The octant has an ebony frame and limb with a brass index arm and fittings. It also has inlaid ivory plates on the crossbar and on the back of the frame. The tangent screw and clamping screw are positioned on the back of the index arm. The octant has three socket shades in red, orange, and green, and three horizon shades, two red, and one green. Index-glass adjustment is made by a screw and on the horizon glass by a lever, worm gear and a milled clamping screw. The sight vane has two pinholes and a red swivelling shade. The octant has no box.

The instrument has an inlaid ivory scale from -3° to 108° by 20 arcminutes, measuring to 92°. The octant has an ivory vernier measuring to 1 arcminute, with zero at the right.