 In 1956, he moved to the Royal Greenwich Observatory at Herstmonceux Castle where he spent the greater part of his career, eventually progressing to the grade of Deputy Chief Scientific Officer.In 1967, he became a Visiting Reader (and later Visiting Professor) in Astronomy at Sussex University.Upon his retirement from the Royal Greenwich Observatory in 1990, he moved to a Chair at the Nordic Institute for Theoretical Physics (NORDITA) in Copenhagen.