Stars from the world of showbusiness and science have paid tribute to Sir Patrick Moore who died on Sunday.
Queen guitarist Brian May said the monocled stargazer was the "father of astronomy" in Britain.
Nobel Prize winner Sir Paul Nurse said he was one of the great science communicators of our time.
Sir Patrick, aged 89, "passed away peacefully " at his home in Selsey, West Sussex, friends and colleagues said in a statement.
He presented the BBC programme The Sky At Night for more than 50 years, making him the longest-running host of the same television show.
He wrote dozens of books on astronomy and his research was used by the US and the Russians in their space programmes.
Sir Paul Nurse said his own decision to become a scientist was influenced by Sir Patrick. He described how as a child he attended one of his astronomy talks.
"I literally sat at his feet, listening to every word, and there were a lot of them," he told BBC News. "It was a wonderful experience for me."
He also told of the touching moment when Sir Patrick was elected an honorary fellow of the Royal Society - with tears streaming down his face the astronomer said he was completely overwhelmed that the most famous science academy in the world would recognise him, "just an amateur".
Astronomer Royal Sir Martin Rees said that despite being an amateur scientist, Sir Patrick was a total professional in his work.
"He did his homework; he absorbed new ideas quickly. To a TV audience, he was a 'character' - indeed in the earlier days of science broadcasting the demeanour of a mad professor seemed a prerequisite for media success.
"But in his case, this image overlay a lifetime commitment, a workaholic mission to explain, and an enthusiasm to promote his subject in whatever ways he could."
Queen guitarist Brian May, who published a book on astronomy written with Sir Patrick, described him as a "dear friend and a kind of father figure to me". He said Britain had lost a priceless treasure that could not be replaced.
"We all learned astronomy from Patrick Moore, we learned that kind of thirst and joy for knowledge that he had and shared with everybody, the whole of Britain owes its astronomy to Patrick.
"He lived and breathed his subject, and he shared it with everyone, he absolutely lived to share his knowledge, his wealth and his time. The most generous man I've ever met I would say."
Described by one of his close friends as "fearlessly eccentric", Sir Patrick was notable for his habit of wearing a monocle on screen and his idiosyncratic style.
He presented the first edition of The Sky at Night on 24 April 1957. He last appeared in an episode broadcast last Monday.
A statement issued on Sunday by his friends and staff said: "After a short spell in hospital last week, it was determined that no further treatment would benefit him, and it was his wish to spend his last days in his own home, Farthings, where he today passed on, in the company of close friends and carers and his cat Ptolemy.
"Over the past few years, Patrick, an inspiration to generations of astronomers, fought his way back from many serious spells of illness and continued to work and write at a great rate, but this time his body was too weak to overcome the infection which set in a few weeks ago.
"He was able to perform on his world record-holding TV programme The Sky at Night right up until the most recent episode.
"His executors and close friends plan to fulfil his wishes for a quiet ceremony of interment, but a farewell event is planned for what would have been Patrick's 90th birthday in March 2013."
Patrick Alfred Caldwell-Moore was born at Pinner, Middlesex, on 4 March 1923.
Heart problems meant he spent much of his childhood being educated at home and he became an avid reader. His mother gave him a copy of GF Chambers' book, The Story of the Solar System, and this sparked his lifelong passion for astronomy.
When war came he turned down a place at Cambridge and lied about his age to join the RAF, serving as a navigator with Bomber Command and rising to the rank of Flight Lieutenant.
But the war brought him a personal tragedy after his fiancee, Lorna, was killed when an ambulance she was driving was hit by a bomb. He never married.
Sir Patrick, who received a knighthood in 2001, won a Bafta for services to television and was a honorary fellow of the Royal Society. He had a pacemaker fitted in 2006.
His other TV credits include the role of Gamesmaster in the 1990s computer games show of the same name.
BBC science correspondent Pallab Ghosh said Sir Patrick's appearance sometimes aroused as much comment as his astronomy: "He was 6ft 3in, and was once described as having an air of donnish dishevelment, with his raised eyebrow, scarcely-brushed hair and poorly-fitting suits.
"His enthusiasm was unstoppable, and on occasions he would talk at 300 words a minute."
Television presenter and physicist Prof Brian Cox posted a message on Twitter saying: "Very sad news about Sir Patrick. Helped inspire my love of astronomy. I will miss him!"
The acting director general of the BBC, Tim Davie, said his achievements at the corporation "were unmatched", adding that Sir Patrick will be missed by his "countless fans".
UKIP leader Nigel Farage said: "Since I first met Sir Patrick when he dominated a UKIP stage in 1999, he has been a friend and an inspiration - not only to us in UKIP, but across the country and around the world.
"We have seen the passing of a true great, and a true Englishman."
And Dr Marek Kakula, public astronomer at the Royal Observatory in Greenwich, described him as a "very charming and hospitable man".
"When you came to his home he would always make sure you had enough to eat and drink. He was full of really entertaining and amusing stories.
"There are many many professional astronomers like me who can actually date their interest in astronomy to watching Patrick on TV, so his impact on the world of professional astronomy as well as amateur is hard to overstate."
Chat show host Jonathan Ross tweeted that Sir Patrick was not just a science communicator but an accomplished musician as well: "RIP Sir Patrick Moore. A whiz with a telescope AND on the xylophone!"