Ferdinand Verbiest and the ‘Muslim astronomical system’ of Wu Mingxuan, 1669

Résumé En

In early 1669, the Jesuit missionary astronomer Ferdinand Verbiest (1623-1688, Nan Huairen 南懷仁 in Chinese) was ordered by the Kangxi emperor (r. 1662-1722) to take part in a test of his abilities to make accurate astronomical predictions, principally those needed to construct a lunisolar calendar of the type used by all literate members of the population of Imperial China, lay or official, for planning their daily activities. He was to do this in competition with the Muslim astronomer Wu Mingxuan 吳明烜. In his account of that competition, Verbiest states repeatedly that Wu based his predictions on the ‘Muslim [astronomical] system’ (Hui hui li 回回曆). This essay is an initial investigation of the methods used by Wu Mingxuan to make astronomical calculations, with the aim of finding the extent to which his results really were based on the system to which Verbiest refers. This investigation indicates that Verbiest’s characterisation of Wu Mingxuan’s methods is incorrect. Wu Mingxuan was in fact using a version of the Ming dynasty’s Great Concordance system Da tong li 大統曆, that had been restored to use by the Astronomical Bureau (Qin tian jian 欽天監) after Jesuit astronomers and their Chinese colleagues were deprived of their offices in 1665 as a result of the accusations made by Yang Guangxian 楊光先. The reasons why Verbiest nevertheless described Wu’s methods as ‘Muslim’ are best understood in the context of the Jesuits’ struggle to re-establish themselves as astronomical experts at the Qing court.