The Components of a Manuscript Scroll
Unrolling Or.8210/S.3326 in the British Library reveals images of clouds and divinatory texts before the star maps. The first portion interprets good and bad omens from cloud shapes and colors; the second divides the sky into consecutive map panels. Their coexistence on one paper scroll shows contemporary connections among sky observation, recognition of stellar positions, and interpretation of signs. The beginning is damaged, and the surviving manuscript has neither a complete original title nor an explicit author’s name.
The star-map portion consists of twelve sectional maps and a circular map of the region around the north celestial pole. Text beside the sectional maps identifies Jupiter stations (ci), months, and related information, while the polar map depicts the arrangement of surrounding stars. A figure drawing a bow appears at the end. As readers unrolled the scroll, they could identify asterisms region by region, examine a particular area, and connect it with adjacent ones. “The whole sky” here means the sky known and observable to Chinese observers; the southern heavens remained limited by the horizon.
How Asterisms Organize the Sky
Small dots represent stars, and fine lines connect them into named asterisms. The arrangement of Shen corresponds to some of the bright stars in what is now called Orion, while the Northern Dipper forms a conspicuous ladle shape in the polar map. The boundaries of the two naming systems differ: an area covered by one modern constellation might contain several asterisms in this scroll. Names drawn from palaces, official positions, fields, and implements give the heavens an order familiar from social and everyday life.
The star dots also use different colors. Researchers connect the red, black, and pale points with the three asterism traditions attributed to Shi Shen, Gan De, and Wu Xian, although the scroll’s coloring is not completely consistent. Color mainly helps distinguish sources of knowledge and asterism affiliations, rather than representing stellar temperatures as in modern maps. The dots are also broadly similar in size, so their size alone cannot establish relative brightness.
Representing a Spherical Sky on a Flat Surface
The sky that surrounds an observer must be rearranged when placed on paper. The twelve panels unfold star regions in different directions into sections, with dots arranged vertically and horizontally in rectangular spaces. A separate circular map brings circumpolar asterisms together for inspection. This combination avoids the crowding that would result from placing the polar region on a single long, narrow map, while giving different areas shapes suited to recognition.
The scroll lacks a complete coordinate grid and does not explicitly draw the celestial equator or ecliptic. Bonnet-Bidaud and colleagues fitted cylindrical-type models to the sectional maps and compared azimuthal-type models with the polar map, finding relatively stable geometrical relationships in the placement of stars. They compared two cylindrical and two azimuthal models, with several yielding similar fits, showing that the same layout is compatible with different mathematical descriptions. The particular calculation and transfer procedures still require examination alongside source copies and traces of copying.
Positions and Observational Accuracy
Testing the atlas first requires identifying which star a dot represents, then comparing its paper position with the star’s calculated ancient position. In their 2009 study, Bonnet-Bidaud and colleagues selected relatively bright, readily identifiable stars and fitted the scales and positions of the maps, obtaining deviations broadly on the order of 1.5 to 4 degrees. These sampled results reveal orderly relationships among stellar positions, while differences in scale and local displacement provide clues for further examination of mapping errors.
Specific local errors are also visible. Canopus is drawn too far north, and some asterisms have problems of shape or naming. Errors could have arisen during observation, compilation, or copying, and the finished map alone makes it difficult to distinguish each source. Text beside the maps concerning the Sun, Moon, and stellar lodges may also preserve older material. The dates of written material, stellar-position data, and the actual copying of the scroll therefore need not coincide exactly.
Who Drew It, and Why Did It Survive?
The 2009 study proposed a date of 649–684 from the taboo-avoiding form of the character min, the normal form of dan, and comparisons of handwriting and astronomical information. Earlier studies had also proposed dates such as the early eighth or tenth century. The phrase “your servant Chunfeng says” in the cloud-divination text points toward the Tang astronomer Li Chunfeng. Researchers accordingly discuss links with Li and associated source texts, while the identity of the surviving manuscript’s actual copyist or drafter remains to be established.
There is still no complete record of how the scroll reached Dunhuang or who used it. The association of maps and divinatory texts suggests possible use in learning or applying star identification and omen interpretation. It was later preserved in the Library Cave at the Mogao Caves. The cave was rediscovered in 1900; Stein acquired this scroll from it in 1907, and it subsequently entered a British collection. Paper preserved knowledge that had circulated through observation and teaching in a form that can be checked point by point. Research today reconnects its stellar dots, texts, and traces of copying.