Huygens, Christiaan (1629–1693)
- Dutch astronomer who lived mainly in Paris. He was a very able builder of telescopes, and contributed much to the theory of optics. He also made some of the first telescopic observations of Mars, discovered Titan, the largest satellite of Saturn, and solved the mystery of Saturn’s strange appearance. Galileo’s telescope had shown that Saturn has an odd and variable triform appearance, but Huygens was able to show that this is due to the presence of its ring system.