Sextant

The sextant has an anodized brass frame and a wooden handle. A white ivorine micrometer drum, a pressure clamp and a worm screw are positioned at the bottom of the index arm. The sextant has four green shades and three green horizon shades. Index-glass adjustment is made by a capped square-headed screw and a separate spanner. Adjustment on the large round horizon glass is made by a capped square-headed screw and a detached spanner.

Attached to the sextant is a threaded telescope bracket in two parts, fitted for correcting collimation error. It has perpendicular adjustment made by a rising-piece and a milled knob. The telescope is 103 mm in length with an erect image. A second telescope is 76 mm long with an erect image. The sight-tube is 83 mm in length and accompanies the sextant along with a spanner, a green shaded eyepiece, and a brush.

This instrument has a polished brass scale from -5° to 137° by 0.5 arcminutes, measuring to 132°. Micrometer to 0.5 arcminutes

The sextant is contained in a square fitted wooden box, with a metal trade label in the lid for C. Plath, Hamburg, Stubbenhuk 25. The box contains a Kelvin Hughes certificate of examination, dated 18 April 1955, and a trade label for Lilley and Reynolds, London.

Object Details

ID: NAV1250
Collection: Astronomical and navigational instruments
Type: Sextant
Display location: Not on display
Creator: Plath, C.
Date made: circa 1925
Credit: National Maritime Museum, Greenwich, London
Measurements: Overall: 170 x 300 x 30 mm; Radius: 159 mm
Parts: Sextant