Wilson, William Edward (1851–1908), astronomer, was born 19 July 1851 at Greenisland, near Carrickfergus, Co. Antrim, the only son of John Wilson (d. 1906), landowner, of Daramona House, Streete, Co. Westmeath, and his wife Francis Patience, daughter of the Rev. Edward Nangle (qv); he had three younger sisters. His father had an interest in philosophy and published Thoughts on science, theology and ethics (1885). A delicate child, William was educated privately at home and, with the encouragement of his father, developed an interest in astronomy at an early age. At the age of nineteen he took part in an unsuccessful expedition in 1870 to observe a total solar eclipse in Algeria. The following year he set up an observatory equipped with a 12-in. (30 cm) Grubb reflecting telescope in the garden at Daramona. With this instrument he experimented with photography of the moon, using wet plates, and began his study of solar radiation using thermopiles. In 1881 he bought a 24-in. (60 cm) mirror and tube from Howard Grubb (qv) and installed them in a new dome, which adjoined Daramona House.
His astronomical career was concerned with three main subjects: the electrical measurement of the brightness of the stars, the determination of the temperature of the solar photosphere, and celestial photography. In December 1893 he met G. M. Minchin (qv) in London, who persuaded him to test his selenium cells for the electrical detection of starlight at the Daramona observatory. The first recorded observations at Daramona were taken in April 1895 with the help of Minchin and George Francis Fitzgerald (qv). A second set of observations at the same location were taken the following year (January 1896). Between 1892 and 1897 Wilson also carried out a series of observations in collaboration with P. L. Gray of Mason College, Birmingham, and Arthur Rambaut (qv) of Dunsink observatory, using a heliostat and a sensitive detector to estimate the temperature of the sun. A first estimate of 7073°K was published in 1894 (‘Experimental investigations on the effective temperature of the sun’, Philosophical Transactions of the Royal Society (1894), 361–96). After a revised calculation taking into account the absorption of the Earth's atmosphere as well as the solar atmosphere, the value was corrected in 1901 to 6590°K (‘The effective temperature of the sun’, Proceedings of the Royal Society (1901–2), 312–20), which was the first accurate determination of the temperature of the solar photosphere. His final value compares fairly well with modern estimates (e.g. around 5780°K). From 1893 the 24-in. telescope was used for photographing nebulae and star clusters. Photographs of the solar disc were regularly taken using a 4-in. (10 cm) Grubb lens for studying sunspots, and Wilson's collected papers were published privately as Astronomical and physical researches made at Mr Wilson's observatory, Daramona, Westmeath (1900).
In May 1900 Wilson accompanied Howard Grubb and Charles Jasper Joly (qv) on an eclipse expedition to Plasencia in Spain jointly organised by the RIA and the RDS. He was elected MRIA (1888) and FRS (1896), and received an honorary doctorate from TCD (1901). He also served as high sheriff for Co. Westmeath in 1894. A sincere and earnest man, he had a quiet charm that evoked respect and regard from his many friends, whom he enjoyed entertaining at Daramona House. He died 6 March 1908 at Daramona, aged 56, and was buried in the family plot in the graveyard of the parish church in Streete, Co. Westmeath.
He married (1886) Caroline Ada, third daughter of Capt. R. C. Granville of Biarritz, France, and was survived by his wife, one son, and two daughters. In 1925 his 24-in. telescope was given to the University of London and was used at the observatory at Mill Hill, London, which was purpose-built to house it. It was used mainly for spectroscopic research until 1951, when it was used for the practical instruction of astronomy students, before being donated in 1974 to the Merseyside County Museum, Liverpool. The rest of his physical apparatus was bequeathed to TCD. Daramona House, once under threat from developers, was included in 2003 in the record of protected structures of Westmeath county council. The house was also the birthplace of Wilson's nephew, Kenneth E. Edgeworth (qv) whose prediction in 1943 of the existence of a source of cometary material beyond the orbit of Neptune was proved correct in 1992.