Related knowledge of Dunhuang star map

Star map is an image record of star observation and an important tool for identifying stars and indicating positions in astronomy. The star map is different from the traditional geographical atlas or celestial photos, that is to say, it accurately describes or draws the persistent features in the night sky, such as stars, constellations composed of stars, Milky Way, nebulae, star clusters and other extragalactic galaxies, which are also called "star maps".

Only China has preserved the maps before14th century. During the Three Kingdoms period, Chen Zhuo of the State of Wu drew the stars observed by Gander, Shen Shi and Wuxian in different ways on the same map around 270 AD, with a total of 1 464 stars. Although this star map has been lost, it can be seen from the silk book map in Dunhuang. The astronomical map of Suzhou stone carvings was drawn according to the observation results in Yuanfeng period of Northern Song Dynasty (A.D. 1078 ~ 1085). The star map contained in the "New Instrument and Image Method" was drawn on 1088, but the observation results are the same as those of Suzhou stone carving astronomical map.

The western classical star map originated from ancient Greece and Rome, and it is mainly an artistic Greek star map, which only shows the schematic diagram of constellations and does not show the stars themselves. The early famous classical star map was drawn by the medieval monk Geruvigus around AD 1000. It was collected by Harry and his son and is now in the British Museum. Geruvigus's star map is simple in style and slightly rough compared with later classical star maps, but it has a great influence on later star map painters, and its shadow can be seen in many star maps.

1569, G.Mercator, a Dutch cartographer, founded the Mercator projection method, which is one of the most influential map projection methods and is widely used to compile nautical charts and aeronautical charts.

After the invention of the telescope, the earlier star maps in Europe were 54 in the Astronomical Atlas compiled by Jahannes Hewelius (1657 ~ 1690). Jahannes Hewelius's star map was revised by frans Ted and reprinted in 1725, with a total of 2,866 stars. The Bonn star map published by 1863 is a famous early star map.