Cassini family

A French family of astronomers, geodesists and cartographers of Italian origin whose members directed the Paris Observatory across successive generations for more than a century. Giovanni Domenico Cassini (1625–1712), known as Cassini I, an astronomer of Italian origin who was naturalized as a French citizen, was the first director of the Paris Observatory and the founder of the line. An exceptional observer, he discovered several of Saturn's satellites and the division in Saturn's rings that bears his name. His son Jacques Cassini (1677–1756), known as Cassini II, succeeded him as head of the Observatory and devoted himself chiefly to measuring the shape of the Earth, arguing, against Newton, that the Earth was elongated at the poles. César-François Cassini de Thury (1714–1784), known as Cassini III, Jacques's son, revised his father's conclusions on the Earth's shape and undertook the production of the first general map of France based on systematic triangulation, a work that remains his principal scientific legacy. Jean-Dominique, comte de Cassini (1748–1845), known as Cassini IV, César-François's son, completed the publication of this map and took part in surveying operations linking the Paris and Greenwich meridians, before withdrawing from scientific work after the Revolution. Alexandre-Henri (1781–1832), vicomte de Cassini, the latter's son, abandoned the family tradition to devote himself to the judiciary and botany, bringing the line of Cassini astronomers to an end.