The Dunhuang chinese sky: a comprehensive study of the oldest known star atlas

TL;DR

This paper analyzes the oldest complete Chinese star atlas from the early Tang dynasty, revealing its detailed stellar content, precise mathematical construction, and historical significance in the context of medieval celestial cartography.

Contribution

It provides a comprehensive analysis of the Dunhuang star atlas, including its content, accuracy, historical dating, and comparison with other ancient sky maps, highlighting its uniqueness and significance.

Findings

Contains 1339 stars and 257 asterisms

Uses precise mathematical projections with 1.5 to 4 degrees accuracy

Dates to 649-684 CE, early Tang dynasty

Abstract

This paper presents an analysis of the star atlas included in the medieval Chinese manuscript (Or.8210/S.3326), discovered in 1907 by the archaeologist Aurel Stein at the Silk Road town of Dunhuang and now held in the British Library. Although partially studied by a few Chinese scholars, it has never been fully displayed and discussed in the Western world. This set of sky maps (12 hour angle maps in quasi-cylindrical projection and a circumpolar map in azimuthal projection), displaying the full sky visible from the Northern hemisphere, is up to now the oldest complete preserved star atlas from any civilisation. It is also the first known pictorial representation of the quasi-totality of the Chinese constellations. This paper describes the history of the physical object - a roll of thin paper drawn with ink. We analyse the stellar content of each map (1339 stars, 257 asterisms) and the texts associated with the maps. We establish the precision with which the maps are drawn (1.5 to 4 degrees for the brightest stars) and examine the type of projections used. We conclude that precise mathematical methods were used to produce the atlas. We also discuss the dating of the manuscript and its possible author and confirm the dates 649-684 (early Tang dynasty) as most probable based on available evidence. This is at variance with a prior estimate around +940. Finally we present a brief comparison with later sky maps, both in China and in Europe.