David Stanley Evans

David Stanley Evans (28 January 1916 – 14 November 2004) was a British astronomer, noted for his use of lunar occultations to measure stellar angular diameters during the 1950s.

Evans was born in Cardiff, Wales on 28 January 1916. He was first educated at the Cardiff High School for Boys. He obtained a First Class in the Mathematics Tripos Part II in 1936 and a Distinction in Part III in 1937 from King's College, Cambridge and became a Ph.D. student at Cambridge Observatory in 1937, where he was a student of Sir Arthur Eddington. His Ph.D. degree was awarded in 1941 for a dissertation on “The Formation of the Balmer Series of Hydrogen in Stellar Atmospheres.” Being a conscientious objector to World War II he spent the war years at Oxford with physicist Kurt Mendelssohn where they worked on medical problems relating to the war effort. Over this period he was scientific editor of Discovery and editor of The Observatory.

Evans left England in 1946 to work at the Radcliffe Observatory, Pretoria, South Africa when positional determinations and photometry were the main interests of the astronomical world, but when he left some twenty years later, the South African observatories had become active in astrophysics. Together with Harold Knox-Shaw he aluminised and installed the mirrors in the 74-inch (1.9 m) telescope. He determined the angular diameter of Antares and also wrongly came to the conclusion that Arcturus was elliptical in shape. This was later found to be an observational artifact, but the feasibility of measuring stellar diameters using lunar occultations, was soundly established. At this time Evans had become chief assistant at the Royal Observatory in Cape Town, South Africa. He designed and oversaw construction of a Newtonian spectrograph for the 74-inch (1.9 m) Radcliffe Telescope with which he measured the first southern galaxy redshifts.

...
Wikipedia