The octant has an anodized brass plain-pattern-frame and a wooden handle. The tangent screw and clamping screw are located on the back of the index arm. The octant has four shades, three red and one green and three horizon shades, two red and one green. Index-glass adjustment is made by a screw and on the horizon glass by capstan screws. Attached to the octant is a magnifier on an 82mm swivelling arm as well as a threaded, non-adjustable telescope bracket. The telescope is 83 mm in length with an erect image. The sight-tube is 81 mm in legth and has a red shaded eyepiece and an adjusting pin. The octant is contained in a mahogany keytone box, with a trade label in the lid for Henry Hughes and Son, 59 Fenchurch Street, London (after about 1875).

The instrument has a bronzed limb with an inlaid ivory scale from -5° to 120° by 20 arcminutes, measuring to 102°. The octant has an ivory vernier measuring to 30 arcseconds, with zero at the right.