ABSTRACT
On June 18, 1634, during a lunch gathering with a friend, Mr. Zheng in Haikou, Aleni and Li Jiubiao engaged in a conversation about the movement of stars in heaven.1 As they had done in the past, Li raised a number of questions and his Jesuit master answered accordingly:
After a while, [Li] Qixiang asked: “Lately when reading the Outline of Astronomy (Tianwen lüe) I found that the firmament also has a retrograde movement, but I do not know how many degrees it amounts to in one day.”
