The octant has a mahogany 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 and on the back of the frame, which are both loose. There is no tangent screw and the clamping screw is located on the back of the index arm. The octant has three socket shades, one green, and two red. Index-glass adjustment is made by a screw and on both horizon glasses are by levers, wing nuts and milled clamping screws. The sight vane has two pinholes and a swivelling shutter, whereas the back sight vane has one pinhole. A pencil or screwdriver is missing from the crossbar. The octant is contained in a damaged wooden keystone box, painted or varnished on the outside, and painted red on the inside.

The instrument has an inlaid ivory scale from -4° to 94° by 20 arcminutes, measuring to 90°. The octant has an ivory vernier measuring to 1 arcminute, with zero at the centre.