Rosse, William Parsons, 3rd Earl of 1800-67
Irish astronomer and landowner

Born in York, England, he was educated at Trinity College, Dublin, and Oxford, where he graduated in mathematics (1822). With the help only of the workers on his feudal estate of Birr Castle at Birr (then Parsonstown) he constructed on the model of Sir William Herschel's instruments a gigantic metal-mirror telescope, the 'leviathan of Parsonstown'. With this, the largest telescope before the construction of the 100-in reflector in California (1917), he discovered the spiral structure of the nebula Messier 51 near the tail of the Great Bear (1845), the first ever observation of a spiral galaxy. Drawings of this and of many other nebulae, including spirals, were published in Rosse's catalogue of nebulae (1850). His giant mirror is preserved in the Science Museum, London.