'Leviathan'. Engraving of the 'Leviathan of Corkstown', completed by William Parsons, 3rd Earl of Rosse (1800-1867) on his home estate in Ireland in 1845. At the time it was the world's largest telescope, having taken 12 years to build at a cost of #12,000. It had a 183 centimetre (72- inch) diameter mirror, weighed 4060 kg and had a tube over 15 m long. It was supported by a complex system of platforms, pulleys and chains. It was protected from high winds by two masonry piers which restricted the viewing. With it Rosse identified a spiral galaxy's true nature and went on to find 15 of them. Poor weather hampered further observations. It was dismantled in 1908.