CHAPTER VIII.

ASTRONOMY AND GEODESY IN AUSTRALIA : Part 2.

By Pietro Baracchi, F.R.A.S.,

Government Astronomer of Victoria.

“The Commonwealth of Australia; Federal Handbook, prepared in connection with the eighty-fourth meeting of the
British Association for the Advancement of Science,
held in Australia, August, 1914.”
pg.326-390. (1914)

By British Association for the Advancement of Science.
Federal Council in Australia, Australia.
Commonwealth Bureau of Census and Statistics, George Handley Knibbs

1. ASTRONOMY.

(a) Astronomical work done by Navigators, Surveyors, etc., for
Geographical Purposes.

Sir Thomas Brisbane laid the foundation of Australian astronomy in 1821, but the record of astronomical observations made on Australian soil commences half a century earlier ; as is well known, Captain Cook was selected by the British Admiralty, chiefly for his astronomical qualifications, “to conduct his famous expedition to the islands of the Pacific for the purpose of observing the transit of Venus of 1769, which he successfully accomplished at Otaheite, after which he discovered and visited several islands in the Pacific, and eventually re-discovered New Zealand on the 6th October, 1769, and observed the transit of Mercury on 9th November, at a place on the north-east coast, now called Mercury Bay, and sailing north, on 31st March, 1770, he discovered New Holland, landed at Botany Bay, and (on 22nd August, 1770) took possession of the eastern coast of Australia in the name of Great Britain” (1). *

In regard to longitudes obtained by lunar distances, Cook wrote “This method of finding the longitude at sea can be depended upon to within half a degree, which is a degree of accuracy more than sufficient for all nautical purposes.”

From Captain Cook’s astronomical observations made on Australian soil in 1770 was derived the first value on record of the longitude of Port Macquarie, Sydney, viz., 151° 11′ 32″ east of Greenwich, which is almost identical with that determined by Flinders 33 years after (151° 11′ 49″).

Captain John Hunter and Lieutenant Bradley determined the longitude of Port Jackson by a series of lunar distances, observed between 14th March and 28th April, 1788 (Hunter’s Historical Journal, pp.87-88). On 17th August, 1788 “we began at this time to take equal altitudes for ascertaining the exact rate of the time keeper.”

* A list of the authorities referred to in these pages is given in Appendix A. [pg.327]

In June, 1792, Captain Hunter, in a letter to the Admiralty said “The advantage of being able to ascertain the ship’s place in longitude by observations of the moon will be ever satisfactory, but more particularly through so vast a tract of sea, in which the error of the log may considerably accumulate.”

(2) The “first fleet,“ commanded by Captain Phillip, which brought out from Great Britain the colonists who formed the first permanent settlement upon the Australian continent, arrived at Port Jackson in 1788. Colonel Collins tells us, “Among the buildings that were undertaken shortly after our arrival must be mentioned an observatory, which was marked out on the western point of the cove, to receive the astronomical instruments which had been sent out by the Board of Longitude, for the purpose of observing the comet which was expected to be seen about the end of this year (1788). The construction of this building was placed under the direction of Lieutenant Dawes, of the Marines who, having made this branch of science his peculiar study, was appointed by the Board of Longitude to make astronomical observations in this country.”

The locality where this observatory is built is known as Dawes Point, and the structure is still there, though not used for astronomical purposes. This may be regarded as the first substantial observatory erected in Australia purely in the interests of astronomy.

The expected comet, however, was not seen, and nothing is known about Dawes’ astronomical work at this Observatory, except the determination of its geographical co-ordinates, which are latitude 33° 52′ 30″ S., longitude 151° 19′ 30″. A transit instrument was sent to him by Maskelyne, the Astronomer Royal, in 1791.

In regard to this comet, Russell wrote (6) “The comet, for which all these preparations were made, was that which had been observed in 1532 and 1661, and which was generally expected to return about the end of 1788 or the beginning of 1789. It was one of the twenty-four which Dr. Halley had used in his celebrated investigations, in which he proved that comets were subject to the then law of gravitation, and like all other astronomical bodies, revolved about some centre. In 1776, Maskelyne pointed out that this comet would be affected by the major planets, and that for the investigation of this important matter, it was very desirable that it should be observed in the southern hemisphere where it would first be visible ; hence the establishment of the Dawes Point Observatory.”

In one of the papers by Captain P.P. King (2) is given, amongst the longitude results of several navigators, the value of the longitude found by Admiral Don Jose D’Espinosa while at Sydney on the Corbetas Descubierta y Atrevida. This value reduced to Fort Macquarie, is shown as 10h. 4m. 51.91s., which is within a fraction of a second of time of the latest accepted value, and is very probably nearer to the true value than that found by any other navigator.

For more than 30 years after Dawes’ watches for the comet, the astronomical record rests entirely on navigators and explorers.

It was during this period that French expeditions were moving about in Australian waters, while surveys of the coast and explorations inland were being conducted by such nautical men as Bass, Flinders, Murray, and [pg.328] King, and the first explorers inland — Gregory, Blaxland, Evans, Oxley, Cunningham, Frazer, Hume, and others. Skilled astronomical observers, and even accomplished astronomers were to be found among these explorers, and the sun, the moon, the planets, and the stars were, no doubt, closely watched and employed by them for the determination of their geographical positions.

Flinders, who first circumnavigated Australia in 1801 on the Investigator, was indeed an enthusiastic and most accurate observer of the heavenly bodies. It was he who trained Sir John Franklin, then a midshipman on the Investigator, in astronomical work. John Crossley, of Greenwich Observatory, was appointed by the Admiralty as the astronomer of the expedition, but left the ship at the Cape of Good Hope, to return home invalided, and Flinders wrote to the authorities offering to undertake the astronomical work himself, with the help of his brother Lieutenant Sam W. Flinders, but the Admiralty sent out to him another astronomer—Inman—who accompanied Flinders during the latter part of the voyage (3). Inman, on his return to England, became Professor of Astronomy, at the Royal Naval College of Portsmouth.

The amount of Flinders’ lunar observations is remarkable, both for its fine quality and its large quantity. His value of the longitude of Fort Macquarie (Sydney), “151° 11′ 49″” east of Greenwich, is probably within one mile of the true value which, considering the instrumental limitations and the inaccuracy of the lunar tables in his day, may well be accepted as a result of the highest accuracy attainable at the time. In his Voyage to Terra Australia, are given the geographical co-ordinates of many places on the south coast of Australia (Vol. I., 1814), App., page 259.

(2) Lieutenant (afterwards Admiral) P. P. King, son of Governor King, arrived at Port Jackson in September, 1817. He had been sent by the British Government to complete the surveys of the coast of New South Wales, which, then, extended from South Cape in Tasmania, latitude 43° 39′ S. to Cape York, 10° 37′ S.

He made four voyages, extending over four years, from 1817 to 1822, during which he determined the longitude and latitude of a large number of points on the coast.

The results of the survey were published in his work A Narrative of a Survey of the Inter-tropical and Western Coasts of Australia (2 Vols., 8vo., London, 1847).

From 1826 to 1830 he was in command of two ships—Adventure and Beagle—conducting surveys on the southern coasts of South America. Shortly after, he retired from active service and settled in New South Wales, where for the rest of his life he continued to devote himself to scientific work, “during his residence at Dunhered, from 1832 to 1839, and at Tahlee, Port Stephens, to 1848, kept his observatory in full work with the transit and other instruments” (2).

The results of his astronomical work are contained in two papers which were printed “at his own private printing press, apparently for private distribution, a copy of each of which is in the possession of his family.” and in another paper, containing the first five years observations at Tahlee, which was published in the Tasmanian Journal, No. 6, a copy of which is [pg.329] in the Sydney Observatory, with the remainder of the observations in MSS. In one of the two papers first mentioned are recorded “the observed transits of the moon and moon culminating stars over the meridian of Tahlee, Port Stephens, New South Wales, from 1843 to 1849, and the resulting longitudes from them. Also observations of eclipses of the sun and occultations of the fixed stars by the moon at the same place.” The derived longitude of the station is 10h. 8m. 11s.

“The second paper gives a description of the instruments in the observatory and the observations for determining the latitude of Tahlee, 1841 to 1848. These observations were made with an altazimuth. Nearly 300 separate star observations for latitude are recorded, from which the latitude 32° 40′ 17.74″ is derived. Also a list of about one thousand places for which the geographical co-ordinates are given.“

Admiral King published in addition eight papers in the Monthly Notices of the Royal Astronomical Society, “Four refer to comets, amongst others the great comet of 1843 ; one to an occultation of Jupiter and his Satellites ; another to a lunar eclipse ; another to a transit of Mercury ; and the last to a solar eclipse” (2).

Sir James Ross’ antarctic expedition arrived at Hobart (Tasmania), in August, 1840, in the ships Erebus and Terror. Sir John Franklin was then Governor of that Colony.

A vigorous campaign for the acquisition of data in regard to the magnetic conditions of the globe was in course at the time, under the influence of Gauss and Sabine, and Sir James Ross established a magnetic station at Hobart, and also an astronomical observatory, where a transit instrument, an altazimuth, and astronomical clocks were permanently mounted. This station was placed in charge of Lieutenant Kay. Although terrestrial magnetism was the principal object, astronomical observations were systematically made and continued till 1854.

An elaborate investigation of the difference of longitude between Hobart and Port Macquarie (Sydney), Parramatta, and Cape of Good Hope, is included in the work of this observatory.

Last Update : 18th October 2014

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