1-158-186 - Oxford Science Archive/Heritage Images

Observation of a spiral galaxy in Canes Venatici drawn by Lord Rosse, 1850. Known as the Whirlpool Galaxy, this was the first galaxy to be recognised as having a spiral structure, by the British astronomer William Parsons, Lord Rosse in 1845. Rosse built a telescope at Birr Castle in Ireland between 1842 and 1844. Known as 'The Leviathan of Parsonstown', the Rosse telescope had a six foot speculum (mirror), and was the largest telescope in the world for 75 years, only being superseded by the 100-inch reflector at Mount Wilson, California in 1917. From Lord Rosse's paper Observations of Nebulae published in Philosophical Transactions, London, 1850.