making binoculars?

General Joy

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If one came across a bunch of old glasses (an assortment), would it be possible to make a pair of binoculars out of them? They don't have to be fancy or even look like binoculars as we know them, but just as long as they would work at greatly magnifying objects in the distance...

(I know nothing about optometry and how exactly lenses work!)

Thanks!
 

benbradley

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It seems plausible to make a crude-but-effective telescope (maybe like Galileo had, that you can see the moons of Jupiter with). A "moderate" eyeglass might have a focus length of two or three feet, and that would be the objective. The eyepiece would probably need several lenses held together to work.

You couldn't reasonably make binoculars, mainly because you need the prisms to move the main lenses farther apart than the eyes. I suppose you could make two side-by-side telescopes, but the resulting 3d image would be almost perfectly flat.

Your answer: Yes, sort of.:)
 

Kathie Freeman

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The problem is, well at least two problems:
Eyeglass lenses are not round, and lenses from different pairs are different shapes so there would be a lot of distortion.

The lenses would all have to be for a near-sighted person or persons, and the prescriptions for the two sides would have to be fairly closely matched which most people's eyes aren't if they need glasses.

The focusing problem could be (theoretically) solved by putting sliding tubes together, but wouldn't it be easier to make a telescope using a couple of magnifying glasses? Binoculars are awfully complicated.