Gan De

For the Chinese Jupiter probe previously known as Gan De, see Tianwen-4.
Gan De
Chinese甘德
Transcriptions
Standard Mandarin
Hanyu PinyinGān Dé
Wade–GilesKan1 Te2
IPA[kán tɤ̌]

Gan De (Chinese: 甘德; fl. 4th century BC), also known as the Lord Gan (Gan Gong), was an ancient Chinese astronomer and astrologer born in the State of Qi.[1] Along with Shi Shen, he is believed to be the first in history known by name to compile a star catalogue, preceded by the anonymous authors of the early Babylonian star catalogues and followed by the Greek Hipparchus who is the first known in the Western tradition of Hellenistic astronomy to have compiled a star catalogue. He also made observations of the planets, particularly Jupiter. His writings are lost, but some of his works' titles and fragments quoted from them are known from later texts.

Gan De may have been the first to describe one of the Galilean moons of Jupiter, usually invisible without the aid of telescopes. In the 20th century, a fragment of Gan's work, in a later compilation of astronomical texts, was identified by Xi Zezong as describing a naked-eye observation of either of the two largest and brightest moons, Ganymede or Callisto in summer 365 BC.

  1. ^ Shiji 27 stated that he was from the State of Qi; however, according to a 4th-century BCE testimony by Xu Guang, he was actually from the State of Lu. Further citation from another work dated to the 5th century by Ruan Xiaoxu gives an account indicating that he was from the State of Chu.