The octant has an ebony frame and limb with a brass index arm and fittings. It has inlaid ivory plates on the crossbar and on the back of the frame. The tangent screw and clamping screw are on the back of the index arm. The octant has three index shades in red, orange, and green. Index-glass adjustment is made by a screw and on the horizon glass by a lever, wing nut and a milled clamping screw. The sight vane, whose holding screw is missing, has two pinholes and a swivelling shade in red. An ivory pencil head is fitted in the crossbar, however the pencil is missing. The octant is contained in a keystone oak box with a stepped lid. In the lid is a trade label for ‘J. Hughes, 38 Queen Street, Ratcliffe Cross, London’.

The instrument has an inlaid ivory scale from -2° to 100° by 20 arcminutes, measuring to 100°. The octant has an ivory vernier measuring to 1 arcminute, with zero at the right.