Astronomer. He was a professor of astronomy at the University of Bologna, and later became director of Paris Observatory. He discovered four of Saturn's moons, Iapetus, Rhea, Dione and Tethys. He also discovered the Cassini division in Saturn's rings, named after him. He is was the discoverer of Jupiter's Great Red Spot. In 1690, he was the first to observe the differential rotation of Jupiter's atmosphere. In his honor was dedicated the space mission that in 2004, started exploration of Saturnian system.
Bio by: Ruggero