View your list of saved words. (You can log in using Facebook.)
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
Biographical Note for RAMSDEN EYEPIECE
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.