Chapter 51 Section 1 Observatory

Legend has it that the observatory in the Xia Dynasty was called Qingtai, in the Shang Dynasty it was called Shentai, and in the Zhou Dynasty it was called Lingtai. There is a poem called "Lingtai" in "Poetry Daya", which tells that King Wen of Zhou once built a Lingtai in the western suburb of Fengyi. The platform is two feet high and 420 steps in circumference.The observatory before Zhou was mainly set up to worship the sun and the moon, so the observatory is just a platform higher than other buildings, and the site of the observatory is generally chosen in a flat and open area.

Most emperors in ancient China boasted (xu Xu) that they were "ordered by the sky", and believed that changes in celestial phenomena were closely related to their own dominance.Of course, they hope that the "information" from the sky will only be passed on to themselves, so they always have a firm grasp on the astronomical observation agencies, and they are only allowed to build observatories in the imperial city.But sometimes, when the central power loses control, the vassal states will ignore the ban and set up platforms one after another.In the Spring and Autumn Period, the State of Lu established its own observatory called Guantai.

Later, due to the increase in astronomical observation items and frequent sacrificial activities, the venues for the activities needed to be separated, and the sacrificial activities were held in a building called Mingtang, while the observatory was dedicated to astronomical and meteorological observations. According to historical records, in the Western Han Dynasty, an observatory was built on the outskirts of the capital Chang'an, which was also called Qingtai at first, and later changed to Lingtai.Astronomical and meteorological instruments such as armillary spheres, copper watches and Xiangfeng Tongwu are placed on the stage.In the Eastern Han Dynasty, Emperor Guangwu of the Han Dynasty built a Ming Hall and a Lingtai near Pingchang Gate in Luoyang City in the first year of Zhongyuan (AD 56).There are walls on the east and west sides of Lingtai, and there is a square high platform in the center of the wall, which is a place for observing astronomical phenomena.There are more than 10 houses around the high platform, where observers live and work.From the second year of Yuanchu (115 AD) to the second year of Yangjia (133 AD), the astronomer Zhang Heng was entrusted with the post of Taishi Ling twice, directly in charge of the observation work of Lingtai.The Lingtai of the Eastern Han Dynasty was still in use during the Three Kingdoms and Western Jin Dynasties, and it was not abandoned until the Northern Wei Dynasty. The Lingtai site was excavated in Yanshi County, Henan Province in 1974.The remaining platform foundation is made of rammed earth, about eight meters high, covering an area of ​​44,000 square meters.

The most important observatory on the outskirts of Chang'an in the Tang Dynasty was Yangguantai, also known as Sitiantai, which was directly under the supervision of Taishi. Astronomer Li Chunfeng made observations here.In the mid-Tang Dynasty, a viewing platform was built for astronomers in Jixian Academy.In addition, there is a Qingtai near Xianyang, Shaanxi Province, which is specially used for divination by astronomer Xue Yi.During the Sui and Tang dynasties, it was a fashion that the emperor not only established an observatory in the suburbs of the capital, but also set up an observatory in the inner courtyard of the palace.

During the Northern Song Dynasty, when the country was strong and the technology was advanced, four observatories were set up in Bianjing (now Kaifeng, Henan), of which the Yuetai of the Sitianjian and the waiting platform of the Hanlin Astronomical Academy in the Forbidden City were the main observatories.The two instruments are identical and are used to compare and check the measurement results.When there are abnormal astronomical phenomena, the two stations must check each other and report at the same time to prevent misreporting or fraud.The four observatories are all equipped with large armillary spheres, each made of 20,000 jin of copper.In addition, the Song government also set up a calibration center to check the accuracy of the armillary sphere and the missing engraving.After the imperial court was forced to move to the south, two more observatories were built in Lin'an (now Hangzhou), one was the Tiantai of the Taishi Bureau, and the other was the Secretary's Provincial Testing Institute.Regarding the architectural layout of the observatory in the Song Dynasty, we can only get a rough idea of ​​it from an illustration in a mathematics book in the Southern Song Dynasty (see Figure 17).

The Jin Dynasty established its capital in Yanjing (now Beijing) and established an observatory.Since the Jin people came from culturally backward areas and did not have sophisticated observation instruments, all the instruments and books of the Northern Song Dynasty were moved northward.However, the armillary sphere is designed according to the geographical latitude of Kaifeng and cannot be used in Beijing. Before Yuan people settled in Dadu (today's Beijing), a Huihui Observatory was established in Shangdu (the former site is on the north bank of the East Lightning River in Zhenglan Banner, Inner Mongolia), presided over by Zamarudin, a native of the Western Regions.The Huihui Observatory uses Arabic astronomical instruments to measure and compile various tables of the Arabic astronomical system, becoming the research center of Arabic astronomy in East Asia.From the description of Arabic astronomical instruments in historical books, it can be inferred that the scale of Huihui Observatory will not be too small.

In Gaocheng Town, Dengfeng County, Henan Province, there is a strange building. The house is not like a house, and the tower is not like a tower. A long "road" extends northward under the tall building. This is Dengfeng, which was built in the early Yuan Dynasty. observatory.It is said that the original site of the observatory was used for astronomical observation as early as the Zhou Dynasty.The local people still call it "Zhou Gong Observation Platform" until now.According to legend, during the Kaiyuan period of the Tang Dynasty, when Yixing and Nangong Shuo[yueyue] and others conducted the national astronomical geodetic survey, a stone watch was erected here with "Zhougong Measuring Platform" engraved on it, which seems to be true. "Scenery" connects with "shadow".The viewing platform is the imaging platform.The building itself of the observatory is a wonderful watch: the door in the center of the high platform is used as the end of the watch, and the "road" is paved with 36 stone slabs, which is used as a watch. Such a large watch is a masterpiece of Guo Shoujing.The existing Dengfeng Observatory was renovated in the Ming Dynasty. It is 31.19 meters long and 9.46 meters high. There are two rooms attached to the platform, but the room is empty and there are no instruments left.Dengfeng Observatory is not only the earliest surviving observatory in China, but also one of the oldest observatories in the world.In the Yuan Dynasty, there were 27 official astronomical sites like the Dengfeng Observatory, which were distributed across the country from 15° north latitude to 63° north latitude.

Sitiantai, the main official observatory of the Yuan Dynasty, was built in the southeast of the capital city. It was completed in the 16th year of the Yuan Dynasty (1279 AD), and was destroyed by war more than 300 years later.Through the narration in the "Taishi Yuanming" of the Yuan Dynasty, we can understand the basic layout of Sitiantai and restore it into a map (see Figure 18).Si Tiantai is seven feet high and surrounded by walls, which are 200 steps long and 150 steps wide.The whole building is divided into three floors, the lower floor is the office room, Taishi Ling and other officials are in the south room, the calculation bureau is in the east room, the test bureau and leak engraving bureau are in the west room, and the auxiliary staff are in the north room; the middle floor has eight rooms for storage. Books, instruments, etc. are placed; the upper floor is an open-air platform, equipped with instruments such as Jianyi, Yangyi, Guibiao and Linglongyi, and the printing calendar work bureau is also located on the upper floor.Sitiantai was one of the most advanced observatories in the world at that time, comparable to the Malaga Observatory in Central Asia.

In the eighteenth year of Hongwu in the Ming Dynasty (1385 A.D.), an observatory was built on Jiming Mountain in Nanjing. The instruments on the platform were from the Yuan Dynasty. In order to make the instruments suitable for observation in Nanjing, the instruments were modified.At the same time, the Huihui Star Observatory was built on Yuhua Terrace in Nanjing, and the instruments used were all Arabic instruments from the original Shangdu Observatory. The Beijing Ancient Observatory is the official observatory of the Ming and Qing dynasties. It has a history of 544 years. It is located next to the Jianguomen overpass in Beijing and is well preserved.Most of the instruments placed on the observatory were designed by Jesuit missionaries. In addition to some Chinese characteristics in shape, the structure and craftsmanship all reflect the level of European instrument manufacturing at that time.Astronomers in the Qing Dynasty conducted two major systematic observations on this observatory. The first achievement was to formulate the "Yixiang Kaocheng" star catalog with 1744 as the epoch, including 3083 stars; the second achievement On the basis of the first observation, the number of stars was expanded to 3240, which was compiled into the "Yi Xiang Kao Cheng Sequel" star catalog, and 1844 was changed to the epoch.