The quintant has an anodized brass straight-bar pattern pillar frame, with twenty-four pillars, and a wooden handle with a brass-lined hole for placing it on a stand. The tangent screw and clamping screw are positioned on the back of the index arm. The instrument has four shades in red and green, but two are missing. It also has three horizon shades, two red and one green. Index-glass adjustment is made by a screw and on the horizon glass by a square-headed screw and a detached key.

Attached to the quintant is a magnifier on a 95mm swivelling arm. There is also 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. Accompanying the instrument is a blue shaded eyepiece. The telescopes, adjusting key and some unidentified parts are missing.

The instrument has a polished brass limb with an inlaid silver scale from -5° to 160° by 10 arcminutes, measuring to 137°. The quintant has a silver vernier measuring to 10 arcseconds, with zero at the right. The digits seem very modern for the date of this instrument.

The quintant is contained in a mahogany keystone box.

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