Portable telescope

This is not a complete telescope, it is four draw tubes from a larger example. The surviving tubes are made of vellum, while the brass fittings include a sliding eyepiece cover. Stop lines, mostly rings of dots, on the draw tubes, indicate the optimum working length of the telescope. The barrel and objective lens, and perhaps some other draw tubes, are missing. This would have been a non-achromatic telescope.

Object Details

ID: NAV1597
Collection: Astronomical and navigational instruments
Type: Portable telescope
Display location: Not on display
Creator: Unknown
Date made: circa 1750
Credit: National Maritime Museum, Greenwich, London
Measurements: Overall: 270 mm; Diameter: 38 mm
Parts: Portable telescope