Johnson, Manuel John

(b. Macao, China, 23 May 1805; d. Oxford, England, 28 February 1859)

astronomy.

While stationed on the island of St. Helena, Johnson measured the positions of southern hemisphere sphere stars and compiled a catalogue of them. Later, while serving as Radcliffe observer at Oxford, he made a catalogue of northern hemisphere stars as well

His father was an Englishman named John William Johnson. As a boy, Manuel attended Addiscombe College, a military school located near Croydon, just south of London, where cadets were prepared for service in the British East India Company. At age sixteen, with the rank of lieutenant, he was assigned to an artillery division stationed on St. Helena.

With time on his hands at this isolated place, Johnson began to study the heavens. He was encouraged in this pursuit by the governor of St. Helena, General Alexander Walker, to whom he had been assigned as aide-de-camp. Funds to build and equip an observatory were provided by the East India Company; and Johnson was sent twice to Cape Town, in 1825 and again in 1829, to get advice from Fearon Fallows, then royal astronomer at the recently established Cape of Good Hope observatory.

The observatory on St. Helena was completed in 1829. During the next four years Johnson made the observations that formed the basis of his Catalogue of 606 Principal Fixed Stars of the Southern Hemisphere, published in 1835 at the expense of the East India Company.

St. Helena was returned to the British crown in 1834, The artillery unit was disbanded, and Johnson returned to England on a pension. In February 1835 he was awarded the gold medal of the Royal Astronomical Society for his star catalogue, and in December of that same year he enrolled as an undergraduate in Magdalen College, Oxford. He graduated B. A. in 1839 and M. A. in 1842

When the Radcliffe observer, Stephen Peter Rigaud, died early in 1839, Johnson applied for the position and obtained it; in October 1839 he took up residence in the Radcliffe Observatory (then in the northwest suburbs of Oxford but transferred about a century later to Pretoria, South Africa). He remained there until his death twenty years later.

As Radcliffe observer, Johnson, with the initial help of Sir Robert Peel (one of the Radcliffe trustees), reequipped the observatory, buying telescopes and a heliometer, and—starting out only to revise Groombridge’s catalogue—assembled material for his Radcliffe Catalogue of 6317 Stars, Chiefly Circumpolar.He also continued the meteorological observations begun by Rigaud and made many differential measurements with the heliometer.

In 1850 Johnson married Caroline Ogle. He was elected to fellowship in the Royal Society in 1856 and served as president of the Royal Astronomical Society in 1856- 1857. His death followed a period of declining health because of heart disease.

BIBLIOGRAPHY

I. Original Works. Johnson’s writings include A Catalogue of 606 Principal Fixed Stars in the Southern Hemisphere; Deduced From Observations Made at the Observatory, St. Helena, From November 1829 to April 1833 (London, 1935) and Astronomical Observations Made at the Radcliffe Observatory; Oxford, I- XIX (Oxford, 1842- 1861) mdash; with vol. XIV the title was changed to Astronomical and Meteorological Observations. . . and in that volume is a summary of the meteorological records kept at the Radcliffe Observatory for twenty- five years, extending back into Rigaud’s tenure. Johnson’s northern hemisphere star observations appeared as The Radcliffe Catalogue of 6317 Stars, Chiefly Circumpolar; Reduced to the Epoch 1845.0; Formed From the Observations Made at the Radcliffe Observatory, Under the Superintendence of Manuel John Johnson, M. A. Late Radcliffe Observer (Oxford, 1860); this was complete and in the hands of the printer before Johnson died.

In addition, Johnson published thirteen papers, listed in the Royal Society’s Catalogue of Scientific Papers, III (London, 1869), 556- 557; one of these was written with Norman Pogson as junior author (Pogson, who devised the scale of stellar magnitudes still in use today, served as Johnson’s assistant for some years, beginning in 1851)

II. Secondary Literature. Johnson’s certificates of marriage (16 July 1850) and death are in the General Register office, London. Francis Baily’s citation when he presented Johnson the gold medal of the Royal Astronomical Society appeared in Memoirs of the Royal Astronomical Society, 8 (1835), 298- 301. Other contemporary accounts of Johnson’s life and accomplishments can be found in the (London) Times (2 Mar. 1859, p. 5, col. 6), and (4 Mar. 1859, p. 5, col. 1); Monthly Notices of the Royal Astronomical Society, 20 (1860), 123- 130; and Proceedings of the Royal Society, 10 (1860), xxi- xxiv.

Later sources include C. André and G. Rayet. L’ astronomie pratique, I (Pairs, 1874), 57- 60; Agnes Mary Clerke, in Dictionary of National Biography, XXX (London, 1892), 22- 23; and Joseph Foster, Alumni Oxoniensis, 1715- 1886 (Oxford, 1888), II, 757, col. 2.

Sally H. Dieke