The octant has an ebony frame, mahogany limb, and a brass index arm. It also has brass fittings, a brass stop for the 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 on the back of the index arm. The octagon has three socket shades, two red and one green. Index-glass adjustment is made by a screw and 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 has one pinhole. The sight vane’s foot, a foot of the frame, the shutter and various screws are replacements. An ivory pencil head is fitted in the crossbar, though the pencil is now missing. The octant is contained in a stepped box, painted blue on the outside and cream on the inside. The box contains in the lid a trade label for ‘Henry Hughes and Son, 59 Fenchurch Street, London’ and a handwritten label ‘Helen, Francis, Isabel, Gordon, & Pauline gave this instrument to Father Christmas 1908’.

The instrument has a surface-mounted brass scale from -5° to 95° by 20 arcminutes, measuring to 89°. The octant has a brass vernier measuring to 1 arcminute, with zero at the centre.