William Parsons, 3rd Earl of Rosse

William Parsons, 3rd Earl of Rosse, was an English engineer and astronomer. He built several giant telescopes. His 72-inch telescope, built in 1845 and colloquially known as the "Leviathan of Parsonstown", was the world's largest telescope, in terms of aperture size, until the early 20th century. From April 1807 until February 1841, he was styled as Baron Oxmantown.