Leviathan of Parsonstown

The Leviathan of Parsonstown was a convert|72|in|m|sing=on reflecting telescope and the largest telescope in the world from 1845 until the construction of the convert|100|in|m|sing=on Hooker Telescope at Mount Wilson Observatory in 1917. The telescope was built by William Parsons, 3rd Earl of Rosse on his estate, Birr Castle, at Parsonstown (now called Birr) in Ireland. The convert|72|in|m|sing=on telescope accompanied a convert|36|in|mm|sing=on telescope at Birr Castle.

The telescope mirror was made from speculum metal. Because the mirror tarnished so rapidly in the damp climate, the mirror had to be repolished every six months. Lord Rosse had two mirrors built so that one could be used while the other was being repolished. The light-gathering ability exceeded expectations, enabling 18th magnitude stars to be observed for the first time. The telescope was also the first one able to detect the spiral structure of some galaxies. The Irish sky was not kind to astronomy, and due to weather conditions there were only about 60 good nights of viewing available per year.

The telescope fell into disuse, disrepair and rot. One of the convert|72|in|m|sing=on mirrors was taken to the Science Museum (London) in 1914 and the (rotten) wood was taken down for safety reasons in 1925. It has since been reassembled as a tourist attraction, though for insurance reasons, the general public cannot use the telescope.

External links

* [http://www.klima-luft.de/steinicke/ngcic/persons/rosse3.htm Several Victorian drawings and photos of the original telescope (and also its convert|36|in|mm|sing=on predecessor)]
* [http://www.birrcastle.com/telescopeConstruction.asp Website of today's Birr Castle includes a short history of construction of the telescope]
* [http://www.lawrencetown.com/birr.htm A fuller account of the of the telescope's decline in use, disrepair, and staged dismantling.]