Lord Rosse's Birr telescopes. These are the 3-foot telescope (right) and the 6-foot telescope (the Leviathan of Birr, left), at Birr Castle, Parsonstown, Ireland. These telescopes were constructed in 1839 and 1845 respectively by the Irish astronomer William Parsons (1800-1867), the 3rd Earl of Rosse. Pioneering research carried out with these telescopes include the meaasurements with the 3-foot telescope of the temperature of the Moon (1868), and observations with the 6-foot telescope of the spiral structure of the M51 galaxy (1845). The 3-foot telescope is being operated by the man in the basket. The 6-foot telescope is accessed by ladders and reinforced by walls.