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The point at which at which light rays passing through a lens come together
A lens that is thicker at the edges than it is in the middle
The light sensitive area at the back of the eye
A mirror that curves out ward
An instrument for viewing distant objects that used a curved mirror at the of it's tube to gather light
A microscope that uses a signal lens to magnify objects
A viewing instrument that magnifies objects thousands of times by using a beam of electrons