William Parsons, the 3rd Earl of Rosse was both an English engineer and astronomer. He is famous for building the Leviathan of Parsonstown, in his effort to determine if the nebulae in Charles Messier's and Sir John Herschel's catalogs were unresolved star clusters or galaxies of their own. He sketched Messier 51 giving to us it's spiral structure and resolved stars in that nebuale forever changing astronomers view of the cosmos above.
The full article on Sir William Parsons 3rd Earl of Rosse and his mighty Leviathan of Parsonstown telescope is available over at Eadsy Astronomy.
