Bengt Georg Daniel Stromgren (1908-1987), Danish astrophysicist. Stromgren studied the chemical composition of the stars, pioneering photometric techniques. He studied at the University of Copenhagen, and in 1929 was awarded his doctorate aged 21. He spent the war years in German-occupied Denmark, then left for the USA in 1951. He was director of the Yerkes Observatory and the McDonald Observatory. From 1957 he was professor of theoretical astrophysics at the Institute for Advanced Study in Princeton. He was awarded the Gold Medal of the Royal Astronomical Society in 1962. Photographed in 1957, at the Yerkes Observatory, Wisconsin, USA.