Overview
Key data
| Item | Detail |
|---|---|
| Period | Yuan and Ming |
| Office | Islamic Astronomical Bureau |
| Origin | Islamic calendar |
Arrival and office
The Huihui calendar came with the westward peoples who entered under the Yuan, and the Yuan set up a bureau to keep it. The Ming carried on the arrangement, keeping a Huihui section in the Imperial Observatory alongside the Datong calendar.
The Islamic calendar is purely lunar: months begin at the new moon, twelve months make a year of about 354 days, and intercalary days reconcile it with the solar year. Its year head has nothing to do with the solar terms and its system differs from the Chinese.
Documents
The Ming Huihui lifa and related translations preserve the Arabic astronomical data and methods then brought in, a first-hand source for the study of Sino-Arab exchange.
Two systems ran side by side for centuries: Chinese astronomy was no closed world.
Compiled and arranged by Chujia Kuang.