Reflecting telescope, 20-inch aperture with speculum mirror and altazimuth mounting, by James Nasmyth at Patricroft, Manchester, England, 1850-1852. Later the instrument was moved to ‘Hammerhurst’, Nasmyth’s new home at Penshurst, Kent, when he retired from industry in 1856. (see note)

James Nasmyth, a successful entrepreneur built this reflecting telescope at his foundry at Patricroft near Manchester around 1850. With a 20-inch metal mirror, it originally had an optical configuration with the eyepiece perilously located at the top of the tube. To improve matters, Nasmyth lengthened the light path so that it was directed through trunnion axis of the turntable stand. As Nasmyth was observing the Sun and the bright Moon, the additional reflection off the extra mirror was not a problem. From drawings of the Moon made at the telescope, he made relief models of the lunar surface. These were then photographed with suitable lighting to produce results better at the time than could be achieved with direct lunar photography.