Evidence suggests ancient civilizations, including the Greeks, may have had early optical knowledge and devices like ...

Instead of a concave lens near the eye ... This was the first working reflecting telescope. Other designers proved unable to grind mirrors with a regular curvature, so the reflector remained ...

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He replaced the concave lens with a second convex ... Light travels into the telescope, bounces off a curved mirror at the bottom which aims it all into a focal point, where it hits a mirror ...