Solar Observations

Sun (Auckland), Volume IV, Issue 1053, 18 August 1930, Page 8

Solar Observations

EXPEDITIONS TO NIUAFOU BY tlio beginning of October, the party of New Zealand scientists to study the total eclipse of the sun in tha niontii will be busily occupied in preparing accommodation and equipment at the base at Xiuafou Island. The New Zealanders propose to leave Auckland b> the Niagara on September 23, but they will not have the advantages of Niuafou to themselves. There will be a large part> of Americans there, too.

Niuafou, known to numbers ol people for some obscure reason as Tin Can Island, is splendidly isolated. It is about midway between Samoa and the Lau, Qr Eastern Islands of the Fijian Group. The extraordinary thing about the solar eclipse of 1930 is that a speck of land such as Niuafou should be only a few miles from the centre of the belt of totality of the eclipse. The belt will slope downward from west to east across the Pacific, and on a latitude between Samoa and Fiji. It required a good deal of speculation to determine the best point from which observa tions could be made. Fotuna Island and Alofa Island came in for consideration, but the more insignificant Niuafou was chosen after precise calculations. So Niuafou, simply because of the strange chance which will bring the belt of totality near it, will flash into world prominence, though the period of fame, it is to be feared, w'ill he almost as fleeting as the obscuring of the sui*. After scientists, brandishing telescopes and muttering over mathematical tables, have disturbed its quietude for little more than the duration of this event, Niuafou will fall hack to its normal volcanic slumber* ings, with, perhaps, a pious hope for a second visitation from the belt of totality in years to come. The Dominion astronomer. Dr. C. E. Adams, has been preparing for the trip for many months, and, assisted by Mr. P. W. Glover, he is conducting experiments at Kelburn Observatory. Wellington, -with the instruments to be used at Niuafou. Finance yet remains a question affecting the personnel of the New Zealand party. The subscription list to the appeal fund was opened by Dr. Adams a few days ago, and amounts have been coming to hand steadily. Until the amount available can be re liably estimated, the personnel will not be known definitely. The Government announced that it could not finance the expedition, but assured the New Zealand Astronomical Society that a pound for pound subsidy would be given on contributions up to £2OO. The society set to work to raise £3OO —the amount thought to be necessary as the remainder of the funds for the expedition.

Three days after leaving Auckland, the expedition will reach Suva and will be taken by H.M.S. Laburnum to Niuafou. The means of returning to the Dominion at the end of October has not been definitely arranged. Dr. Adams has been communicating with Mr. C. S. Ramsay, a trader resident at

Niuafou, regarding the arrangements at a base camp. The American expedition will proceed to Niuafou under the supervision of the United States Navy Department, and Commander C. H. J. Keppler, of the United States Navy, is to lead the expedition. Professor S. A. Mitchell, of the Leander McCormick Observatory, University of Virginia, who is one of the leading authorities of eclipses of the sun, and his assistant, Mr. Kempton Adams, will be in charge of the spectrographic work. Professor R. W. Marriott and Dr. Weld Arnold will conduct the coronal photography and will make observations for the Einstein effect. Mr. B. P. Sharpless will be engaged on coronal photography, and Mr. J. J. Johnson will be photometric observer. Dr. T. A. Jaggers will probably accompany the party to make seismic and volcanic studies. Important scientific discoveries have been made from eclipses of the sun, and this explains the intensive arrangements which have been faced to take scientific parties, with a great deal of valuable equipment, to such a remote island as Niuafou. The discovery of the presence of helium in the sun was made during the eclipse of IS6B. This was 27 years before helium was found to be a constituent of one of the rare earths, cleveite. The eclipse of May 29, 1919, afforded an opportunity to prove Einstein’s generalised theory of relativity by showing that light was attracted by the sun and deflected from a straight path. This will be one of the astronomical questions for observation at Niuafou. In a total eclipse of the sun by the moon the diameter of the moon’s shadow cast on the earth averages about 150 miles only and sweeps rapidly across the face of the earth from west to east. The longest time the total eclipse of the sun by the moon can be visible at any place is little more than seven minutes. Yet scientists are only too ready to delay their studies in their own countries, devote months of time to preparations for the tour, undertake long sea journeys to diminutive Niuafou, risk the dangers of landing valuable scientific instruments during a treacherous Pacific swell, tolerate the discomforts of a temporary existence on a small island merely for a number of observations crowded into the brief space of seven minutes. To ordinary people, this is somewhat amazing, but everyone will recognise that Niuafou is really being flattered by ail this attention, even though an accident of the universe is selecting the small island for distinction.