The octant has an ebony frame and limb with a brass index arm and fittings, a wooden handle, 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 four socket 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 lever, worm gear and a milled clamping screw. Attached to the octant is a threaded, non-adjustable telescope bracket without. The telescope is 89 mm in length, and has an erect image. The sight-tube is 81 mm in length and has a red shaded eyepiece and a magnifying glass, which is missing. The octant is contained in a wooden keystone box.

The instrument has an inlaid ivory scale from -2° to 107° by 20 arcminutes, measuring to 93°. The octant has an ivory vernier measuring to 1 arcminute, with zero at the right.