These three walls are Wei Zi Wall, Qiu Wall and Shi Tian Wall. Each wall is a relatively large sky area, which contains several (small) stars (or constellations). According to the records in Qing Hui Dian, the division of Gan, Shi and Wu is different. There are stars in the east and the west on every wall. It is like a wall, so it is called.
Ziweiyuan
Ziweiyuan is the central wall of Sanyuan, located in the center of the northern sky, so it is also called Zhonggong, or Ziweiyong. Purple means imperial palace, and most of the stars are named after official names. It is in the extreme center of the north, with 15 stars in the east and 15 stars in the west. These two bows combine to form a wall. According to the observation records of Emperor You of Song Dynasty, the whole Ziweiyuan consists of 37 constellations with 2 seats.
Taiweiyuan
Taiwei Courtyard is the upper wall of Sanyuan, located in the lower northeast of Ziwei Courtyard and south of Beidou. Covering the sky about 63 degrees, with Wudi as the center, * * * contains 20 constellations, 78 main stars and 65,438+000 additional stars. Including Virgo, Houpai, Lion and other constellations. Qiu means the government, and the star name is also the official name.
Tianshiyuan
The Shi Tian Wall is a three-dimensional lower wall, located in the southeast direction under the Wei Zi Wall, occupying about 57 degrees in the sky, which is roughly equivalent to a part of international common constellations such as the Five Immortals, the serpent and the snake, including 19 stars, 87 positive stars and 173 additional stars. It takes the throne as the center, forming a screen-like sector. Tian Wenzhi, Book of Jin, said: "The son of heaven leads princes to prosper the city." Therefore, the names of the stars are mostly articles and appliances, and the market names of commercial contents. For example, in Jin Zhi, it is said that the emperor's seat "represents yin and yang", the hoop and bucket "represent solid", and the bucket is used to measure liquid.
Four elephants
Black Dragon, Xuanwu, White Tiger and Suzaku are collectively called "Four Elephants". The ancients divided the 28 stars in the whole day into four parts according to the four directions of east, south, west and north, and each part contained seven stars. According to the shape of the seven stars in each part, these four parts are named by four similar animals, which are called four elephants or four places. The corresponding relationship is this: the seven stars in the east seem to fly in spring and early summer. Seven nights in Nanguan, in the cold winter and early spring, is like a suzaku in the sky, so it is called Nanguan suzaku. The seven nights in the west are called Xiguan White Tiger. Seven nights in the north are like snakes and turtles in the night sky in late summer and early autumn, so it is called Beiguan Xuanwu; There are many narratives about these four images in ancient Chinese books, such as Kao by Zhang Heng, Long Yuzi, Lingxian and Shangshu by Kong. Among them, the narrative in Lingxian is the most vivid. Zhang Heng wrote: "The black dragon is curled up on the left, the white tiger is fiercer than the right, Zhu is struggling ahead, and the turtle circle is in front." For example, Zhang Yi, Ren Wei's Records of the Heavenly Officials, Records of the Historians, Boya, and Huang Yuan's General Examination of Shangshu, etc. According to Shi's Classic, they are not four elephants, but divided into several small elephants, and there is no complete image in the west and north. The book says: "Female tortoise elephant." The records in Historical Records Tianguanshu are basically the same as those in Lingxian County, that is, black dragon, suzaku, white tiger and Xuanwu represent the stars of the four seasons respectively. According to the historian "Official Book", China astronomer Gaul designed a picture of the relationship between twenty-eight lodges and four elephants, which is very wonderful.