Bernard Lyot (1897-1952), well versed in optical instruments, managed to build this instrument that enables one to see the solar corona even without a total solar eclipse, and even though it is a million times less bright than the solar disc. This invention, equipping many ground- and space-based telescopes, has evolved so that it has also enabled us to see the planets around neighbouring stars, by efficiently cutting off the stellar light.

caption : The coronagraph at the equatorial of the Carte du Ciel - credits : Observatoire de Paris