At the beginning of the 1900s, around 7000 excellent conserved documents were fof und in a monastery, along the Silk Road near the oasis city of Dunhuang (Gansu, China). The monastery was active from around 360 AD until the end of the Mongol Empire (1368 AD). Most othe Dunhuang documents are religious texts on Buddhism but a few of them concern medicine, divination and astronomy. Among them was a scroll of thin paper, now known as the Dunhuang star chart, that was collected among other manuscripts and sent to the British Museum.
The scientific analysis was initiated in 2004 at the British Library. The beginning of the scroll is missing, and the document is divided in two different parts. The first section is an uranomancy text containing drawings of clouds of different shapes. It is followed by the detailed star atlas consisting of 12 rectangular panels along the celestial equator ending with a circular map of the polar region. A total of more than 1300 stars is distributed in 257 different Chinese constellations, according to the very long Chinese astronomical tradition described in earlier star catalogues.
A very interesting film has been released by CNRS images on SD, where archaeologists give insight into the historical meaning of the star chart and how advanced it was. The most important message to me is that even if Buddhist monks were running the place the map was possibly done by Taoists, who had a strong interest in natural sciences. Meaning that ideally no matter what you believed in, the observation of the sky and its representation were non-partisan. This is an important part of my practice as well. When we are with the stars and the fireflies, we are one with the environment, we are closer to being one species among others around us, immersed in darkness.
You can watch the film, by clicking on the links below:
https://images.cnrs.fr/en/video/2078
https://images.cnrs.fr/video/2078
And again, I am fascinated both by the effort of the mathematicians back in Dunhuang and by the transdisciplinary work being done today among the various disciplines involved, to create meaning, based on a common will to understand, in this case, the representation of the night sky and its constellations.
The dating of the document proved to be a piece of real detective work. As the beginning of the scroll was missing, the title and the name of the author were not visible. However, in the first part of the scroll devoted to clouds divination, a clear mention is made of a comment by Li Chunfeng (+602-670), an outstanding Chinese mathematician and astronomer who could possibly be the author. The final proof came from a particularity of the Chinese tradition and writing, called the taboos characters. During the reign of any emperor, characters that made up the emperor's personal name were not allowed to be used in their standard form. The characters were changed slightly, usually by omitting or adding a stroke. This is known as the taboo form of the character. From this, it was possible to deduce that the document was produced after the reign of the Taizong emperor (+649) and before the Ruizong emperor (+684).
The study has also provided an evaluation of the accuracy of the atlas. The positions of the brightest stars have been measured using a high resolution digitized copy of the document and compared to the predicted positions using various projection methods.
