The Monster Telescopes, Erected by the Earl of Rosse, Parsonstown - 1845
The William Parsons, Third Earl of Rosse, built a 72 inch diameter telescope in 1845 that was the largest telescope until the early 20th century. The telescope was built and erected on the grounds of Birr Castle, located in Parsonstown, Ireland. Using the 72 inch telescope, also known as the Leviathan of Parsonstown, William Parsons first observed the spiral structure of M51 (Whirlpool Galaxy). This book describes the construction of his 36 inch and 72 inch telescopes. There are two albumen photographs of the 72 inch telescope pasted to the rear flyleaf and pastedown. See my other book "Observations of the Nebulae", which is a report of his observations of nebulae using the 72 inch telescope.