Leviathan of Parsonstown
Townparks, Ireland · built 1845
The Leviathan of Parsonstown, or Rosse six-foot telescope, is a historic reflecting telescope of 72 inches (1.83 m) aperture, which was the largest telescope in the world from 1845 until the construction of the 100-inch (2.5 m) Hooker Telescope in California in 1917. The Rosse six-foot telescope was built by William Parsons, 3rd Earl of Rosse on his estate, Birr Castle, at Parsonstown (now Birr) in Ireland.
Observatory data from Wikidata (CC0). Summary from Wikipedia (CC BY-SA).