When Brian May was up there on the roof of Buckingham Palace to kick off Her Majesty’s golden jubilee celebrations, it’s a fair bet that most spectators had never heard the National Anthem sound so thrilling. Certainly not even those who understood the personal significance of May being silhouetted against the night sky would have thought: “There goes a poor little eclipse anorak.” But that nerdy chap is what May, guitar god to the masses, sees in himself. Still.

Of course his fascination with astronomy is infinitely more sophisticated than he lets on; it’s just that May doesn’t have the stellar ego that puts it that way. The point is made only on occasions such as this week’s launch of Bang! The Complete History of the Universe, the book May has co-authored with his friend, Sir Patrick Moore, and Chris Lintott.

May’s fascination with astronomy began when he was 7 and saw The Sky at Night. He had just been given his first guitar, and although the latter enthusiasm would come to define him in public, he has never lost his passion for staring at stars. Like music, he has explained, it offers him a way of escaping his Eeyore instincts: for him it is a spiritual as well as an academic pursuit.

Brian Harold May was born in 1947 in Feltham in Middlesex and had the kind of safe middle-class upbringing that would suit an earnest small boy, but which would do nothing to prepare him for being a rock star: “I was not taught how tough life is.” Sensibly, his parents steered him towards astronomy; so he did physics at Imperial College, got a first, and played in bands. It was after he met the art student who would become Freddie Mercury that Queen was formed, and as the band, and Mercury in particular, came to define new levels of performance flamboyance, May remained the reserved one who wrote hits such as We Will Rock You and provided technical brilliance.

Mercury’s death in 1991 followed the death of May’s beloved father, a gifted electronics engineer with whom he had built his guitar (Red Special), and May was treated for depression. He still uses Red Special and regards the guitar as his prime means of expression.

He has three children by his first wife, married the actress Anita Dobson, his long-term partner, in 2000 and lives in Surrey. He seems to lack the ego that demands celebrity recognition, and neither has he conspicuously taken to a rock star’s life — indeed he has been troubled by the invasion his fame has made into his privacy. He could have done without that kind of madness, he has said, and although he doesn’t put his survival down to contemplating the vastness of the Universe, it has obviously provided a useful perspective.