The octant has an ebony frame and limb with a brass index arm, fittings, and a stop for the index arm. It also has inlaid ivory plates on the crossbar and on the back of the frame. There is no tangent screw, and the clamping screw is on the back of the index arm. The octant has three index shades, one of which is red, and the other two are missing. The index glass is fixed , and the horizon glass is adjusted by a lever, wing nut and a milled clamping screw. The sight vane has two pinholes and a swivelling shutter. A pencil or screwdriver is missing from the crossbar. The octant has no box.

The instrument has an inlaid ivory scale from -5° to 99° by 20 arcminutes, measuring to 91°. The octant has an ivory vernier measuring to 1 arcminute, with zero at the right.