Astronomer Dr David Whitehouse told Sky News that Sir Patrick Moore had "loved astronomy more than he loved himself".
He was passionate, he was dedicated and had an unselfish love of astronomy and he passed that on to everybody who knew him and he came across. He was a difficult person personally to deal with on many occasions, he was sometimes awkward, truculent, stubborn but that was Patrick, that was part of his remarkable personality which so many people came to enjoy and love.
I think many people realised he was a unique person.
He was not a professionally trained astronomer and yet did professional quality work, particularly when it came to mapping the Moon in the 1950s - I think every astronomer in the world owes something to Patrick Moore.
More top news
A picture of Cecil the lion - the animal killed by an American dentist in Zimbabwe - has been projected on to the Empire State Building.
A man, believed to be in his 50s, was pronounced dead at the scene after apparently suffering a heart attack.
A healthy retired nurse has ended her life at a Swiss suicide clinic because she did not want to become old.