Bachelor of Science, Queen's University, Belfast, 1956. Master of Science, Queen's University, Belfast, 1957. Doctor of Philosophy, University London, 1961.
Assistant lecturer Royal Holloway College, University London, England, 1959-1960, University College London, 1960-1962, lecturer, 1962-1970, senior lecturer, 1970-1999. Assistant director University London Observatory, 1966-1989, director, 1989-1997. Chairman International Astronomical Union Working Group on Adverse Environmental Impacts on Astronomy, 1997-2000.
Visiting fellow University Hertfordshire, since 1999. Chairman International Council of Scientific Unions Working Group on Adverse Environmental Impacts on Astronomy, 1993-1997.
Member Royal Astronomical Society (secretary 1966-1971, vice president 1971-1972, treasurer since 1996), International Astronomical Union (assistant general secretary 1985-1988, general secretary 1988-1991), Institute Physics.
Married Shirley Allen, September 5, 1959. Children: Donal Stewart, Candida Susan.