Leviathan of Parsonstown, Birr

Leviathan of Parsonstown, or Rosse six-foot telescope, is a historic reflecting telescope of 72 inches aperture, which was the largest telescope in the world from 1845 until the construction of the 100-inch 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. ()