Born Blois, Loir-et-Cher, France, 18 July 1896
Died Chaponest, Rhône-Alpes, France, 6 November 1967
French spectroscopist Jean Dufay was instrumental in turning the direction of astronomy in his country to spectroscopy and astrophysics and in promoting the modernization of observing equipment during the years between the world wars. Dufay received his bachelor’s degree in 1913 and began advanced work in Paris, but enrolled in the French army in 1915 and was wounded during World War I. He returned to the Faculté des sciences in Paris in 1919, and over the next 9 years, combined research with teaching in the Faculté and several high schools, receiving his Ph.D. in 1928 for work on the light of the night sky with Charles Fabry and Jean Cabannes.
Dufay was appointed to an Aide-astronomeastronomy position at the Observatoire de Lyon in 1929 and became director in 1933. From 1939 to his retirement in 1966, he held simultaneously the directorship at Lyon and that of the newly created Observatoire de Haute-Provence, as well as a professorship in the Faculté des sciences de Lyon. He managed to get both observatories through World War II and German control of France, opposing both the invasion and the resultant racial laws.
Dufay’s main influence was on instrumentation and its use. With Louis Grouiller, he turned work at the Observatoire de Lyon toward spectroscopy, and took an active part in promoting and selecting a site for the Observatoire de Haute-Provence, which remained a major French facility for decades afterward.
Dufay’s own research interests began with spectroscopy of the light of the night sky and broadened in the direction of nebular and nova spectrophotometry, particularly after he reported the Christmas 1934 discovery of cyanogen (CN) bands in the spectrum of Nova Hercules 1934 (DQ Her). Among his students were Joseph-Henri Bigay (who succeeded him as director at Lyon), Marie Bloch, Nguyen Huu Doan, Renée Herman, Agop Terzan, and Tcheng (Cheng) Mao Lin (future director of the Beijing Observatory), a group of unusual diversity in both gender and national origin for its time.