The octant has an ebony frame and limb with a brass index arm and fittings, and an inlaid ivory plate on the crossbar. The tangent screw and clamping screw are positioned on the back of the index arm. The octant has three socket shades, two red andone 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 square-headed screw, a detached key, a lever, worm gear and a milled clamping screw. Attached to the octant is a threaded, non-adjustable telescope bracket, as well as a swivelling sight vane with one pinhole. The telescope is 83 mm in length, and has an erect image. The sight-tube is 79 mm in length and has a red shaded eyepiece, an adjusting key and a magnifying glass, which is missing. The octant is contained in a wooden keystone box.

The instrument has an inlaid ivory scale from -3° to 109° by 30 arcminutes, measuring to 90°. The octant has an ivory vernier measuring to 1 arcminute, with zero at the right.