The sextant has a polished brass straight-bar pattern pillar frame, with twenty-four pillars, and a wooden handle. The tangent screw and clamping screw are located on the back of the index arm. The sextant has three shades in red, orange, and green, and three horizon shades in red, orange, and green. Index-glass adjustment is made by a screw and on the horizon glass by screws and a thumbscrew. Attached to the sextant is a telescope bracket, which is now missing, with perpendicular adjustment by a rising-piece and a milled knob. The telescopes and other parts are missing. The sextant has no box.

The instrument has a polished brass scale from -5° to 148° by 20 arcminutes, measuring to 127°. The sextant has a brass vernier measuring to 20 arcseconds, with zero at the right.

Edward Troughton patented the pillar and plate frame (no. 1644 of 1788), which provided rigidity but was not too heavy.