Under Sweet's stewardship, the Department of Astronomy grew from 3 to 17 permanent staff.
Sweet undertook the building of a new University Observatory located at Acre Road, Glasgow which opened in 1967.
Sweet was educated at Kingsbury County Grammar School and Wrangler 1942 on a Major Open Scholarship in Maths at Sidney Sussex College, Cambridge.
He worked as a Junior Scientific Officer at the Ministry of Aircraft Production from 1942 until the end of the World War II.
He then moved to become Assistant Director of the University of London Observatory from 1952 until his appointment to the Regius Chair in Glasgow in 1959.