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Table of Contents
Astronomical and Meteorological Workers in New South Wales
Admiral Phillip Parker King
Sir Thomas MacDougall Brisbane
Dr. Charles Stargard Rumker
P. E. De Strzelecki
Captain J. C. Wickham
Rev. W. B. Clarke, M.A.
Rev. A. Glennie
E. C. Close
Sir William Macarthur
S. H. Officer
William Stanley Jevons
Establishment of Meteorological Observatories
Votes and Proceedings, N.S.W., 1848.
We are told in the introduction to the Parramatta Catalogue "that James Dunlop was one of two gentlemen selected by Sir Thomas Brisbane to act as Astronomers in his observatory," and there is nothing said beyond this as to their relative rank; but from the fact that before starting Mr. Rumker was selected to take part with Sir Thomas in very important work, it seems probable that Rumker was first assistant and Dunlop second. From the time of his arrival in Sydney, Dunlop seems to have worked with a zeal and perseverance that not only justifies his selection, but made Sir Thomas speak more highly of him than he did Mr. Rumker, and set him to do specially difficult work, such as the observations of length of pendulum, &c. With Rumker, he observed regularly for the formation of the Catalogue. Both instruments, the transit and mural circle, were used for each star, the one for its right ascension and the other for its declination; and it is probable that one worked at each instrument, but it was soon found that the transit was very defective and gave such unsatisfactory results that it was worse than useless. We are not told when its use was given up; but we are informed (Introd. Parramatta Catalogue, p.7), that during the greater part of the time embraced by the Parramatta observations, Mr. Dunlop was the only observer; and, with a view to complete the observations for the formation of an extensive Catalogue he abandoned the Transit instrument, and fixing the Mural Circle as nearly in the plane of the meridian as he could, he commenced observing every star that circumstances permitted, as it passed the central wire registering the time of transit, and reading off as many microscopes as the interval, before another object came to the wire, would allow.
In the period of about two years and a-quarter he observed in this manner above 7,000 stars, and made nearly 40,000 observations, besides an extensive series of observations upon double stars and nebulae, an amount of labour which, perhaps, has never been performed before by any one within the same time. This change of instrument was made during the time Sir Thomas was there, and must have been with his consent, and it is very much to be regretted that it ever was made, as it would seem for the purpose of observing a great number of stars; because the Catalogue is practically useless, and its weakest point is the right ascension of the stars, and bad as the old transit instrument was, I know from working with it that it was capable of giving very much more accurate right ascension results than the mural circle, which has a short axis, and such a form of construction as to render accurate work in the meridian impossible; and there an, I think, be no doubt that the time mentioned, two and a-quarter years, is wrong, for the following reasons:Rumker left the Observatory 16th June, 1823, and Dunlop on March 2nd, 1826 (Introd Parramatta Catalogue), an interval of two years and eight months, and he says in a letter to Sir Thomas Brisbane (Royal Astronomical Society's Memoirs, VOL III., p. 257), that he stayed behind to follow out his favourite study, i.e., double stars and nebulæ, the meridian work in the Observatory having prevented him from doing so. He does not say how long he spent over this work, but it is evident from an extract which follows that he arrived in England in time to reduce most of these observations there, and have them ready to be presented to the Royal Society on 20th December, 1827. They did not require much reduction; probably a month would be time enough. Allow four months for the passage to England, and it would appear that he left Parramatta about the end of June, 1827, which would have given him sixteen months for nebulæ and double stars, and two years and eight months for meridian work, or, in all four years, not two and a-quarter years as stated.
A catalogue of six hundred and twenty-one nebulæ and clusters of stars observed at Parramatta by James Dunlop was presented to the Royal Society in 1828, by Sir John Herschel, and read on December 20th, 1827. In a letter with this Mr. Dunlop says:The following nebulæ and clusters of stars in the Southern Hemisphere were observed by me at my house in Parramatta, situated 6" of a degree south and about 1.78" of time east of the Brisbane Observatory. The reductions and arrangement have been principally made since my return to Europe."
People in Bright Sparcs - Dunlop, James; Rümker, Christian Carl Ludwig; Russell, Henry Chamberlain
© Online Edition Australian Science and Technology Heritage Centre and Bureau of Meteorology 2001
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