Ebony and brass octant.

Ebony and brass octant.

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Science Museum Group Collection
© The Board of Trustees of the Science Museum

Octant made by John and Edward Troughton, London, about 1800, for Sir George Shuckburgh, Bart. (1751-1804). Ebony frame and limb with a brass index arm and fittings; inlaid ivory plates on the crossbar and on the back of the frame. Signed at the bottom of the index arm: Troughton London. Inlaid ivory scale from -2° to 101° every 20', measuring to 90°. Ivory vernier to 1', zero at the right. The tangent screw and clamping screw are on the back of the index arm. Three shades (two red, one green); no horizon shades. Index-glass adjustment by screw; adjustment of the horizon glass by screw, lever, wing nut and a milled clamping screw. The sight vane has two pinholes and a swivelling shade (red). A pencil or screwdriver is missing from the crossbar. In a stepped oak keystone box, painted brown on the outside. Trade labels (taken from the box) for J. and E. Troughton, 136 Fleet Street, London (1788-1804) and for Ripley's, Mill Place, Commercial Road, London.

Details

Category:
Navigation
Object Number:
1933-11
Materials:
ivory and ebony
type:
octant and trade card
credit:
British Astronomical Association

Parts

Ebony and brass octant.

Ebony and brass octant.

Hadley's quadrant, 9 3/4 inch, made for Sir George Shuckburgh, Bart., by Troughton. In fitted case (lid cracked) with key. Ivory pencil holder missing.

Object Number:
1933-11/1
type:
octant
Image ©
The Board of Trustees of the Science Museum

J & E Troughton trade card

Trade card: J & E Troughton, 136 Fleet Street, London from case for Hadley's quadrant

Object Number:
1933-11/2
type:
trade card
Image ©
The Board of Trustees of the Science Museum