The 1st Earl of Rosse, William Parsons, was an Irish nobleman born in 1800. He is best known for his contributions to astronomy, particularly through the construction of the Leviathan of Parsonstown, a large telescope that was the world's largest in the 19th century. This telescope allowed for significant advancements in the study of celestial bodies. In addition to his work in astronomy, the 1st Earl of Rosse was also involved in various scientific endeavors and was a member of the Royal Society. He played a key role in promoting scientific research in Ireland and was recognized for his contributions to both science and society until his death in 1867.