Ramsden Library Telescope

Signature

Je Ramsden , London

Date

circa 1785

Number of Draws

Dimensions

English

Metric

Main Tube Length

25.8in

654mm

Main Tube Diameter

2.6in

65mm

Total Length

41.0in

1041mm

Closed Length

37.5in

953mm

Objective Clear Aperture Diameter

2.2in

57mm

Description

This telescope has a round parallel lacquered brass barrel. The objective lens is an achromatic doublet with a push-on cap. It has a single brass draw with rack and pinion focusing by a thumbwheel. There is a separate terrestrial eyepiece tube, which screws into the collar at the end of the drawtube. It has four lenses and a slightly flared eyecup. The astronomical eyepiece tube is missing. It is boldly signed "Ramsden London" on the side of the barrel, with the eyepiece to the left. Within the "R" are the letters "Je", short for Jesse. The telescope is mounted on a folding brass cabriole tabletop stand, that has a stabilizing bar with a rack and pinion adjustment. It has a fitted mahogany case. Jesse Ramsden is considered to be one of the finest instrument makers of the late 1700s.

College of Optical Sciences
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