Ramsden eyepiece

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Ramsden eyepiece

See eyepiece.

Ramsden eyepiece

[′ramz·dən ′ī‚pēs]
(optics)
An eyepiece consisting of two planoconvex lenses with their plane sides facing outward, having the same power and focal length, and separated by a distance equal to their common focal length.
References in periodicals archive ?
Jesse Ramsden, a London instrument-maker, made The GreatTheodolite, delivered in 1787, weighing 200 Ibs, with a brass scale three feet across and capable of measuring to one second of arc, a 3,600th of a degree.
Harris suggests that it was Magellan who attempted to place the Danish instrument-maker Jesper Bidstrup with a British maker like Jesse Ramsden.