Lord Rosse (William Parsons) (1800 – 1867)

Fig 1: Lord Rosse (William Parsons) (1800 – 1867)

The art and science of astronomy was still a novice subject and rising field in the 19th century. We do not find a lot of professional astronomers at that time. It was then studied mostly by the amateur astronomers though with full passions. Lord Ross (William Parsons) was one of the greatest amateurs full of passion of that century who finally became not only a prominent astronomer but also a naturalist and engineer. 

Lord Rosse was the third Earl, born in England. He graduated in mathematics with an outstanding result in 1822. He inherited an estate including a castle in Ireland from his father, the second earl after his death. He was then fully devoted to astronomy and trying to make telescopes. In 1845, he completed making the telescope named  ‘Leviathan of Parsonstown’ which was the largest telescope of that century having a length of 72 inches (6 feet/1.83 m). Previously he made a telescope that was 36 inches (910 mm) long.

Fig 2: The 72-inch telescope at Birr Castle (The Leviathan of Parsonstown)

This telescope was considered a revolutionary technical and architectural achievement. It was the world’s largest telescope according to the aperture size at that time. Rosse could see and catalog so many nebulae using this telescope. However,  This telescope had a 72-inch metal mirror in it. There were two walls on the two sides of it which made it one-directional. The telescope was huge and that is why it was not comfortable for regular use. He often used his 36-inch telescope for which he made two speculum metal mirrors. As this metal mirror was tarnished after some days and needed polishing, he could use the polished one while the other one was being polished.

This Leviathan telescope is now preserved in the castle he inherited which is now used as a national landmark and museum. If you want to visit there, you can get more information on their official website: Official Birr Castle Website 

Contributions on Astronomy

His biggest contribution was making the telescopes and extraordinary drawings of the celestial bodies. With his telescopes, he could observe many celestial bodies that were not seen before. He found the spiral nature of what we know today as spiral galaxies. His telescope first discovered the spiral structure of the Whirlpool Galaxy (M51). His drawing on this almost resembles the recent photographs.

Fig 3: Lord Rosse’s drawing of M51, Whirlpool Galaxy. 

This was the first spiral galaxy where he could resolve what the spiral arms were.

Fig 4: Lord Rosse’s drawing of M1 the Crab Nebula

 He named the Crab nebula as he found that his drawing of the nebula looked like a crab. He observed this through his 36-inch telescope.

This is a drawing of M1 the Crab Nebula. You can see how it got its name! He made this drawing with a 36-inch reflector. He described that it looked like a cluster, but there was a considerable change in the look.

Fig 5: Lord Rosse’s drawing of M97 (the Owl Nebula)

About the Owl Nebula, he told in his report that there were two stars at the center, and the outer regions were partially shaded and dark around each spiral arm. He also attempted to analyze the nebular hypothesis.