The octant has an ebony frame and limb with a brass index arm, fittings, and a brass stop for the index arm. It also has inlaid ivory plates on the crossbar, which is missing, and on the back of the frame. There is no tangent screw, and the clamping screw is located on the back of the index arm. The socket shades are missing. Index-glass adjustment is made by a screw and on both horizon glasses, with one glass missing, by levers, wing nuts, and milled clamping screws, one of which is also missing. The sight vane has two pinholes and a swivelling shutter, whereas the back sight vane is missing. One foot is missing from the frame and the right strut is cracked. The octant has no box.

The instrument has an inlaid ivory scale from -1° to 99° by 20 arcminutes, measuring to 90°. The octant has an ivory vernier measuring to 1 arcminute, with zero at the right.