A beautiful spiral galaxy spins into view in the northeast this evening, near the tip of the Big Dipper’s handle. It actually consists of two galaxies: a large one that’s interacting with a smaller one, with a “bridge” of stars and gas between them.
M51 is the first galaxy whose spiral nature was seen. It was revealed by the Leviathan of Parsonstown — the largest telescope in the world at the time. It entered service in 1847 — 175 years ago.
The Leviathan was the invention of William Parsons, the Earl of Rosse, in Ireland. He owned and operated a large estate, but was also interested in astronomy. And he designed a telescope that far outclassed anything else of the time.
Its main mirror spanned six feet — two feet wider than the second-largest. The metal mirror had to be taken out and polished every six months, so Parsons made two of them. The mirrors fit into a tube that was 58 feet long. It was suspended between two brick walls, and assistants used cables and pulleys to move it.
Parsons did some of the observing himself, but he also hired a professional. Together, they studied the odd, fuzzy objects known as nebulae. Astronomers hadn’t figured out what they were. The Leviathan revealed that some are clusters of stars. But more than a hundred were spirals. Decades later, astronomers showed that these objects are separate galaxies of stars — beautiful spirals first resolved with the Leviathan of Parsonstown.
Script by Damond Benningfield