Mural quadrant

Bradley's quadrant follows the same design as Halley's, the main difference being the metal used. After twenty years of use, the frame of Halley's iron quadrant had buckled under its own weight and become inaccurate. Bradley made his quadrant from brass, a lighter material, in order to overcome this problem. Bradley's quadrant also has an arc which has been hand-divided and signed by one of the great instrument makers of the day, John Bird.

See, John Bird, The Method of Constructing Mural Quadrants, ...Published by Order of the Commissioners of Longitude, 1768.

Carole Stott, 'The Greenwich Meridional Instruments (up to and including the Airy Transit Circle)', Vistas in Astronomy, 28, (1985), pp. 133-145

Object Details

ID: AST0971
Collection: Astronomical and navigational instruments
Type: Telescope
Display location: Display - ROG
Creator: Bird, John
Date made: 1750
Credit: National Maritime Museum, Greenwich, London
Measurements: Overall: 2438 mm
Parts: Mural quadrant

Your Request

If an item is shown as “offsite”, please allow eight days for your order to be processed. For further information, please contact Archive staff:

Tel: (during Library opening hours)

Click “Continue” below to continue processing your order with the Library team.