William Herschell's 40 Foot Telescope 18th Century Poster

A nice item for someone who is interested in astronomy and historical scientific equipment, star study and observatories this is "William Herschel's 40-foot telescope, also known as the Great Forty-Foot telescope, was a reflecting telescope constructed between 1785 and 1789 at Observatory House in Slough, England. It used a 48-inch (120 cm) diameter primary mirror with a 40-foot-long (12 m) focal length (hence its name "Forty-Foot"). It was the largest telescope in the world for 50 years. It may have been used to discover Enceladus and Mimas, the 6th and 7th moons of Saturn. It was dismantled in 1840; today the original mirror and a 10-foot (3.0 m) section of the tube remain." This is a high dpi scan of an original copperplate engraving by Andrew Bell 1726-1809 who was and engraver and printmaker. This print was featured in the very early editions of Encyclopaedia Britannica and most likely the first edition.