Clifton Observatory

Clifton Observatory is a former windmill, now functioning as a camera obscura, built in the 18th century. The camera and an extension were added in 1828 and 1835 by a Mr. West. The structure is made of Carboniferous limestone rubble with limestone dressings and features a lead roof on the tower, while the side block is roofless. It has a single-depth plan and consists of a three-stage round tower alongside a single-storey, four-window side block. The tower has a battered design with a first-floor casement window and tall, moulded brackets supporting a rendered top storey that houses the camera obscura, which is adorned with crenellations and casements in the embrasures. There is a Tudor-arched doorway leading to the roofless side block, which has a curved end and two segmental-headed windows. The rear of the side block features two four-centre arched windows with torus mouldings and casements with margin panes, as well as paired right-hand two-light windows.

Inside, there is a winding stair that leads up to the camera obscura in the roof and down into a tunnel that connects to Ghyston's Cave, located in the side of the gorge. Historically, the windmill was damaged by fire in 1777, and William West leased it for conversion into an observatory in 1828. In 1835, he was granted additional land next to the tower, where he constructed a new astronomical observatory with a revolving dome and telescope to facilitate unrestricted observation of the heavens. Adjacent to this was a large room containing various astronomical maps, globes, and instruments, which was intended for occasional use as a lecture room. The tower was also modified in 1835 with the rebuilding of the wooden balcony and the installation of the camera obscura. West excavated an underground passage to Ghyston's Cave, which opened in 1837.