Frenchastronomer and geodesist, son of G. D. Cassini; also known as Giacomo Cassini. His accurate determination of the length of an arc of a meridian passing through France, later extended by his son César François, showed that the Earth is an oblate spheroid (i.e. flattened at the poles). He compiled the first tables of the motion of Saturn's satellites and in 1738 made one of the first definite determinations of a star's proper motion, that of Arcturus.
Subjects: Astronomy and Astrophysics.