John Donovan Strong was a professor of Physics and Astronomy from 1967 to 1975 and served as the head of the laboratory of astrophysics and physical meteorology. Strong, one of the world’s foremost optical scientists, was known for being the first to detect water vapor in the atmosphere of Venus and for developing a number of innovations in optical devices, ranging from improved telescope mirrors to anti-reflective coatings for optical elements and diffraction gratings. Born in Lawrence, Kansas in 1905, Strong received degrees from the University of Kansas (BA 1926) and the University of Michigan (M.S., 1928, Ph.D., 1930). After twelve years at Caltech and wartime research at Harvard on infrared systems, Strong became professor and director of the Astrophysics and Physical Meteorology Labo