Liú Hóng 劉洪
Style name Yuánzhuō 元卓. Late Eastern-Hàn astronomer-mathematician. Native of Méngyīn 蒙陰 in Tàishān commandery 泰山郡 (modern Shāndōng), descended from the Hàn imperial Liú clan via Lǔwáng 魯王. Conventional lifedates c. 130 – c. 210 CE (the precise dates are not securely attested; the dates given are the consensus of the standard reference works including the HòuHàn shū and modern reconstructions by Sivin, Cullen, and the Zhōngguó tiānwénxué shǐ). CBDB does not have a securely-identified entry for the Eastern-Hàn astronomer (the entries for 劉洪 in CBDB are MíngQīng homonyms).
Liú Hóng is the designer of the Qiánxiàng lì 乾象曆, the calendar promulgated as the official calendar of the state of Wú 吳 in 223 CE — adopted there because the official Wèi 魏 court had retained the older Sìfēn lì (cf. KR3fc052). The Qiánxiàng (cf. KR3fc053) is the first Chinese calendar to incorporate a non-circular model of lunar motion (the huíchà 回差 or “return-difference” reflecting the variation in lunar speed between perigee and apogee) and a non-zero value for the inclination of the lunar orbit. Both innovations are foundational to subsequent Chinese calendrical astronomy.
Liú Hóng’s appointment as Grand Astrologer (Tàishǐlìng 太史令) under Hàn Língdì 漢靈帝 placed him at the center of late-Hàn astronomical work. His mathematical biography is preserved in 阮元 Ruǎn Yuán’s Chóurén zhuàn 疇人傳 (compiled with 李銳 Lǐ Ruì’s collaboration), which provides the principal Qīng-period historiographical account.