Historic 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. Records exist at least as far back as 613 BC, and records may have been kept for many centuries before this. There are continuous records all the way through to the nineteenth century, using substantially consistent methods throughout. Chinese data accuracy is unsurpassed in the ancient world and was not overtaken by Western accuracy until the fifteenth century, in some respects, not until the twentieth century.

Comets were observed in great detail because of their astrological significance. However, these observations are now of great use to modern astronomers. Their accuracy is sufficient to allow the calculation of orbital elements, and modern astronomers have done this for many comets. Most notably, ancient orbits of Halley's Comet have been determined using Chinese records, a feat not possible solely from modern data due to a close approach of the comet to Earth in the ninth century. Such close approaches cause comet orbits to change abruptly, and ancient changes of this sort cannot be accurately modelled from the comet's present-day orbital data.

Ancient Chinese records of comet observations are the most extensive historical records in existence. They are far more complete than European observations. The earliest confirmed Chinese comet observation is from 613 BC, but there is also a possible sighting of Halley's Comet in 1059 BC. However, this may not be an actual sighting, but the result of later back calculation.

Early records call comets beixing (or boxing: 孛星, "bushy star" or "sparkling star" according to Yeomans et al.). Later on, a distinction is made between beixing and huixing (彗星, "broom star"), that is, comets without, and with a tail respectively. The broomstick here is a metaphor for the tail and the broomhead the head of the comet. Chinese astronomers were the first to observe that comet tails point away from the sun. They knew this by at least 635 AD, many centuries before the phenomenon was observed in the West. Other descriptive Chinese names for comet include saoxing (掃星, "sweeping star"), tianchan (天攙, "heavenly intermingler"), fengxing (篷星, "sailing star"), changxing (長星, "long star"), and zhuxing (燭星, "candle-flame star").

...
Wikipedia