Gregorian secondary mirror

A circular concave mirror made as a secondary mirror for a Gregorian telescope. This secondary mirror has a brass mount and a brass cover. It has a good polish.

William Herschel made and used Gregorian telescopes before moving on to Newtonian and later Herschelian (to his own design) telescopes.

Object Details

ID: AST0834
Collection: Astronomical and navigational instruments
Type: Gregorian secondary mirror
Display location: Not on display
Creator: Herschel, William
Date made: circa 1773
Credit: National Maritime Museum, Greenwich, London, Herschel Collection
Measurements: Overall: 16 mm; Diameter: 26.67 mm