The octant has an ebony frame and limb with a brass index arm and fittings. It also has an inlaid ivory plate on the crossbar. There is no tangent screw, and the clamping screw is on the back of the index arm. The octant has three index shades, two red and one green. Index-glass adjustment is made by a screw, whereas on the horizon glass it is by a lever, wing nut and a milled clamping screw. The sight vane has two pinholes and a swivelling shutter. An ivory cap for a pencil, which is missing, is fitted in the crossbar. The octant is contained in a keystone mahogany box with a modern, plywood lid top.

The instrument has an inlaid ivory scale from -3° to 108° by 20 arcminutes, measuring to 89°. The octant has an ivory vernier measuring to 1 arcminute, with zero at the right.