Great Rose Telescope, Birr Castle, Parsonstown, Ireland, c 1880.

Photograph by Colonel Harry J Watson showing the Great Rose Telescope from the southeast. Constructed between 1842 and 1845 by William Parsons, Third Earl of Rose (1800-1867), the telescope soon became known as the 'Leviathan of Parsonstown'. Located in Ireland at Parsonstown, now Birr, the reflecting telescope had a 6 foot metal mirror weighing four tons. Rose used his great instrument to try and determine the nature of nebulae - misty patches in the sky. It was mounted in a 15m tube slung by chains between masive masonry walls. This image is one of two photographs taken of the telescope by Colonel Harry J Watson, who as a serving officer was posted to barracks at the nearby town of Newbridge.