Australian Dictionary of Biography

James Dunlop (1793-1848), by Joseph Backler, c1843

State Library of New South Wales, Original : ML 705

James Dunlop (1793-1848), astronomer, was born on 31 October 1793 at Dalry, Ayrshire, Scotland, the son of John Dunlop, weaver, and his wife Janet, née Boyle. After primary level his education was at night-school in Beith where he worked in a thread factory. He was constructing telescopes at 17, and some ten years later an acquaintance with Sir Thomas Brisbane developed his interest in astronomy. When appointed governor of New South Wales, Brisbane resolved to establish an observatory, and chose Dunlop and Carl Rümker as assistants. They arrived in Sydney on 7 November 1821 and the instruments were set up in Parramatta in time to observe the solstice. A building was erected and regular observations began in May 1822. Apart from making the greater part of the observations for a catalogue of stars, Dunlop made observations of the length of the pendulum, the results of which were published with those of Captain Henry Kater in Philosophical Transactions of the Royal Society, 1823. In June 1822 Dunlop was the first to see the reappearance of Encke's comet. This was only the second case of the predicted return of a comet being verified, the first being that of Halley in 1758.

From June 1823, when Rümker left the observatory, to February 1827 was a busy period for Dunlop: he made about 40,000 observations which form the basis of the Parramatta Catalogue of Stars and, with an instrument built by himself, made the observations for his catalogues of nebulae and star clusters, and double stars. He then returned to Scotland to work in Brisbane's private observatory at Makerstoun in Roxburgh.

In 1831 Dunlop was appointed superintendent of Parramatta Observatory, which had been taken over by the government. He found the equipment and buildings of the observatory in bad condition, and had to exert much effort to restore them. In the period to 1835 he reported observations of asteroids, planets and comets in Memoirs of the Royal Astronomical Society. He made many transit observations, particularly with the new transit circle by Jones which he installed in 1835. He gave help and advice to Major (Sir) Thomas Mitchell when he was preparing his expeditions in 1831 and 1834. However, from about 1837 Dunlop appears to have been in ill health, his activity declined and the transit work done from 1832 at Parramatta was never reduced or published. He resigned and retired to his farm on Brisbane Water in August 1847 and died on 22 September 1848. His wife, Jean Service, whom he married in 1816, survived him for eleven years. They had no children.

Dunlop is now most often remembered for his work on the Catalogue of 7385 Stars from Observations Made at the Observatory at Parramatta, prepared by William Richardson of the Royal Observatory at Greenwich from the observations made in 1822-26, for his catalogue of 621 nebulae, published in Philosophical Transactions in 1828, and for his list of double stars, published in Memoirs of the Royal Astronomical Society in 1829. Because of the character of the instruments at Parramatta, the right ascensions in the catalogue of stars were of poor quality, but the declinations were better; with a view to their possible use for determining stellar motions, a new reduction of these was made by van Steenwijk and published in 1923. The designations in Dunlop's catalogues still apply to some of the star clusters and double stars.

Dunlop's interest ranged widely and included poetry, geology and zoology. Collections of birds, eggs, spears and the like gathered by him in Australia were in a museum near his native Dalry. The magnetic observations made from the 'beginning to the end of the voyage' to Australia in 1831 show his eagerness at that time to avoid inactivity. He was of hospitable disposition and showed kindness in cases of distress both among his neighbours at Parramatta and among Aboriginals near his farm. Dunlop was honoured in 1828 by the award of the gold medal of the Royal Astronomical Society for his catalogues of stars and nebulae.