Herschel's 20 ft Telescope Photo Gallery:

Camera Lucida sketch of Herschel's 20 ft. telescope in situ at Feldhausen, 1834.
Courtesy of Africana Museum. (Source: Moore; Evans

20 foot telescope at Feldhausen.
Source: Warner, Maclear

The 20 feet camera in the process of dismanteling, Febr. 1838.
Source: Warne - Lady Herschel.