Christie, William Henry Mahoney

(b. Woolwich, England, 1 October 1845; d. at sea, 22 January 1922). asronomy.

Christie was perhaps more important in the administration of astronomy than in advancing the theoretical foundations of the subject. Under his care, the observatory at Greenwich prospered more materially than it had done at any time since its foundation in 1675.

W. H. M. Christie was the eldest son of S. H. Christie, a professor of mathematics at the Royal Military Academy, Woolwich, and secretary to the Royal Society (1837–1854). The famous London firm of auctioneers was founded by Christie’s grandfather. William was educated at King’s College, London, and Trinity College, Cambridge, where he was fourth wrangler in 1868. He was elected a fellow of his college in 1869, but a year later he left Cambridge to become chief assistant at the Royal Observatory at Greenwich. There he was engaged primarily in positional astronomy, and one of his early minor achievements was to improve Airy’s transit circle in several respects.

Despite Airy’s influence over him, Christie was anxious that Greenwich should undertake physical as well as positional observations, and with the help of E. W. Maunder he undertook daily sunspot observations (correlating them in due course with terrestrial magnetic observations) and also made many attempts, although not highly successful ones, to measure the radial velocities of stars. He made and reported many planetary observations, as, for example, that of the Mercury halo during the transit of 6 May 1878, and made many eclipse expeditions, often bringing back very fine photographic records. Nevertheless, Christie made no remarkable advances outside the realm of “fundamental” astronomy.

Work on this subject, which had been the prime justification for the foundation of the observatory, necessarily for the foundation of the observatory, necessarily continued as before, after Christie was made astronomer royal in 1881, but it is to his credit, and that of the Admiralty, that the scope of observations during this period went far beyond utilitarian needs. Christie equipped the observatory with many new instruments, notably a twenty-eight-inch visual refracting telescope (completed 1894), and a twenty-six-inch photographic refractor with a twelve-and-three-fourth-inch guiding telescope. This had a nine-inch photoheliograph on the same mounting (the gift of the surgeon Sir Henry Thompson in 1894) and enabled Greenwich to participate in the international photographic survey. He added several new buildings to the existing range, and moved the magnetic pavilion to an isolated building in Greenwich Park. With the twenty-eight-inch refractor, Christie initiated a large program for the micrometric observation of double stars.

Christie was elected a fellow of the Royal Society in 1881 and was president of the Royal Astronomical Society from 1890 to 1892. Among his other honors he was created C.B. in 1897 and K. C. B. in 1904. In 1910 he retired to Downe, in Kent. His wife (Violet Mary Hickman) died in 1888, after only seven years of marriage, and one son survived him. Christie himself died at sea on a voyage to Mogador, Morocco, in 1922.

BIBLIOGRAPHY

I. Original Works. More than a dozen volumes of astronomical and other observations were published by Christie, or under his direction, under the auspices of the Greenwich Observatory. His most substantial work was the six-volume Astrographic Catalogue for 1900.0 (Greenwich section, 1904–1932), completed after his death. Other works of interest are Telegraphic Determinations of Longitude Made in the Years 1888–1902 Under the Direction of Sir W. H. M. Christie (Edinburgh, 1906); and Temperature of the Air as Determined From the Observations and Records of the Fifty Years 1841 to 1890, Made at the Royal Observatory, Greenwich, Under the Direction of W. H. M. Christie (London, 1895), with a second volume for 1891–1905 (London, 1906). Other volumes concern photographic records of the barometer and thermometer, photoheliographic results, observations of the minor planet Eros, and a reduction of Groombridge’s circumpolar catalogue for 1810.0.

II. Secondary Literature. Apart from an entry by F. W. Dyson in the Dictionary of National Biography (vol. for 1922–1930), the main source of information remains the numerous obituary notices of Christie. For information concerning his innovations at Greenwich, see the numerous editions of the descriptive handbooks issued by the observatory (published by Her Majesty’s Stationery Office) and E. W. Maunder’s The Royal Observatory Greenwich (London, 1900), with contemporary photographs of many of the buildings.

John North