fl. fourth century B.C.

Chinese astronomer known for his star catalogue and his studies of sunspots. Along with Shih Shen and Wu Xien (Wu Hsien), Gan De was one of three scholars who independently developed a star catalogue that would, centuries later, be included in a single star map. As for his studies of sunspots, which he described as eclipses that began at the center of the Sun and moved outward, Gan De's work in this regard was about 12 centuries ahead of the West: only in A.D. 807 did a European scientist mention sunspots.