The solar eclipse of 20 May 1947

Alan Hunter (apf6-04377r)

Alan Hunter a little over a year after the plane crash. Photo taken at the 7th General Assembly of the International Astronomical Union held in Zürich, Switzerland, August 11-18, 1948 and reproduced courtesy of University of Chicago Photographic Archive, [apf6-04377r], Hanna Holborn Gray Special Collections Research Center, University of Chicago Library (see below)

Although the Observatory did not mount its own expedition to observe this total eclipse, one of the Assistants, Alan Hunter, who later became the Observatory's Director, was selected as a member of the ill-fated British eclipse expedition to Araxa in Brazil.

The Astronomer Royal, Harold Spencer Jones, filled in some of the details in his 1947 Report to the Board of Visitors:

' Dr. Hunter was selected as a member of the British eclipse expedition to Brazil to observe the total eclipse of the Sun of the 20th May. This expedition, under the auspices of the Joint Permanent Eclipse Expedition, was in the charge of Dr. J. A. Carroll. Dr. Hunter assisted in the assembling and testing of the equipment prior to its dispatch by sea. The plane in which Dr. Hunter, in company with two other members of the expedition, was travelling to Brazil crashed at Dakar on the 13th April. The crash cost the lives of the two other members, but Dr. Hunter fortunately escaped with severe cuts and abrasions. As some of the optical equipment was also smashed, it was impossible to proceed with the expedition, which had to be cancelled.'

The three members of the eclipse party on the plane were originally expecting to travel to Brazil with their equipment by boat. The reason for the change of plan together with a description of the observing programme that it was proposed to carry out was published in the 17 May 1947 edition of Nature.

The plane, an Avro 685 York (G-AHEZ) operated by British South American Airways (BSAA), had six crew and nine passengers on board. After three unsuccessful attempts to land in poor visibility the plane made a hard landing which resulted in the undercarriage shearing off and the plane skidding along on its belly before breaking in two. At least seven of the occupants died. The National Archives hold images of the crashed plane.

The 12 July 1947 edition of Nature carried the following preliminary reports from around the world:

'Contrary to all expectation, based on the usual weather conditions in May, the expeditions to the west coast of Africa to observe the total solar eclipse of May 20 were uniformly successful, whereas those to Brazil were upset by cloudy conditions. In Santiago in Chile, conditions were cloudy but observations were made from an aeroplane above the clouds. The corona was reported as of the minimum type with equatorial streamers and polar plumes-an unusual form so near sunspot maximum. At Araxa in Brazil, the Czechoslovak party and the Swedish party under Dr. Öhman were clouded out. At Bocayuva, the Finnish party was able to carry out its time observations for the geodetic programme. The party at the same place from the American Geographical Society, the Georgetown University, Washington, and the Yerkes Observatory reports only partial success owing to clouds. Dr. van Biesbroeck secured plates of the star-field around the sun for the Einstein effect, and photographs of the corona and of its spectrum; accurate time observations of the contacts were obtained. Photographs were taken from an A.A.F. B 17 plane flying at 30,000 ft.; also a programme of ionospheric observations was successfully carried through.

In West Africa, both the Finnish and the Swedish expeditions were favoured by clear weather and were able to carry through their cinematograph programme for the determination of the contacts, on the scheme drawn up by Bonsdorff. The Swedish expedition under Dr. B. Aurell recorded cinematographically the crescent as well as the flash spectrum. The American party at Bocayuva also reports that, while there, long-exposure photographs of the southern Milky Way were taken and measurements made of the intensity of cosmic rays.'

 

Acknowledgements

The photo of Alan Hunter is reproduced courtesy of University of Chicago Photographic Archive, [apf6-04377r], Hanna Holborn Gray Special Collections Research Center, University of Chicago Library (see below)