Lord Rosse's 3-foot telescope, at Birr Castle, Parsonstown, Ireland. This telescope was constructed in 1839 by the Irish astronomer William Parsons (1800-1867), later the 3rd Earl of Rosse. Pioneering research carried out with this telescope includes the 4th Earl's measurements of the temperature of the Moon in 1868. The more famous telescope is the 6-foot Leviathan of Birr, used to observe nebulae (later called galaxies). The 3-foot telescope was originally operated using an altazimuth mount. In the 1870s it was mounted equatorially. The basket at left was used to raise the observer to the top of the telescope and make observations by looking down the telescope's framework barrel at the mirror.