The Leviathan of Parsonstown: That’s what the public named the telescope built in 1845 by Irish nobleman William Parsons, the third Earl of Rosse.
A leviathan is a giant sea monster. With a 72-inch metal mirror weighing 4 tons and a tube 54 feet long, it’s easy to see why people were so impressed by the reflector. The telescope was the high point of Lord Rosse’s astronomical adventures.
Rosse had decided that he wanted to build the world’s largest telescope. But to do that, he first needed to build the biggest mirrors. William Herschel hadn’t left behind any records of his mirror-making methods, so Rosse had to start almost from scratch.
Over 17 years, he managed to make a 15-inch (38-centimeter), 24-inch (61-centimeter) and finally a 36-inch-diameter (91-centimeter) mirror. Technology improvements, such as grinding tools powered by a small steam engine, meant he had an easier time crafting the mirrors than Herschel had experienced.
Rosse placed the 36-inch mirror in a Newtonian reflector. But he wasn’t satisfied yet. In 1842, he began to work on a 72-inch mirror. It took five tries before he created a mirror that could be used, and 3 years to build the actual telescope.
|Light collector:||Metal mirror|