The 3rd Earl is credited with the discovery of the spiral nature of galaxies by observing and drawing the Whirlpool Galaxy (M51), amongst others, using the giant 72 inch diameter reflector he had built in the grounds of Birr Castle, his ancestral home. Construction began in 1842 of the ‘Leviathan of Parsonstown’, as it came to be called. It was completed in 1845.

For 70 years it was the largest telescope in the world.

More information can be found at

https://en.wikipedia.org/wiki/William_Parsons,_3rd_Earl_of_Rosse

The SHA library have several books about William Parsons, the 3rd Earl of Rosse and his telescope in the library. Please contact the librarian for further details. The email address can be found by clicking here