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) by James Nasmyth (1808-1890), taken 1858-1864, which originates from his 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.