Giovanni Domenico Cassini (June 8, 1625 - September 14, 1712) was an Italian astronomer and engineer. Cassini was born in Perinaldo, Genoa.


Cassini was an astronomer at the Panzano Observatory, from 1648 to 1669. He was a professor, of astronomy, at the University of Bologna and became, in 1671, director of the Paris Observatory.

Along with Hooke, Cassini is given credit for the discovery of the Great Red Spot (~1665). Cassini was the first to observe four of Saturn's moonss; he also discovered the Cassini Division (1675). Around 1690, Cassini was the first to observe differential rotation within Jupiter's atmosphere.


Cassini was employed, by the Pope, in regards to fortifications, river management, and flooding of the Po.