page_title: Ben Gascoigne
section_title: Mount Stromlo
hierarchical_section_title: Ben Gascoigne / Mount Stromlo
caption_attribution_description: English: Siding Spring Mountain viewed from Belougery Split Rock. 3x optical zoom.
context_page_description: Sidney Charles Bartholemew "Ben" Gascoigne AO was a New Zealand-born Australian optical astronomer and expert in photometry who played a leading role in the design and commissioning of Australia's largest optical telescope, the Anglo-Australian Telescope, which for a time was one of the world's most important astronomical facilities. Born in Napier, New Zealand, Gascoigne trained in Auckland and at the University of Bristol, before moving to Australia during World War II to work at the Commonwealth Solar Observatory at Mount Stromlo in Canberra. He became skillful in the design and manufacture of optical devices such as telescope elements.
  Following the war, Gascoigne and astronomer Gerald Kron used newly modernised telescopes at Mount Stromlo to determine that the distance between our galaxy and the Magellanic Cloud dwarf galaxies had been underestimated by a factor of two. Because this measurement was used to calibrate other distances in astronomy, the result effectively doubled the estimated size of the universe.
context_section_description: Following the end of the war Woolley redirected the Commonwealth Observatory from solar research towards the study of stars and galaxies. It took time to get the old and unused telescopes back up to working condition: they had to be overhauled and refurbished, and in one case rebuilt from scrap. Woolley got funding approval from the Prime Minister for construction of a 74-inch telescope, but it would not be finished for years. Gascoigne began to work in the nascent field of photoelectric photometry, using electrical devices to measure the brightness of stars more accurately than had been possible using photographic techniques. In 1951, with equipment brought by visiting astronomer Gerald Kron from California's Lick Observatory, he observed Cepheid variable stars, which are used to measure astronomical distances. Granted nine months of observing time on the Observatory's Reynolds 30-inch reflector telescope – an extraordinary opportunity – Gascoigne, Kron and others surveyed Cepheid stars in both the Small Magellanic Cloud and, later, the Large Magellanic Cloud. They also examined the colours of star clusters in the Small Cloud.
  The research produced remarkable results: "it meant that the Magellanic Clouds were twice as far away as was previously thought, and if then the baseline is twice as long, the size of the universe is doubled." It also showed that star formation in the Magellanic Clouds had occurred more recently than in the Milky Way. The results overturned the prevailing view that our galaxy and the Magellanic Clouds had evolved in parallel. Gascoigne said of his work:
  When suddenly all this dropped into place, after I had been working away at it for quite a while, measuring more Cepheids in our own Galaxy and some in the Large Cloud, the feeling of triumph, the great feeling that I had really done something, was wonderful. I had joined the professional astronomers. Not only that, but I truly understood a problem, a proper problem...
   Subsequent research confirmed what were described as pioneering results, arrived at through very innovative techniques.
  In 1949, the Gascoignes' third child, daughter Hester, was born. Like many Observatory personnel, the Gascoignes lived in a staff residence on Mount Stromlo, which was a long difficult trip away from Canberra. It was cold and lonely, particularly for Rosalie, but they enjoyed the outdoors, and the landscape inspired Rosalie's creativity and later her artistic career. In 1960 they relocated to Deakin in suburban Canberra, and in the late 1960s they moved to another suburb, Pearce.
  In 1957, administrative responsibility for the Commonwealth Observatory was transferred from the Australian Government's Department of the Interior to the Australian National University (ANU), a move supported by both its director, Richard Woolley, and Gascoigne. This was an era of significant change at Mount Stromlo: in January 1956 Woolley had resigned as director of Mount Stromlo to take up a position as Astronomer Royal and director of the Royal Observatory Greenwich. He was replaced by Bart Bok, whom Gascoigne liked and under whose directorship he played a significant role. Also in 1957, the Mount Stromlo team began searching for a new field observatory site, due to the increased light pollution from Canberra's growth. The search was vigorously promoted by Bok, and after an examination of 20 possible locations, two were shortlisted: Mount Bingar, near Griffith, New South Wales, and Siding Spring, near Coonabarabran, New South Wales. Gascoigne was one of a group of scientists who visited Siding Spring Mountain as part of the search, and he was one of those who advocated this choice:
  We had to climb the last bit on foot ... [I was] the first astronomer to set foot on Siding Spring. I liked the look of the place right away, partly because it had such good features for astronomy – for example, the north and west faces had sheer cliffs that were very good for draining away the cold air – and because of its beautiful outlook, on the edge of the national park. It really is a wonderful place 
caption: Siding Spring Mountain in the Warrumbungles. The Anglo-Australian Telescope dome is on the crest.
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