Plaque de la rue Cassini in Paris - Street Plaque in Paris - Rue du...

Plaque de la rue Cassini in Paris - Street Plaque in Paris - Rue du 14eme arrondissement de Paris, in tribute to the Italian astronomer Jean - Dominique Cassini (1625 - 1712), naturalise French in 1673. Attrained to France by Colbert in 1669, he became the first director of the Paris Observatory in 1671, at the request of Louis XIV. In 1665, he discovered Jupiter's Grande Tache Rouge and determined the rotation speeds of Venus, Mars and Jupiter. From 1671 he discovered 4 satellites around Saturn, as well as a separation in the rings, which today bears his name (division of Cassini). In 1673, he made the first precise measurement of the distance from Earth to Sun, thanks to a transit of Venus. Rue Cassini, street sign. Astronomer Jean - Dominique Cassini, was the first director of Paris observatory