He attended Beal Grammar School in Ilford where he wrote astronomy articles for the school magazine. Before entering publishing he was an assistant in the lunar research group at the University of London Observatory, Mill Hill. He now lives in Brentford, Middlesex.
He is editor of the Oxford Dictionary of Astronomy and Norton's Star Atlas, and author of observing guides such as The Monthly Sky Guide and the Collins Stars and Planets Guide (the latter two with charts by Wil Tirion, and both continuously in print for over 25 years). His other books include Star Tales, about the origins and mythology of the constellations, and the children’s book Exploring Stars and Planets, now in its fifth edition. He was a major contributor to the Dorling Kindersley encyclopedia Universe. He is a former editor of the UK quarterly magazine Popular Astronomy.
In 1990 he won an award in The Aventis Prizes for Science Books (in the under-8 children's books category) for The Giant Book of Space. In 2012 he received the Astronomical Society of the Pacific’s Klumpke-Roberts Award for outstanding contributions to the public understanding and appreciation of astronomy.
His early books on the subject of extraterrestrial life and interstellar travel – Worlds Beyond (1975), Messages from the Stars (1978) and Life off Earth (1983) – led him to investigate UFOs. But he rapidly became a sceptic, a position reinforced by his findings about the Rendlesham case. He was one of the first to offer an explanation for the so-called Sirius Mystery involving the supposedly advanced astronomical knowledge of the Dogon people of Mali, west Africa.
He was a space expert for LBC Radio from the 1970s into the 1990s, and was also seen on BBC TV’s Breakfast Time programme in its early years. It was for Breakfast Time that he first investigated the Rendlesham Forest UFO case.
From 1993 to 1995 he was Race Director of the Polytechnic Marathon from Windsor to Chiswick, Britain’s oldest marathon race which traced its origins back to the 1908 Olympic Marathon. In that role, he was involved in a public controversy over the ownership of the Sporting Life marathon trophy, originally awarded to winners of the Polytechnic Marathon, which was claimed in 1994 by the London Marathon. The Polytechnic Marathon was last held in 1996.
 Selected bibliography
- Stars and Planets Guide. Collins (UK). ISBN 978-0-00-725120-9. Princeton University Press (US). ISBN 978-0-691-13556-4.
- Monthly Sky Guide. Cambridge University Press. ISBN 978-0-521-13369-2.
- Gem Stars. Collins. ISBN 978-0-00-717858-2.
- Times Universe. Times Books. ISBN 978-0-00-716930-6.
- Exploring Stars and Planets. Philip’s. ISBN 978-1-84907-144-4.
- Star Tales. Lutterworth. ISBN 978-0-7188-2695-6.
- Oxford Dictionary of Astronomy (ed.). Oxford University Press. ISBN 978-0-19-921493-8.
- Norton’s Star Alas and Reference Handbook (ed.). Dutton. ISBN 978-0-13-145164-3.
- Personal website CV
- Rendlesham Forest UFO investigation pages
- Article on astronomical causes of UFOs
- Star Tales – History and mythology of the constellations
- Astro stamp pages
- Ian Ridpath's page at Amazon Author Central