Jean Dufay

Jean Claude Barthélemy Dufay (July 18, 1896–November 6, 1967) was a French astronomer.
During his career he studied nebulae, interstellar matter, the night sky and cometary physics. In 1925, while working in collaboration with Jean Cabannes, he computed the altitude of the Earth's ozone layer. He was named the honorary director of the Lyon and Haute-Provence observatories.
He became a member of the French Academy of Sciences in 1963.
His undergrad was completed in 1913 and his Ph.D. in 1928 under Charles Fabry. In between he served (and was wounded) in World War I and taught.
He was awarded the Valz Prize by the French Academy of Sciences in 1932 for his work on astronomical photometry. The crater Dufay on the Moon is named after him. 