Frenchsolar astronomer and scientific instrument designer. In the 1920s he designed and built a highly sensitive polariscope for studying the Moon and planets in polarized light. Among his findings were that Venus has a high-altitude haze layer, and that Mars has a thin atmosphere and dusty surface. In 1930 he invented the coronagraph for observing the Sun's corona, and various filters for solar observation. In 1935 he made the first cine films of the corona.
Subjects: Astronomy and Astrophysics.