Gan De Chinese astronomer Date of Birth: . Country: China

1. Gan De: The Ancient Chinese Astronomer
2. Collaboration and Star Catalog Creation
3. Observation and Discovery of Jupiter

Gan De: The Ancient Chinese Astronomer

Gan De, known as Gan Gong, was a renowned Chinese astronomer and astrologer who lived approximately during the 4th century BCE. He hailed from the state of Qi.

Collaboration and Star Catalog Creation

Together with Shi Shen, Gan De authored the oldest known star catalog in human history. This groundbreaking work cataloged thousands of stars, marking a significant milestone in astronomical observation.

Observation and Discovery of Jupiter

Gan De is credited with the first observation of Jupiter. He described the planet as brilliantly radiant, noting its distinct appearance. Notably, he recorded witnessing one of Jupiter's moons (either Ganymede or Callisto) with his unaided eye in 364 BCE. This observation predated Galileo Galilei's celebrated discovery of the same moon by over two thousand years. While all four of Jupiter's moons are technically visible, they are typically hidden by the planet's intense brightness. Gan De's keen observation stands as a testament to his advanced astronomical abilities.