Brass framed pocket sextant.

Pocket sextant made by John Dollond, London, about 1800 Brass framed pocket sextant.

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Pocket sextant made by John Dollond, London, about 1800
Science Museum Group
© The Board of Trustees of the Science Museum

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

Pocket sextant made by John Dollond, London, about 1800. Lacquered brass frame and limb, a hinged wooden handle. Signed on the index arm: Dollond London. Inlaid silver scale from -2° to 154° every 30', measuring to 129° (digits read from the pivot). Silver vernier to 1', zero at the left. There is no tangent or clamping screw; the index arm is moved by a milled knob along a rack on the back of the limb. One shade (red). Index- and horizon-glass adjustment by screws. Magnifier (single lens) on a 25 mm swivelling arm. Telescope bracket without adjustment. Telescope (43 mm) erect image, a sliding shade (red). With box.

Details

Category:
Navigation
Object Number:
1952-195
Materials:
brass (copper, zinc alloy), wood (unidentified), silver (metal), glass and mirror-glass (silvered)
Measurements:
overall: 180 mm x 105 mm x 70 mm, .26kg
type:
pocket sextant
credit:
J H Steward Limited

Parts

Box for brass framed pocket sextant.

Box for pocket sextant made by John Dollond, London, about 1800.

Object Number:
1952-195/1
type:
pocket sextant
Image ©
The Board of Trustees of the Science Museum