British astronomer and broadcaster Sir Patrick Moore has died, aged 89, his friends and colleagues have said.
He "passed away peacefully at 12:25 BST this afternoon" at his home in Selsey, West Sussex, they said in a statement.
Sir Patrick presented the BBC programme The Sky At Night for over 50 years, making him the longest-running host of the same television show ever.
He wrote dozens of books on astronomy and his research was used by the US and the Russians in their space programmes.
A statement 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 Mar 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.
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: "Patrick will be mourned by the many to whom he was a caring uncle, and by all who loved the delightful wit and clarity of his writings, or enjoyed his fearlessly eccentric persona in public life.
"Patrick is irreplaceable. There will never be another Patrick Moore. But we were lucky enough to get one."
British space scientist Maggie Aderin-Pocock said she was first inspired to "look at the night sky" through Sir Patrick.
"Through his regular monthly programmes he was telling us what to look for and what was out there and that was a real inspiration.
"Why [The Sky At Night] was so successful is because of his passion. He branched an amazing era, he was broadcasting before we actually went into space and so he saw a change in our understanding of the universe and he took us all the way through that, right up to today."
Professor Brian Cox posted a message on Twitter saying: "Very sad news about Sir Patrick. Helped inspire my love of astronomy. I will miss him!"