in China are on 2 1 day, while those in the second half are on the 8th, and those in China are on the 23rd, which is not different1~ 2 days.
The naming of the 24 solar terms reflects the changes of seasons and climate. Beginning of spring, Vernal Equinox, long summer, Summer Solstice, beginning of autumn, Autumn Equinox, beginning of winter and Winter Solstice, also known as eight places, are eight key nodes to distinguish the influence of revolutionary movement on the earth; Sixteen items, such as Rain, Sting, Qingming, Grain Rain, Xiaoman, Mang, Xiaoshu, Dashu, Chushu, Bailu, Hanlu, first frost, Xiaoxue, Snow, Slight Cold and Severe Cold, reflect the subtle climate changes in the four seasons.
Baidu encyclopedia-24 solar terms