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Zu Chongzhi
Southern Dynasties mathematician and astronomer who put precession into the Daming calendar and bounded pi between 3.1415926 and 3.1415927
On an observatory terrace at night, a large bronze armillary sphere stands on a stone base while two people stand with their backs turned facing the view; stars are joined into constellation lines overhead, and a sundial and tiered dripping water vessels stand at the right.
Also known as Zi Wenyuan
- Roles
- Scientist
Zu Chongzhi, courtesy name Wenyuan, came from Qiu in Fanyang; his grandfather was a Song master of works, and he studied mathematics from boyhood. In 462 he presented the Daming calendar, the first to take account of precession, which replaced the cycle of seven leap months in nineteen years with one of 144 in 391. The favourite Dai Faxing attacked it and Zu answered point by point, but the calendar was not adopted until 510, under the Liang. According to the treatise on harmonics and calendars in the History of Sui (Suishu), he placed pi between 3.1415926 and 3.1415927 and gave 355/113 as its close ratio and 22/7 as its rough one. He also built a south-pointing carriage and water-powered mills, and wrote the Zhui shu. Under the Southern Qi he was a colonel of the guard, and he died in 500 at seventy-one. The Zhui shu was a set text in the Tang state school of mathematics and was later lost.
Life and times
Dates 429 CE–500 CE