Chinese records of comets dated back to a lon,g tim,e ago . During the Spring and Autumn Period, some 2,200 years ago, Chinese documents already had records of comets, among which the most verifiable one is the record of a comet, which appeared in 613 BC, iri Sprin,g an,d Autumn, Annals . It iS recog-nized as the earliest mention of Halley's Comet in the world, 670 years earlier than the Western Europe, where the earliest record of Halley's Comet was in AD 66.
国古代关于彗星的纪事很早。早在2200多年前春秋时期的古文献中已有关于彗星的记录。最可靠的是《春秋》对出现于公元前613年的彗星记录。这是世界上关于哈雷彗星的最早记录。西欧对哈雷彗星的最早记载是公元66年，这比中国最早的记载晚了670余年。
Since Halley's Comet visits the earth once every 76 years, it came back to the earth 29 times during a period of 2,149 years from 240 BC ( the 7th year of the reign of the First Emper-or of Qin) to 1910 ( the 2nd year of the reign of Emperor Xuantong of Qing). Each of these vis-its was clearly recorded by Chinese scholars.J. R. Hind, a British astronomer, once usedthese continuous data to calculate the orbit of Halley's Comet, and discovered that the angle of the orbit showed a narrowing trend. In the Han Dynasty, it was 170 degrees, but it nar-rowed down t0 161 degrees in the mid-9th century.
