Selection of twenty six eyepieces, in wooden mounts inscribed D1 to D26, no lens visible in D25 (possibly slipped between brass plates)

Dated 1780-1800, this selection of 26 eyepieces was made by the astronomer, William Herschel for the telescopes he used. In addition to building his own reflecting telescopes, Herschel made his own eyepieces. In most cases, he mounted the optics in cocoa a tropical hardwood still used for woodwind instruments today. Herschel's use of wood instead of brass is probably due to his background as a musician. These eyepieces are also unusual in that they have very short focal lengths to produce massive magnification. By using a tiny single lens, Herschel achieved powers in excess of several thousand times. Such high values of magnification were doubted by many of Herschel's contemporaries and are extraordinary even today.