One of three calotype prints mounted together on a single board , showing three different views of Warren De la Rue's 13-inch reflecting telescope with speculum mirror on a clock driven German type equatorial mounting at his observatory at Cranford, Middlesex. All taken by James Nasmyth and separated from his original album.

Photograph (calotype print) taken by James Nasmyth (1808-1890), 1858-1864, which originates from his own album. The calotype print shows Warren De La Rue's (1815-1889) 13-inch reflecting telescope in its observatory at Cranford, Middlesex in England. A pioneer of astrophotography, De La Rue used this telescope to take a series of early photographs of the Moon. A difficult task, as the then available wet collodion plates were insensitive to light compared to modern films. This required exposures of several minutes through his telescope using a clock-driven equatorial mounting.