This is one of the few American-made telescopes in the Museum’s collection. It has a silvered brass barrel covered in leather and three draw tubes. The eyepiece has an unusual mechanism allowing four lenses, three of which are coloured, to be changed via a small thumbwheel.

The objective end of the telescope is fitted with a range-finding device, including a scale bar across the objective lens. An inscription around this fitting indicates the calculations required to use it for range finding. There are also removable caps for the objective lens and for the rotating scale for the rangefinder. The maker's name is engraved on the objective end of the telescope: 'EDWD KAHLER WASHINGTON D.C. U.S.A.'

The instrument still has its original pine box. It once belonged to Prince Alfred, Duke of Edinburgh (1844-1900), who served in the Royal Navy for many years and whose name is inscribed on the lid of the box. It was presented to the Museum by Queen Mary in 1936.