The backstaff is made from a hornbeam frame with boxwood arcs. The staff has an inlaid ivory plate on the main strut and rivets capped by decorative ivory triangles. There are no vanes. Small decorative stamps, including flowers and fleurs-de-lis, are stamped at the ends of both arcs.

The transversal scale on the thirty degree arc is from 0° to 25° by 5 arcminutes and reads to 0.5 arcminutes. The graduation on the sixty degree arc is from 0° to 65° by 1°.

Object Details

ID: NAV0033
Collection: Astronomical and navigational instruments
Type: Backstaff
Display location: Display - ROG
Creator: Unknown
Date made: circa 1750
People: Davies, John
Credit: National Maritime Museum, Greenwich, London
Measurements: Overall: 20 mm x 640 mm x 353 mm
Parts: Backstaff

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