Great Rosse Telescope, 1842-1845

Great Rosse Telescope, 1842-1845. This scale model (1:24) of the Great Rosse Telescope was made prior to its construction in 1842-1845, as it includes an observing platform that was never built. Constructed in Ireland by William Parsons, Third Earl of Rosse (1800-1867), it was soon known as the 'Leviathan of Parsonstown'. The reflecting telescope used a 6-foot metal mirror weighing four tons. This was mounted in a 15 m tube slung by chains between massive masonry walls. Rosse used his great instrument to try and determine the nature of nebulae, misty patches in the sky. He was the first to discover that some had spiral forms. They are now known to be galaxies, remote and massive islands of stars like our own Milky Way. ©SSPL/Science Museum