17 June 1800: The Birth of the future  3rd Earl of Rosse on this day. He was born at York in northern England. He went to Oxford and graduated in 1822 with a 1st Class Degree in Mathematics. He inherited an Earldom and a large Estate in County Offaly in 1841 upon the death of his father.

He was the most prominent astronomer of his time and built the world’s largest and most powerful telescope of the age on his estates at Birr Castle, County Offaly. He first represented  the Kings County at Westminister as Lord Oxmanstown but was indifferent to deep political considerations. In politics he was a moderate conservative but of an independent mind on some leading questions.

After retiring from the world of politics he applied himself to the pursuit of astronomical science. Starting almost from scratch he assembled a series of large telescopes that he perfected through trial and error till eventually he produced his magnificent 72 inch optical reflector telescope– the ‘Leviathan of Parsonstown’.

With this he discovered or developed  many unknown or little understood heavenly objects including the remains of the burnt out star Supernova SN 1054. He observed that nebula at Birr Castle in the 1840s, and referred to the object as the ‘Crab Nebula’ because a drawing he made of it that looked like a crab, which is still the name it is most commonly known as to this day.


One of Rosse's telescope admirers was Thomas Langlois Lefroy, a fellow Irish MP, who said:

 The planet Jupiter, which through an ordinary glass is no larger than a good star, is seen twice as large as the moon appears to the naked eye/.../But the genius displayed in all the contrivances for wielding this mighty monster even surpasses the design and execution of it. The telescope weighs sixteen tons, and yet Lord Rosse raised it single-handed off its resting place, and two men with ease raised it to any height.

In 1849 he was elected President of the Royal Society. He was elected a member of the Imperial Acadamy at St Petersburg, and created a knight of the Legion of Honour by Napoleon III. He also received the Knighthood of St Patrick from Queen Victoria. Though born in England to an Anglo-Irish family he was strongly attached to this country by the ties of family, property and sympathy.

In addition to his astronomical interests, Rosse served as an Member of Parliament (MP) for King's County from 1821 to 1834, an Irish representative peer after 1845, president of the Royal Society (1848–1854), and chancellor of Trinity College, Dublin (1862–1867).