Dr. Harold Corwin's Ireland Trip Photos of
Lord Rosse's "Leviathan" at Birr Castle
- September 9, 2020 -



Lord Rosse's 72-inch telescope on the grounds of Birr Castle with Harold Corwin in the foreground. The western part of the chain, pulley, and counterweight system for moving the telescope along the meridian is seen attached to the telescope and the west wall. The telescope became operational in 1845, but was not put into regular use until 1848 after the end of the potato famine that devastated Europe in the mid-1840s. Spiral structure in several nebulae was discovered almost immediately after observations began, and the telescope was primarily used over the next three decades for a survey of known nebulae in the northern hemisphere; several hundred new nebulae were discovered with it. Overall view of the 72-inch telescope with Kathleen Corwin in the foreground. The 1996-97 mechanical reconstruction is complete; the telescope and supporting structure closely resemble their appearance at the height of their use in the 1860s and 1870s, and are fully operational. A solid aluminum mirror was cast and polished in 1997-98 and was installed in the telescope during the summer of 1999. Regular observing began after a short testing period. Regular viewing with eyepieces and with CCD's will begin after a short testing period. One of the original speculum mirrors is on display in London; the other was lost by the time the original telescope was dismantled in 1908. Until the 100-inch telescope at Mt. Wilson in southern California began observations in 1917, Lord Rosse's 72-inch reflector was the largest telescope in the world.
Another view of the telescope.The observing platform raised to eyepiece level, with the telescope pointed east of the meridian. The telescope can follow a celestial object for about an hour as it crosses the meridian. The observing position normally used is at the Newtonian focus, but observing was occasionally done at a Herschelian focus at the front end of the tube. Manual controls for fine motion adjustments are attached to the tube.
The telescope being raised towards the zenith. The meridian radius on the eastern wall provides stability for the telescope at any altitude. The telescope pointed just south of the zenith -- lower portion. The lower end of the telescope rests on the original universal joint designed by the third Earl of Rosse and manufactured in the early 1840s. It, a few of the wooden slats in the telescope tube, and the eastern and western walls are the only parts remaining of the original telescope that could be incorporated into the reconstruction. The small hut seen against the east wall at the base of the telescope contains controls and motors that drive the telescope, though the manual controls and drive used in the 19th century can still be used if desired.
The telescope pointed just south of the zenith -- upper portion. Most of the meridian radius attached to the east wall is shown. The upper observing bridge can be moved towards the telescope, but is shown in its stored position on top of the west wall. All photos were taken on 9 Sept 1998.

For more information about Birr Castle, see http://www.birrcastle.com


All pictures scanned with a Hewlett-Packard 6200Cse,
36-bit, 1200 dpi, SCSI-2 based Scanner