Sir Patrick Moore, who has died aged 89, was the most famous face of astronomy and space travel on television. A genuine eccentric who never took himself too seriously, Moore played up to his image as a "mad professor", and wrote more than 100 books – most of them about astronomy for a popular audience.
Meanwhile, his monthly Sky at Night programme – launched on BBC Television in April 1957 – attracted millions of viewers.
On television Moore became celebrated for the thunderous fervour with which he would utter the words: "We just don't know!" to emphasise that our comprehension of the universe is incomplete.
Regular viewers of The Sky at Night – where Moore's extended tenure made him the world's longest-running presenter of a single television show – agreed that the secret of its success lay not only in his tremendous learnedness but also in his gusto and humour.
On one occasion, for example, he appeared dressed in a spacesuit and a fishbowl helmet, pretending to be a Martian.
He was equally famous for the bluntness of his remarks. Commenting further on the probable ubiquity of alien life in space, he said: "Somewhere in the universe there could be a complete carbon copy of Anthony Wedgwood Benn (a very left wing British politician) – although I sincerely hope not."
Patrick Alfred Caldwell-Moore was born at Pinner, Middlesex, on March 4, 1923, the son of Captain Charles Caldwell-Moore. Later the family moved to Sussex, where Patrick lived for the rest of his life. He was educated at home owing to ill health, and wrote his first scientific paper at the age of 13.
At the end of 1941 he joined the RAF to train for aircrew duties. He was commissioned in June 1944 but, due to epilepsy, was declared medically unfit for further flying duties. He spent some time in the RAF's training branch before leaving the Service in 1947.
When asked why he never married, Moore would say his fiancée had been killed in the war – she was a victim of Nazi Germany's Blitz on London – and he would not settle for second best. "I would have liked a wife and family, but it was not to be," he said.
From 1952 he had made his living as a freelance writer. The Sky at Night started almost by accident. One day in 1957 the BBC broadcast a somewhat sensationalist programme about flying saucers. Producers wanted a counterview by a "thoroughly reactionary and sceptical astronomer who knew some science and could talk". This turned out to be Moore. He little guessed that he was starting a series that would last for half a century.
"We had many problems," he once observed. "At that time astronomy was regarded as an eccentric study practised by old men with long white beards. The space age had not started."
But with Cold War competition driving on the superpowers, the world's attention was soon directed upwards. Moore became an essential guide to heavens above.
His popularity, however, was not achieved at the expense of scholarship. His books were as meticulous as those of the Royal Society Fellows who attracted only a few hundred readers. His coffee-table masterpiece The Atlas of the Universe (1970, revised 2007) was a feast of accurate knowledge about comets, asteroids, stars and galaxies.
Yet there were many other sides to Moore besides astronomy. He was a connoisseur of music, and sometimes played a xylophone on television.
He always loved our planet's satellite – the moon. "I would love to go there," he said, "but I'm too old." Instead, through his powerful 15in reflecting telescope he charted its craters so accurately that the Russians used his maps to plan their unmanned lunar probes.
In 2002 Moore was appointed honorary vice-president of the Society for the History of Astronomy. He also won a Bafta for his services to television, a medium on which he became probably the first man to swallow a fly live on air. His producer recalled the look of glazed horror as the insect vanished into Moore's mouth in mid-flow, the presenter's words finally failing in a strangled gulp. "Yes, dear," his mother sympathised later, "it was nasty for you, but so much worse for the fly."
Patrick Moore continued to publish books to the end of his life. He was appointed OBE in 1968, CBE in 1988 and knighted in 2001.