The octant has an ebony frame, limb and index arm with the lower end of the arm made of brass. It also has brass fittings, a brass stop for index arm, and inlaid ivory plates on the crossbar 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 octant has three socket shades in green, orange, and red. Index-glass adjustment is made by a screw and on both horizon glasses 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 an oak keystone box with a stepped lid.

The instrument has an inlaid ivory scale from -5° to 95° by 20 arcminutes, measuring to 91°. The octant has an ivory vernier measuring to 1 arcminute, with zero at the centre.