Reverend William Frederick Archdall Ellison FRAS, Irish clergyman, Hebrew scholar, organist, avid amateur telescope maker, and, from 1918 to 1936, director of Armagh Observatory in Armagh, Northern Ireland, is born on April 28, 1864. He is the father of Mervyn A. Ellison, the senior professor of the School of Cosmic Physics at Dunsink Observatory from 1958 to 1963.
Ellison comes from a clerical family, his father Humphrey Eakins Ellison having been Dean of Ferns, County Wexford. He gains a sizarship of classics at Trinity College, Dublin in 1883, becomes a Scholar of the House in 1886 and graduates in 1887 with junior moderatorships in classics and experimental science. In 1890 he takes Holy Orders and moves to England, where he becomes the Curate of Tudhoe and Monkwearmouth. In 1894 he takes his MA and BD degrees and in the following year wins the Elrington Theological Prize.
In 1899 he returns to Ireland to become secretary of the Sunday School Society, a post which he holds for three years before accepting the incumbency of Monart, Enniscorthy, moving in 1908 to become Rector of Fethard-on-Sea with Tintern in Wexford. Ellison develops an interest in astronomy, having been introduced to practical optics by Dr. N. Alcock of Dublin and sets up his first observatory at Wexford. He becomes highly adept at making lenses and mirrors and writes several books and articles on the subject, including major contributions to the Amateur Telescope Making series, the Journal of the British Astronomical Association, and the weekly newspaper The English Mechanic. His book The Amateur’s Telescope (1920) is still considered a standard for telescope-makers and a forerunner of the more extensive series on the same topic by Albert Graham Ingalls.
On September 2, 1918 Ellison is appointed Director of the Armagh Observatory. He finds the Observatory in a state of disrepair and sets about repairing the instruments and the observatory dome. On January 3, 1919 he deeds a telescope of his own to the observatory, an 18-inch reflecting telescope, which is still there.
Ellison is a highly regarded planetary and binary star observer. Working with his son Mervyn, he makes many measurements of binary stars using the observatory’s 10-inch Grubb refracting telescope and even discovers a new one close to Beta Lyrae, and according to Patrick Moore, is one of the few people to have observed an eclipse of Saturn’s moon Iapetus by Saturn’s outermost ring on February 28, 1919.