Rosse, William Parsons

Rosse, William Parsons, third EARL OF, an astronomer, was born in York on 17th June 1800, and educated at Trinity College, Dublin, and Magdalen College, Oxford, where he graduated first-class in Mathematics in 1822. During the life of his father he sat in the House of Commons as Lord Oxmantown, representing King's County from 1821 to 1834; he succeeded to the peerage in 1841, and was elected a representative peer for Ireland in 1845. As early as 1826 he had commenced to make experiments in the construction of fluid lenses; but he subsequently devoted his powers to the construction of a speculum for the reflecting telescope. Certain defects had hitherto baffled opticians—namely, spherical aberration and absorption of light by specula, and in casting specula of large size cracking and warping of the surface on cooling; but Lord Rosse succeeded in obviating the last defect, and in counteracting in great part the other two. He began the construction of his great reflecting telescope in 1845; it weighed in all 12 tons, and was mounted in his park at Parsonstown at a cost of £30,000. The first addition to astronomical knowledge made by this telescope was the resolution of certain nebulae into groups of stars; next came the discovery of numerous binary and trinary stars, and a description of the moon's surface. The telescope is described in the Philosophical Transactions, in which journal, and in the Transactions of the Royal Society, Dublin, most of his papers were published. Lord Rosse was president of the Royal Society from 1848 to 1854. He died on 31st October 1867, and a statue to his memory was erected in Parsonstown in 1876.