Paris Observatory under construction,with astronomers using a telescope,coloured artwork. This observatory,in Paris,France,was funded by King Louis XIV and built during the period 1667 to 1672. Its first director was the Italian astronomer Giovanni Domenico Cassini (1625-1712),who came to Paris in 1669. Cassini quarrelled with the Observatory's architect,Claude Perrault,arguing for a more practical design. While working at the observatory,Cassini discovered four satellites of Saturn,and a division in Saturn's rings. He also measured the distance to Mars,allowing the Earth-Sun distance to be calculated |