A sextant or small telescope eyepiece from the 1845 British Northwest Passage Expedition led by Sir John Franklin. This is the larger eyepiece that screws over the tube and has black (smoked) glass. The smaller eyepiece (AAA2141.1) is fitted with a clear lens that screws into the telescope or sextant tube.

The two eyepieces were found by Lieutenant William R. Hobson's sledge team on 3 May 1859 under a small collapsed tent, possibly for the officers, at an abandoned camp site at Cape Felix, King William Island, as part of the search expedition led by Captain F. L. McClintock. Hobson described them '...two eye pieces of small telescopes,..' [Stenton, 'Arctic' v.69, No. 4, p. 514]. McClintock recorded them as 'two eye pieces of sextant tubes' [McClintock, 'Voyage of the Fox' (1860), p.368]. The camp site was occupied by about twelve officers and men from the Franklin expedition during the summer of 1847, living in three small tents. They were probably engaged in surveying, scientific work or hunting while the expeditions ships remained trapped in the ice. The site was apparently abandoned in a hurry - Hobson found the tents flattened with blankets and bear skins underneath. He concluded that, as the party had left behind so much of their equipment, they had probably gone back to the ships.

The eyepieces were displayed at the Royal Naval Museum, Greenwich, in Case 2, No. 19 'Eye-pieces of sextant'. The item is also shown in 'Stereoscopic slides of the relics of Sir John Franklin's Expedition' photographed by Lieutenant Cheyne RN, at the United Services Museum, Whitehall, No. 11 (bottom left).