In the August 1992 episode of The Sky at Night, historian Colin Ronan joined Patrick Moore to discuss the long history of the telescope and uncover one of the tale's forgotten figures.
The principles behind the telescope were first developed in the 13th century, when British natural scientist Robert Grosseteste observed how light was bent as it passed through a water-filled flask. In his book De Iride, he noted: “This part of optics… shows us how we may make things a very long distance off appear as if placed very close and large near things appear very small.”
His colleague Roger Bacon realised that mirrors could also be used, but the limits of glassmaking at the time prevented either method from being usefully deployed. The usual story is that the…
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BBC Sky at Night United Kingdom (Digital) - 1 Issue, August 2024