Diamond- pattern frame sextant.

Made:
1835-1845 in Fleet Street
maker:
Troughton and Simms Limited
Sextant made by Edward Troughton and William Simms, London

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Sextant made by Edward Troughton and William Simms, London
Science Museum Group Collection
© The Board of Trustees of the Science Museum

Polished brass sextant, diamond-pattern frame type, with polished brass limb wooden handle and threaded hole for stand with shaped mahogany case by Troughton and Simms, Fleet St., City of London, England, 1835-1845. Consists of inlaid 129° silver scale (-45° to 150°) with 10' divisions, vernier scale (10") two sets of filter shades (4 & 3, red & green) and reading magnifier on a swivel arm (70mm). Fitted with threaded telescope bracket with collimation correction for two telescopes, 73mm & 180mm (erect & inverted images) and sighting tube (82mm). Case contains manuscript list of contents, bequeathed by S. Radford, June 1900.

Details

Category:
Navigation
Object Number:
1900-174
Materials:
brass (copper, zinc alloy), glass and wood (unidentified)
type:
sextant
credit:
Dr. W T Radford

Parts

Sextant made by Edward Troughton and William Simms

Sextant made by Edward Troughton and William Simms

Sextant made by Edward Troughton and William Simms, London, about 1840. Polished brass diamond-pattern frame and polished brass limb, a wooden handle with a threaded brass hole for fitting it on a stand. Signed on the limb: Troughton & Simms, London. Marked on the index arm: V & A . Mus. Inlaid silver scale from -45° to 135° every 10', measuring to 129°. Silver vernier to 10", zero at the right. The tangent screw and clamping screw are on the back of the index arm. Four shades (three red, one green); three horizon shades (two red, one green). Index-glass adjustment by screw; adjustment of the horizon glass by a screw and a capstan screw. Magnifier on a 70-mm swivelling arm; the magnifier is fitted in a brass disc that is painted white on the back for reflection. Threaded telescope bracket in two parts, fitted for correcting collimation error; perpendicular adjustment by rising-piece and a milled knob. Telescope (73 mm) erect image; telescope (180 mm) inverted image, two parallel cross-wires; extra draw tube (70 mm) inverted image, two parallel cross-wires. Shaded eyepiece (red), an adjusting pin; the magnifying glass is missing.

Measurements:
overall: 280 mm x 345 mm x 145 mm, 430 mm, 1.65kg
Materials:
brass (copper, zinc alloy) , wood (unidentified) , glass and steel (metal)
Object Number:
1900-174/1
type:
sextant
case for 8"sextant, with key, made by Troughton and Simms

case for 8"sextant, with key, made by Troughton and Simms

Shaped mahogany box for sextant made by Edward Troughton and William Simms, London, about 1840. Containing in the lid a MS list of contents, and stuck on the outside of the lid a MS label: Sextant | Bequeathed by S. Radford | June 1900.

Materials:
wood (unidentified)
Object Number:
1900-174/2
type:
case