Historical comet observations in China

Chinese records of comets are the most extensive and accurate in existence from the ancient and medieval periods, and stretch back across three millennia.

Later on, a distinction is made between beixing and huixing (彗星, "broom star"), that is, comets without, and with a tail respectively.

[8] The Chinese records are not only the most extensive from ancient times, they are also the most accurate, often to within half a degree of right ascension.

Western measurements did not overtake them for accuracy until the fifteenth century: in 1456 AD Paolo Toscanelli tracked the progress of Halley's Comet to within a fraction of a degree.

However, the dates are recorded, and the time can be estimated to within one or two hours by considering when the Chinese observers would have had good viewing conditions.

[8] Chinese records of comet brightness are superior to Western observations to an even later date.

The West did not overtake Chinese astronomers in this respect until the twentieth century, at least in the matter of diligent recording of brightnesses.

It may be associated with a similar astronomical text from the same tomb, which details planetary motions for the seventy years ending 177 BC.

[12] Wenxian Tongkao, a thirteenth century compilation by Ma Duanlin, includes a list of comets up to 1222 AD.

[13] The Chinese records have some importance to modern science because they allow astronomers to deduce the past orbits and brightnesses of comets.

Astronomer John Russell Hind observed that past apparitions of Halley back to 12 BC in most cases could be matched to these Chinese records.

[19] Studies of historical changes in brightness of Halley's Comet have also been carried out using ancient Chinese data.

[20] Under the theory of Wu Xing, comets were thought to signify an imbalance of yin and yang.

For instance, the breakup of a comet on 25 January 35 AD was interpreted as portending the destruction of Gongsun Shu by Wu Han, general to emperor Guangwu.