In 1821, Sir Thomas Brisbane was appointed Governor of New South Wales. He arrived in November, and with the assistance of Carl Rumker and James Dunlop, established a private observatory near Government House in Parramatta. They began observations in 1822. (1) On 2 June 1822 Rumker rediscovered Enke's Comet.
When Brisbane left New South Wales at the end of 1825, the instruments were sold to the Government "not deeming it advisable to lose so favourable an opportunity as the acquisition of those Instruments afforded for promoting the Interests of Science in that Quarter of the Globe" (6) Rumker was appointed to take charge of the Observatory. He was selected by the Executive Council, 4 July 1826, to measure an arc of the meridian in New South Wales (7). In December 1827, Rumker was appointed Government Astronomer, the first to hold that title in Australia.(8) He was dismissed in 1829 (9) and was succeeded by James Dunlop, on 7 May, 1831.(10).
During Dunlop's appointment as Superintendent, the Observatory premises entered into a period of decay, to such an extent that Earl Grey wrote to Governor Fitzroy, 3 October 1846, requesting Dunlop to report immediately, and in future annually, on the work and condition of the Observatory. He also requested the establishment of a Commission to examine the Observatory each year 'in the same manner as is practised in the Royal Observatory.' (11)
The Commission, or Board of Visitors, was appointed in April 1847, consisting of Captain King RN, Lieut Colonel Gordon, Commanding Engineer and the Ordnance Storekeeper. In their report of the Observatory, 27 June 1847, they informed Fitzroy that the books and instruments were generally in good condition but the building itself was in a very dilapidated state. (12) On 3 June 1847, Earl Grey recommended that Dunlop’s services as Superintendent would be no longer needed after 31 March 1848 (13) . Due to his poor health Dunlop tendered his resignation to the Board with his first report on the Observatory 18 August 1847. (14)
Governor Fitzroy reported to Grey that no repairs short of rebuilding the premises could be made. Due to this expense, and the astronomer's resignation, he ordered the instruments to be packed away, for the sake of their preservation. (15) The Observatory closed some time after this despatch on 30 August, 1847 and the Government Observatory was not re-established until 1855 in Sydney.
A description of the Observatory and the original instruments may be found in HRA series 1, volume XI Note 137 p. 937
(1) HRA Series I Volume XI Note 137 p. 937 -938
(2) Ibid. Note 114 p. 932
(3) Ibid. p. 480
(4) Ibid p. 612
(5) HRA Series I Volume XII p580 -581
(6) Ibid. p 707 - 709
(7) HRA Series I v. XII Note 109, p. 829 .
(8) HRA Series I Vol XIII p.678 -679
(9) HRA Series I Vol XV p. 600
(10) Returns of the Colony, 1835 p. 138 (4/ 266)
(11) HRA Series 1 Vol .XXV p.213.
(12) Ibid. p. 657
(13) Ibid. p. 613 .
(14) Ibid. p. 733
(15) Ibid. P. 732
(1) "Concise Guide", 2nd Edition. "Sur - Y ", "Sydney Observatory " p.50.