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

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.