Ebony and brass octant.

Made:
1790-1800 in Wapping
maker:
Thomas Ripley & Son

Octant made by Thomas Ripley and Son, London, about 1795. Ebony frame and limb with brass index arm and fittings; inlaid ivory plates on the crossbar and the back of the frame. Signed on the plate on the crossbar: Made by Tho.s Ripley & Son Hermitage Bridge | London. Marked on the scale (stamped) [fleur-de-lis]. Inlaid ivory scale from -2° to 99° every 20', measuring to 89°. Ivory vernier to 1', zero at the right. The tangent screw is on the front of the index arm; the clamping screw is on the back. Three socket shades (two red, one green). Index-glass adjustment by screw; adjustment of the horizon glass by lever and worm gear by square-headed screw and a detached key (missing); adjustment of the back horizon glass by lever, wing nut and clamping screw (missing). The sight vane has two pinholes and a swivelling shutter; the back sight vane has one pinhole. A pencil or screwdriver is missing from the crossbar. No box.

Details

Category:
Astronomy
Object Number:
1939-38
Materials:
brass, complete, ebony, ivory
Measurements:
overall (estimate): 100 x 380 x 460 mm
type:
octant
taxonomy:
  • furnishing and equipment
  • measuring device - instrument
credit:
Major E.O. Henrici
status:
Permanent collection

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