This achromatic telescope has a tapering mahogany barrel and a single brass draw tube. The other brass fittings include an objective lens cap and a pivoted eyepiece cover. The barrel has an engraved table attached to it with a sliding cover decorated with a royal crest. Beside the table is a square piece of ivory to be used as a notepad. The maker's name is inscribed on the draw tube: ‘Made & Sold by Wm. WATKINS, / St. James’s Strt. LONDON.’.

The instrument follows a design patented by Cater Rand in 1799 (patent number 2289) for an ‘Improved military and naval telescope'. The screw beside the eyepiece moves two pairs of cross hairs together and apart. To find the distance of an object, these are moved until they are at the top and bottom of the observed object. You then read off the angle subtended on the scale beside the eyepiece using the pivoted magnifying glass attached to the eyepiece. You then use the table on the barrel to work out the distance of the object based on its known height and the angle observed.