SOLAR ECLIPSE.

Otago Witness, Issue 2928, 27 April 1910, Page 37

SOLAR ECLIPSE.

ARRANGEMENTS FOR THE OBSERVATION.

HOW AMATEURS MAY ASSIST.

A total eclipse of the sun will take place on the afternoon of Monday, May 9. It will be visible as a partial eclipse over the whole of Australia and the northern half of Tasmania, but the only portion of the globe on land from which the phase of totality (namely, the complete obscuration of the sun) may .be seer is that part of Tasmania which lies south of an imaginary line running across the State from Cape Bougainville: on the east coast, through Parattah and the southern elopes of the Zeehan Ranges, to Harboxvr Signals on the west coast. Along this limiting line the duration of totality will be only momentary, but will gradually increase at localities further south, and will last from three to three and a-half mintues at such places as Hobart, Bruni Island, and others on the south coast. The occaeion must be regarded as offering to those who will be within this restricted area on May 9 the rare opportunity of witnessing what is generally admitted to be the most imposing of all celestial phenomena. It is only during the precious moments of a total solar eclipse that certain phenomena of the highest importance for the advancement of our knowledge of the sun can be seen and recorded. For this purpose many great expeditions went out from Europe and" America to observe the eclipses of the last 60 years, which involved extensive preparations, long journeys to distant lands, great expenditure of time, energy, and money, and, not infrequently, hardship and risk to health. In the present case, however (says the Adelaide Advertiser), no official expeditions are to be despatched to Tasmania from the older countries, owing, partly, to the low altitude of the sun at the time of the eclipse and the probability of bad weather, which will considerably reduce the chances of obtaining good results, and also to the circumstances that a moTe promising total eclipse of the sun will take place next year, for the observation of which European and American astronomers are already preparing to send expeditions to the Tonga Islands. Australian astronomers are thus expected to undertake the responsibiilty of carrying out the duties demanded by the eclipse of May 9. This matter was considered by the Australasian Association for the Advancement of Science at its Brisbane meeting in January, 1909, with the result that an eclipse committee was appointed by the council for the purpose of organising an expedition of Australian astronomers to observe the Tasmanian eclipse. The committee consists of Messrs P. Baracchi (Government Astronomer. Victoria), G. H. Knibbs (Federal Statistician), Senator Keating (Launceston), Professor Pollock (Sydney University), Professor M'Auley (Hobart University), Professor Chapman (Adelaide University), E. W. Cooke (Government Astronomer, West Australia), G. F. Dodwell (Government Astronomer, South Australia). R. H. Roe (Director of Education, Queensland), J. M. Baldwin, M. Sc. (Melbourne Observatory), C. J. Merfield. F.R.A.S. (Melbourne Observatory), Lieutenant Piesse (Hobart), Dr Coleridge Farr (New Zealand), and Dr W G. Duffield (hon. secretary). ARRANGEMENTS SO FAR CONCLUDED. It has been arranged! that an official expedition from the Melbourne Observatory shall go to Bruni Island. The observatories of the other States have been invited to join. Experienced astronomical observers, not officially connected with these institutions, and" who possess suitable eclipse instruments, are also invited to 3 °-Vf\ these simple camp accommodation will be prepared at their own cost. Persons without vea-y special astronomical training may be able to secure interesting records ot eclipse phenomena by means of ordinary moderate-sized cameras, small ordinary telescopes mounted on tripods, or even without instruments, and it is hoped that such persons may be found in large numbers in southern Tasmania ready to take a useful part at the critical time in the. observations of the eclipse. The Tourists' Association in Hobai't has undertaken to look after these observers, especially if they are visitors from the other States, to organise them into parties if desired, to direct them to the suitable localities in the neighbourhood of Hobart, at various elevated spots, including the summit of Mount Wellington, or at Bruni Island, or other places on the south coast, and to provide accommodation. Diagrams showing the various phases of the eclipse, the position of stars in the space surrounding the eclipsed sun, and other astronomical data will also be supplied to observers at the tourists' office. Travelling concessions to bona fide visitors to Tasmania for eclipse purposes have been granted by the railways and shipping companies. It will be necessary for those wishing to take advantage of the reduced rates to obtain a coupon signed! by the committee's representative in the State from which it is intended to begin the journey, for presentation to the railways or shipping companies concerned. Such coupons in this State must carry the signature of Professor Chapman. LOCALITIES. The totality phase of the eclipse may be seen from any places south of the nothern limit, as already defined, which command a clear view of the northwestern horizon. Owing to the mountainous nature of the country it will be necessary in the majority of cases for observers on the mainland to select elevated positions. In Hobart Mount Wellington obstructs the view of the north-Avestern horizon, and the best spots for observation will be found on the side of Bellerive. Mount Rumney may be quoted as a suitable station. The summit of Mount Wellington, given a fine and clear afternoon,

.will afford the most magnificent view of the .eclipse, and it is hoped that "manyj persons may take advantage of the opportunity. Port Davey is probably the most favourable position from the astronomical standpoint, owing to the slightly higher altitude if the sun, and the longer dura-; tion of the eclipse. This place is uninhabited and wild. It could be reached only) by special arrangements with some shipping company, and it would be necessary) to charter a vessel. Owing to these an<t many other difficulties, involving consider* able expense, the Eclipse Committee ha,s decided to take no action in regard to this locality; but it is expected that a private English expedition, under Mr F. ; M'Lean, will probably occupy this station.: THE WORK. The . joint permanent committee of the Royal Society and the Royal Astronomical Society of London has recommended that Australian astronomers should concentrate their efforts to secure photographia records of the structure of the coronal and not to undertake spectroscopic observations, as the conditions of the Tasmanian eclipse are unfavourable for this kind of work. Accordingly it has sent' out a set of instruments specially designed for and successfully employed afa other eclipses, which will be used by tha Melbourne Observatory expedition ati Bruni Island, according to a comprehen-i sive protographic programme, the corn.-, plete execution of which is the manf object of the expedition.