John Wall
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Stargazing Live: Astronomy invention given away free

A retired engineer who revolutionised amateur astronomy has revealed that he gave away an invention for free.

John Wall, from Coventry, created the Crayford Focuser, allowing cheap, smooth focusing of a telescope.

He said: "I don't get any royalties for it but I don't care... The fact is it's all over the planet now."

Stargazing Live celebrates astronomy on BBC Two on Tuesday evening.

Speaking about the invention, presenter Mark Thompson said: "It's really revolutionised amateur astronomy because it's given amateurs the chance to do some really top quality imaging."

BBC Midlands Today science correspondent David Gregory-Kumar reports.