French-Italian astronomer who measured the period of rotation of Jupiter and issued a table of the motions of Jupiter's moons. He also discovered the moons of Saturn Iapetus (1671), Rhea (1672), Dione (1684), and Tethys (1684). Cassini discovered that Saturn's rings were divided by a dark gap. He also determined the parallax of Mars, which allowed the calculation of the distance to Mars and the Earth -Sun distance.

Additional biographies: MacTutor (St. Andrews), Firenze, Bonn