Downing, Arthur Matthew Weld

(b. Carlow, Ireland, 13 April 1850; d. London, England, 8 December 1917)

astronomy.

Downing’s chief contribution was the computation of precise positions and movements of astronomical bodies; he was also one of the founders of the British Astronomical Association. The younger son of Arthur Matthew Downing, Esq., of County Carlow, he received his early education under Philip Jones at the Nutgrove School, near Rathfarnham, County Dublin. He thence proceeded in 1866 to Trinity College, Dublin, where he obtained the scholarship in science and graduated B.A. in 1871, gaining the gold medal of his year in mathematics. He took his M.A. degree in 1881, and in 1893 Dublin University granted him the honorary degree of D.Sc.

In 1872 Downing was appointed assistant at the Royal Observatory, Greenwich, to commence 17 January 1873. There he was placed in charge successively of the library and manuscripts, the time department, and the circle computations. Reduction of the circle, altazimuth, and equatorial observations came to constitute his major responsibility, but he also served as one of four regular observers with the transit circle and altazimuth. Following his election as fellow of the Royal Astronomical Society in 1875, he communicated seventy-five papers to the society, dealing principally with the correction of systematic errors in different star catalogs and with the computation of fundamental motions of the heavenly bodies. Among the papers is a calculation done in collaboration with G. Johnstone Stoney of perturbations suffered by the Leonid meteors, which predicted and explained the relative sparseness of the 1899 shower.

Downing’s next appointment, as superintendent of the Nautical Almanac Office, extended from 1 January 1892 to his statutory retirement on 13 April 1910. During this period he brought out the Nautical Almanac for the years 1896 to 1912, gradually instituting various improvements therein, including increasing the number of ephemeris stars, introducing Besselian coordinates into the eclipse and occultation lists, and expanding the sections on planetary satellites. He also replaced the solar and planetary tables of Le Verrier with those of Simon Newcomb and George Hill, dropped the obsolete Lunar Distance Tables, and introduced into the Almanac the physical ephemerides of the sun, moon, and planets.

As one of the founders in 1890 of the British Astronomical Association and subsequent nurturer of its early development, Downing contributed significantly to amateur astronomy. His consistent advance publication of particulars of astronomical occurrences, such as eclipses and occultations, constituted a valuable service to observers in many countries.

In 1896 Downing was elected fellow of the Royal Society and officiated in Paris at the important International Conference of Directors of Ephemerides, which sought to attain uniformity in the adoption of astronomical constants. In 1899 he revised Ernst Becker’s Tafeln zur Berechnung der Precession, adapting them to a new value of the precessional constant first derived by Simon Newcomb in response to a formal request presented to him at the Paris meeting. The epoch adopted for the tables was 1910, but they were constructed to be useful for at least ten years before and after that year. In 1901 Downing compiled a revised version of Taylor’s Madras Catalogue of 11,000 stars, reduced without proper motion to the equinox of 1835. His sudden death in 1917, following several years of illness, was from a recurrent heart complaint.

Downing was secretary (1889–1892) and vicepresident (1893–1895) of the Royal Astronomical Society, as well as vice-president (1890–1891) and second president (1892–1894) of the British Astronomical Association.

BIBLIOGRAPHY

I. Original Works. Seventy-five papers communicated to the Royal Astronomical Society are listed in the General Index to the Monthly Notices of the Royal Astronomical Society covering vols. 1–52 (1870) and vols. 53–70 (1911). See especially the Downing-Stoney paper “Ephemerides of Two Situations in the Leonid Stream,” in Monthly Notices of the Royal Astronomical Society.59 (1898), 539–541. Other joint communications with Stoney on this subject include “Perturbations of the Leonids,” in Proceedings of the Royal Society, 64A (1899), 403–409; and two letters to the editor of Nature: “Next Week’s Leonid Shower,” 61 (1899), 28–29, and “The Leonids—a Forecast,” 63 (1900), 6. Another paper, by Downing alone, concerning meteors is “The Perturbations of the Bielid Meteors,” in Proceedings of the Royal Society, 76A (1905), 266–270. A report by Downing to the British Astronomical Association on 28 June 1905, concerning his researches on the Bielids, is described in Journal of the British Astronomical Association, 15 , no. 9 (1905), 361–363.

Nineteen contributions to Observatory (of which Downing was editor of vols. 8–10 [1885–1887]) are in vols. 2–4, 6, 8, 12, 27, 30, 33, 36 and 39 . A determination of the sun’s mean equatorial horizontal parallax is in 3 , no. 31 (1879), 189–190. See also Astronomische Nachrichten, 96 , no. 2288 (1880), 119–128.

Twenty-one contributions to the Journal of the British Astronomical Association are in vols. 1,3, 8, 10, 15–19 , and 21–22 . Besides accounts of observational phenomena these include “How to Find Easter,” 3 , no. 6 (1893), 264–268; and “When the Day Changes,” 10 , no. 4 (1900), 176–178, the latter trans. as “Où le jour change-t-il,” in Ciel et terre, 21 (1900), 84–86. Downing edited the first of the eclipse volumes of the British Astronomical Association dealing with the eclipse of 1896 (he also organized an Association expedition that failed to observe the eclipse because of cloud). He issued in addition several Association circulars giving advance particulars of other current notable eclipses. He was private adviser over many years to the editor of the Journal of the British Astronomical Association (see acknowledgment by A. S. D. Maunder, 28 , no. 2 [1917], 67–69).

Ten letters to the editor of Nature, two in conjunction with Stoney, see above, are in vols. 17, 59, 61, 63, 65, 71–72, 76, 78 , and 90 . The receipt of advance particulars of various astronomical phenomena from Downing is frequently noted and quoted in the editorial columns of this journal. While superintendent of the Nautical Almanac Office, Downing compiled for the years 1896–1912 the Nautical Almanac and Astronomical Ephemeris for the Meridian of the Royal Observatory at Greenwich (for 1896–1901, published London, 1892–1897; for 1902–1912, published Edinburgh, 1898–1909). See seven-page appendix to the Nautical Almanac for 1900, which contains a continuation of tables I and III of Damoiseau’s Tables of Jupiter’s Satellites for the Years 1900–1910.

Other contributions are his revision of Becker’s Tafeln... Precession: Precession Tables Adopted to Newcomb’s Value of the Precessional Constant and Reduced to the Epoch 1910 (Edinburgh, 1899); and his revision of Taylor’s General Catalogue of Stars for the Equinox 1835.0 From Observations Made at the Madras Observatory During the Years 1831 to 1842 (Edinburgh, 1901).

II. Secondary Literature. Obituaries are A. C. D. Crommelin, in Nature, 100 (1917), 308–309; and A. S. D. Maunder, in Journal of the British Astronomical Association, 28 , no. 2 (1917), 67–69. Unsigned obituaries are in Observatory, 41 , no. 522 (1918), 70; and Monthly Notices of the Royal Astronomical Society, 78 , no. 4 (1918), 241–244. References to his role in founding the British Astronomical Association are made by Howard L. Kelly in Memoirs of the British Astronomical Association, 36 , pt. 2 (1948), a Historical Section memoir. Summaries of some of Downing’s original papers in Journal of the British AstronomicalAssociation, Monthly Notices of the Royal Astronomical Society, and Proceedings of the Royal Society appear in the editor’s column of contemporary issues of Nature.

Susan M. P. McKenna