The octant has an ebony frame and limb with a brass index arm, fittings, and a wooden handle. It also has an inlaid ivory plate on the crossbar. The tangent screw and clamping screw are located on the back of the index arm. The octant has three shades, two 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 milled knob, lever, worm gear and a milled clamping screw. Attached to the octant is a threaded telescope bracket without adjustment, and a swivelling sight vane with one pinhole. The telescope is 83 mm in length with an erect image. The octant has no box.

The instrument has an inlaid ivory scale from -4° to 109° by 20 arcminutes, measuring to 91°. The octant has an ivory vernier measuring to 1 arcminute, with zero at the right.