Giovanni Cassini

Giovanni[a] Domenico Cassini (8 June 1625 – 14 September 1712) was an Italian mathematician, astronomer, astrologer and engineer.

https://en.wikipedia.org/wiki/Giovanni_Domenico_Cassini

Wikipedia Biographical Summary:

"...Giovanni Domenico Cassini (June 8, 1625 – September 14, 1712) was an Italian/French mathematician, astronomer, engineer, and astrologer. Cassini, also known as Giandomenico Cassini or Jean-Dominique Cassini, was born in Perinaldo, near Sanremo, at that time in the Republic of Genova..."

"...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..."

"...Cassini was the first to observe four of Saturn's moons..."

"...In addition he discovered the Cassini Division in the rings of Saturn (1675). He shares with Robert Hooke credit for the discovery of the Great Red Spot on Jupiter (ca. 1665). Around 1690, Cassini was the first to observe differential rotation within Jupiter's atmosphere..."

"...In 1672 he sent his colleague Jean Richer to Cayenne, French Guiana, while he himself stayed in Paris. The two made simultaneous observations of Mars and, by computing the parallax, determined its distance from Earth. This allowed for the first time an estimation of the dimensions of the solar system: since the relative ratios of various sun-planet distances were already known from geometry, only a single absolute interplanetary distance was needed to calculate all of the distances..."

"...During this time, Cassini's method of determining longitude was used to measure the size of France accurately for the first time. The country turned out to be considerably smaller than expected, and the king quipped that Cassini had taken more of his kingdom from him than he had won in all his wars. Cassini went blind in 1711..."

SOURCE: Wikipedia contributors, 'Giovanni Domenico Cassini', Wikipedia, The Free Encyclopedia, 15 August 2011, 17:55 UTC, <http://en.wikipedia.org/w/index.php?title=Giovanni_Domenico_Cassini...> [accessed 24 September 2011]