Description 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 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 socket shades one in orange, and the other two are missing. 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 two swivelling shutters, which are both missing, and the back sight vane has one pinhole. An ivory pencil head is fitted in the crossbar, however the pencil is missing. The octant is contained in a stepped oak box painted brown.

The instrument has an inlaid ivory scale from -2° to 94° by 20 arcminutes, measuring to 89°. The octant has an ivory vernier measuring to 1 arcminute, with zero at the right.