Halley's Comet returns every 76 years, and from the 7th year (300 BC) of the reign of the first Qin Emperor to the 2nd year (1910) of the reign of the last emperor of China, the Qing emperor Xuantong, every appearance was recorded in detail.
哈雷彗星每七十六年回歸一次，中國歷史上，從秦始皇七年到清宣統二年，每一次都有詳細記錄。