Ramsden, Jesse (1735–1800), British instrument maker. Ramsden was a pioneer in the early invention and manufacture of precision instruments. He designed improved, highly accurate sextants and theodolites. He introduced the Ramsden eyepiece in 1779.
Medical Dictionary
Ramsden eyepiece
noun Rams·den eyepiece \ˈramz-dən-\
Medical Definition of RAMSDEN EYEPIECE
: a nearly achromatic optical system that contains two plano-convex lenses with the convex surfaces facing each other and is used especially in instruments fitted with micrometer wires or a scale
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