The sextant has a polished brass straight-bar pattern pillar frame, with eighteen pillars, a protective frame over the fittings and mounts, and a wooden handle. The tangent screw and clamping screw are positioned on the back of the index arm. The sextant has four shades, three red, and one green, and three horizon shades, two red and one green. Index-glass adjustment is made by a screw and on the horizon glass by a capstan screw.

Attached to the sextant is a threaded telescope bracket with perpendicular adjustment made by a rising-piece and a milled knob. There is also a magnifier travelling on a worm screw with a milled knob. The telescope is 133 mm in length with an inverted image. It has a rotating shaded eyepiece with three shades, two red and one orange. A second telescope is 175 mm in length with an inverted image and four cross wires. The sight-tube is 89 mm in length and has an adjusting pin. The sextant is contained in a shaped mahogany box.

The instrument has a polished brass limb with inlaid gold scale from -2° to 135° by 15 arcminutes, measuring to 122°. The sextant has a gold vernier measuring to 20 arcseconds, with zero at the right.

Edward Troughton patented the pillar and plate frame (no. 1644 of 1788).