CHAPTER VIII.

ASTRONOMY AND GEODESY IN AUSTRALIA : Part 5.

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

(d) Australian Expeditions on Special Astronomical Occasions.

There were five occasions upon which the official astronomers of Australia recognised it as their duty to organise astronomical expeditions for observing important astronomical phenomena at places remote from their permanent observatories.

These occasions are—

1. The total eclipse of the sun of December, 1871 — at Eclipse Island, of the extreme north of Australia ;

2. The transit of Venus of December, 1874 ;

3. The transit of Venus of December, 1882 ;

4. The total eclipse of the sun of May, 1910 — at Bruni Island, in the South Pacific ;

5. The total eclipse of the sun of April, 1911 — at Vavau (Friendly Island).

1. This eclipse occurred on the 11th December, 1871. The path of totality crossed the Gulf of Carpentaria, touching Australia near its extreme northern points.

The proposal to fit out an expedition to observe the eclipse was made by the late Professor Wilson, and, on the recommendation of the Royal Society of Victoria, the Governments of Victoria and New South Wales authorised their respective astronomers — R.L.J. Ellery and H.C. Russell — to organise a party of observers suitably equipped for the purpose.

The locality selected for observation was a small island off the north coast, called, since. Eclipse Island. The Queensland Government provided the, then new, steamer Governor Blackall to carry the expedition to its destination and back.

The party consisted of the principal assistants of the Melbourne and Sydney Observatories and a large number of other observers recruited amongst the most eligible in the colonies.

The expedition was provided with the 7¼-in. equatorial, by Merz, of the Sydney Observatory, upon which was mounted a camera with lens of 3 inches aperture and 30 inches focal length ; the 4½-in. equatorial of the Melbourne Observatory, and several other smaller equatorial telescopes, all driven by clockwork ; photographic and spectroscopic apparatus fitted for the purpose. Special instruments, adapted for the occasion, had been forwarded by the Eclipse Committee of the British Association for the service of the expedition.

The expedition started from Sydney on 27th November, 1871, reached Eclipse Island on 7th December, and had the instruments ready by the 10th December, the day before the eclipse. On the 11th, unfavourable weather prevailed, and the sky was overcast during the whole time of totality.

Thus the expedition failed in its main object. [pg.363]

2. For the observation of the transit of Venus, in 1874, the official astronomers of the time — Ellery, Russell, and Todd — organised various parties, which were sent to occupy favourable spots in their own respective colonies.

In the colony of Victoria, Ellery selected, in addition to the Melbourne Observatory, where he himself and his assistants observed the transit, three subsidiary stations. These were—

Mornington, on the shores of Port Phillip Bay, and about 30 miles south of Melbourne ;

View Hill, Sandhurst, 86 miles north-west of Melbourne ;

Glenrowan, 150 miles north-east of Melbourne.

The observations at the Melbourne Observatory were directed by Ellery using the 8-in. equatorial, an 18-in. altazimuth, the Grubb 4-ft. reflector, and Dallmeyer’s 4-in. photoheliograph. Good observations of internal contact at “Ingress” and “Egress” were obtained. Many micrometric measurements of diameter of Venus were made by a double image micrometer, and physical phenomena well observed. Several photographs were secured, both with the photoheliograph and the great telescope.

The party at Mornington was in charge of Professor Wilson, of the Melbourne University; its equipment consisted of a 4½-in. equatorial, by Troughton and Simms, with which micrometric measurements and contact observations were made ; fair results of “Ingress” and “Egress” phenomena were obtained.

At View Hill, Sandhurst, Mr. C. Moerlin (assistant of the Melbourne Observatory) directed the operations. The instrument employed was an equatorially-mounted telescope, with objective 6¾-in. aperture, by Ertel, of Munich, provided with a double image micrometer. Cloudy weather prevented contact observations at “Ingress,” but some satisfactory results of “Egress” phenomena were obtained.

At Glenrowan, the party was in charge of Messrs. A. C. Allan and James Gilbert. The instruments employed were a 4½-in. equatorial, by Cooke and Sons, and a reflecting telescope, by Browning, 8½-in. aperture, equatorially mounted. Observations of “Ingress” were made satisfactorily in clear weather, except the first external contact, but no observations of “Egress” could be made, the sky being overcast.

In New South Wales, Russell, with the aid of the local Royal Society, was able to obtain sufficient encouragement and assistance from his Government to carry out the extensive preparations which he had planned with the object of securing observations on the eventful day of 9th December, 1874, at four different places in his colony. (6)

These were—

The Sydney Observatory ;

Eden, on the north shore of Twofold Bay, 350 miles south-west of Sydney ;

Goulburn, 134 miles south-west of Sydney, 2,071 feet above sea level ;

Woodford, in the mountainous district, 50 miles west of Sydney.

Parties were despatched to these places equipped with equatorially-mounted telescopes, fitted with apparatus for photographing the sun, and provided with means for determining time, material for obtaining upward of 200 pictures of the sun, observing huts, and all necessary appliances. [pg.364]

(21) At Sydney, the observers were directed by Russell ; the instruments employed were the 11.4-in. equatorial, by Schroeder, fitted with photographic apparatus, which could be quickly removed and mounted again ; a 4¾−in. equatorial, by Troughton and Simms ; and a 10-in. Browning silvered glass reflector.

At Eden, the Rev. W. Scott conducted the work ; the instruments used were a 7¼-in. equatorial, and two other smaller achromatic telescopes, with objectives 4¼ inches and 3¼ inches aperture respectively.

The station at Goulburn was occupied by Captain Hixson ; this party was provided with an achromatic telescope of 6 inches aperture, equatorially mounted and fitted with a camera ; also two smaller equatorial refractors of 3¾ inches and 3¼ inches aperture.

At Woodford, the observing party was in charge of Surveyor-General Adams. The observations were made with 3½−in. equatorial, and a 4-in. photoheliograph was employed for obtaining pictures of the sun. This station, in addition to the provisions made as at the other three places for taking 220 pictures, had a supply of 30 Janssen plates, each to hold 60 pictures.

Mr. Tebbutt observed the transit independently at his observatory, Windsor, with a 4½-in. equatorial. He had fine weather, and obtained accurate times of the beginning and end of the transit. (18)

In South Australia the transit was observed—

By Mr. Todd, at the Adelaide Observatory, the instruments used being the 8-in. equatorial, by T. Cooke and Sons, and a camera arranged to give an enlarged picture of the sun.

By T. D. Smeaton, J.P., at his residence. North Adelaide, using an excellent 3i-inch equatorial by Cooke and Son.

By F. C. Singleton, on the grounds of the Adelaide Observatory, using a 3-in. equatorial.

By A. W. Dobbie, at his residence, 2 miles north-east of the Adelaide Observatory, using an 8½−in. silvered glass reflecting telescope.

The weather was unfavourable at Adelaide up to a short time after “Ingress” and was only intermittently clear afterwards.

Todd obtained a few micrometric measurements, and made some observations of the approach of internal contact at “Egress.”

Messrs. Smeaton, Singleton, and Dobbie were able to observe and record the times of internal and external contact at “Egress.”

On the whole, Australia acquitted itself with credit on the occasion of the transit of Venus of 1874, and the Australian results form an important part in the investigation of the solar parallax, based on the observations of this transit.

3. The Australians had no opportunity of observing the complete set of phenomena of the transit of Venus of 7th December, 1882, as the beginning of the transit took place before sunrise. The importance of securing observations of the other phases was, however, fully understood, and extensive preparations were made accordingly.

In Victoria, Ellery sent out two parties from the Melbourne Observatory — one to Hobart, and one to Sale, Gippsland &@8212; Ellery himself remaining stationed at the Observatory in Melbourne. [pg.365]

The instruments employed at these three stations were the same as those with which observations of the previous transit had been made.

Ellery and White had fine weather and obtained good results.

The weather in Gippsland was unfavourable, and no

In New South Wales, Russell organised, equipped, and trained five expeditions, which he was able to supply in each case with two equatorially-mounted telescopes of 6-inch and 4½-inch aperture. Fifteen observers took part in the work. The five stations occupied by these parties were Port Macquarie, Clarence River, Dromedary, Katoomba, and Lord Howe Island. Russell and his staff were stationed at the Sydney Observatory.

None of these parties were successful, owing to adverse weather conditions.

Tebbutt, at the Windsor Observatory, met with similar ill fortune. Thus no contribution was made by New South Wales observers upon the transit of Venus of December, 1882.

The Government Astronomer of South Australia—Mr. Todd—observed the transit at Wentworth with a 4½−inch equatorial. He me with fine weather, and his programme of observations was successfully carried out. (15)

4. The southern parts of Tasmania and Bruni Island were the only localities from which the total eclipse of the sun of 9th May, 1910, could be seen. The chance of successfully observing this eclipse was very small on account of he low altitude of the sun at the time of totality, and of the unfavourable and severe weather conditions generally prevailing in these particular localities so late in the autumn. It was known that, owing probably to this uncertainty and to the great length of the journey involved, no official expedition was to be despatched to Tasmania on this occasion, and only one private party, conducted by Mr. Frank McClean, was expected to come out in due course to occupy some spot within the belt of totality.

Under the circumstances it was clearly the duty of Australian astronomers to deal with the Tasmanian eclipse.

Dr. W. G. Duffield, of South Australia, now Professor of Natural Philosophy at the University College of Reading, brought this matter before the Council of the Australasian Association for the Advancement of Science at its Brisbane meeting, of January, 1909, and that Council appointed a committee, with Dr. Duffield as secretary, for the purpose of taking steps to ensure that efficient preparations were made to observe the eclipse in question. The result was that the Government of Victoria provided its own astronomer with the required means for organising and fitting out an eclipse expedition to Bruni Island, which was done.

The Joint Permanent Eclipse Committee of the Royal Society and Royal Astronomical Society supplied a part of the equipment to this expedition.

Unfortunately it is needless to detail the elaborate preparations made since the day remained completely overcast, and nothing was seen of the eclipse, except a general darkening of the landscape.

Mr. Frank McClean and his party, who were stationed at Port Davey, some 60 miles to the west of us, and Mr. Walter Gale, of Sydney, who had purposely gone to Hobart on his own initiative to observe the eclipse from a position in that city, were also unable to see the eclipse owing to cloud and rain. [pg.366]

5. At the Sydney meeting of the Australasian Association for the Advancement of Science, in January, 1911, the same Eclipse Committee was reappointed with the object of forming an Australian expedition for the observation of the total eclipse of the sun of 29th April, 1911, at Vavau, one of the islands of the Tonga Group in the Pacific Ocean. Dr. Duffield being in Europe, Professor Moors, of the Sydney University, was appointed secretary to the committee.

The committee, having succeeded in obtaining a subsidy of £500 from the Commonwealth, was able to organise and equip a party.

The equipment of the expedition comprised principally —

4-inch photoheliograph (Melbourne Observatory) ;

4½-inch equatorial telescope (Melbourne Observatory), with two large portrait lens cameras attached ;

One coronograph (Perth Observatory) ;

One coronograph (Adelaide Observatory) ;

One 16-inch coelostat, lent by the British Eclipse Committee ;

One 12-inch coelostat, lent by the British Eclipse Committee ;

One coronograph (Sydney University) ;

One 6-inch refracting telescope, with camera attached ;

One smaller equatorial ;

A large altazimuth, for time determination (Perth Observatory) ;

Also several cameras of various sizes, chronometers, subsidiary apparatus, observing sheds and huts, living tents, and camp material.

On the morning of the eclipse all instruments were in good order and adjustment and the observers had been thoroughly drilled.

The weather was unpromising, and the face of the sun was obscured intermittently by passing clouds up to the beginning, and during a considerable part, of the phase of totality. Each observer, however, accomplished his allotted programme, and some 45 plates were exposed during the three and a half minutes of totality. The plates were developed the dame evening, and the results obtained were found to be much better than was at first expected.

The form of the corona was found to correspond to the type which had been observed on several previous years of minimum solar spots.

Although this single result brings no new knowledge of eclipse phenomena, yet, taken as additional evidence concerning an important characteristic of the solar corona which is obtainable only on relatively rare occasions, it becomes a valuable contribution to the store of eclipse records.

Last Update : 18th October 2014