Bruce Slee

The Radiophysics Field Stations and the Early Development of Radio Astronomy

During the period 1946–1961 Australia was one of the world’s leading nations in radio astronomy and played a key role in its development. Much of the research was carried out at a number of different field stations and associated remote sites situated in or near Sydney which were maintained by the Commonwealth Scientific and Industrial Research Organisation’s Division of Radiophysics. The best-known of these were Dover Heights, Dapto, Fleurs, Hornsby Valley and Potts Hill. At these and other field stations a succession of innovative radio telescopes was erected, and these were used by a band of young scientists—mainly men with engineering qualifications—to address a wide range of research issues, often with outstanding success.

Gordon James Stanley and the early development of radio astronomy in Australia and the United States

Following the end of the Second World War, the CSIRO Radiophysics Laboratory applied the expertise and surplus radar equipment acquired during the war to problems of astronomy. Gordon Stanley was among the first group of scientists and engineers to work in the exciting new field of radio astronomy. Like many of his contemporaries, he had a strong background in radio and electronics but none in astronomy. At the Radiophysics Laboratory, and later at Caltech, Stanley developed innovative new radio telescopes and sophisticated instrumentation which resulted in important new discoveries that changed, in a fundamental way, our understanding of the Universe. He was one of those who played a key role in the early development of radio astronomy both in Australia and the United States.

Early Australian optical and radio observations of Centaurus A

The discovery of the radio source Centaurus A and its optical counterpart NGC 5128 were important landmarks in the history of Australian astronomy. NGC 5128 was first observed in August 1826 by James Dunlop during a survey of southern objects at the Parramatta Observatory, west of the settlement at Sydney Cove. The observatory had been founded a few years earlier by Thomas Brisbane, the new governor of the British colony of New South Wales. Just over 120 years later, John Bolton, Gordon Stanley and Bruce Slee discovered the radio source Centaurus A at the Dover Heights field station in Sydney, operated by CSIROs Radiophysics Laboratory (the forerunner to CSIRO Astronomy and Space Sciences). This paper will describe this early historical work and summarize further studies of Centaurus A by other Radiophysics groups up to 1960.

The Contribution of the Division of Radiophysics Potts Hill Field Station to International Radio Astronomy

During the 1950s Australia was one of the world’s foremost astronomical nations owing primarily to the work of the dynamic Radio Astronomy Group within the Commonwealth Scientific and Industrial Research Organisation’s Division of Radiophysics. Most of the observations were made at the network of field stations maintained by the Division in or near Sydney, and one of the most notable of these was located at Potts Hill, the site of Sydney’s major water-distribution reservoirs.

The Contribution of the Division of Radiophysics Dapto Field Station to Solar Radio Astronomy, 1952–1964

By the early 1960s the Solar Group within the Commonwealth Scientific and Industrial Research Organisation’s Division of Radiophysics had established an international reputation for solar research, largely through the achievements of Paul Wild and his collaborators at the Division’s Dapto field station south of Sydney. This paper describes the innovative instruments found at this field station, the ways in which they were used to unravel many of the mysteries surrounding different types of radio bursts from the Sun, and some of the reasons for the success of the Dapto team.

The Early Development of Australian Radio Astronomy: The Role of the CSIRO Division of Radiophysics Field Stations

During the period 1946–1961 Australia was one of the world’s leading nations in radio astronomy and played a key role in its development. Much of the research was carried out at a number of different field stations and associated remote sites situated in or near Sydney which were maintained by the Commonwealth Scientific and Industrial Research Organisation’s Division of Radiophysics. The best-known of these were Dover Heights, Dapto, Fleurs, Hornsby Valley and Potts Hill. At these and other field stations a succession of innovative radio telescopes was erected, and these were used by a band of young scientists—mainly men with engineering qualifications—to address a wide range of research issues, often with outstanding success.

The Sun Has Set on a Brilliant Mind: John Paul Wild (1923–2008), Solar Radio Astronomer Extraordinaire

In this short paper we pay tribute to our long-time colleague, mentor and good friend, Paul Wild (FAA, FRS, FTSE) and briefly review his major contributions to solar radio astronomy from 1941 when he joined the CSIRO’s Division of Radiophysics until 1971 when he became Chief of the Division. During this period he made important contributions to our understanding of solar physics with his development of the Penrith and Dapto radiospectrographs, the Dapto Swept-frequency Interferometer and the Culgoora Radioheliograph. These instruments revealed for the first time the presence of charged particles and shock waves travelling through the solar corona, and their potential effects on ‘space weather.’

A search for electron cyclotron maser emission from compact binaries

Unipolar induction (UI) is a fundamental physical process, which occurs when a conducting body transverses a magnetic field. It has been suggested that UI is operating in RX J0806+15 and RX J1914+24, which are believed to be ultracompact binaries with orbital periods of 5.4 and 9.6 min, respectively. The UI model predicts that those two sources may be electron cyclotron maser sources at radio wavelengths. Other systems in which UI has been predicted to occur are short period extrasolar terrestrial planets with conducting cores. If UI is present, circularly polarized radio emission is predicted to be emitted. We have searched for this predicted radio emission from short period binaries using the Very Large Array (VLA) and Australian Telescope Compact Array (ATCA). In one epoch, we find evidence for a radio source, coincident in position with the optical position of RX J0806+15. Although we cannot completely exclude that this is a chance alignment between the position of RX J0806+15 and an artefact in the data reduction process, the fact that it was detected at a significance level of 5.8 sigma and found to be transient suggests that it is more likely that RX J0806+15 is a transient radio source. We find an upper limit on the degree of circular polarization to be similar to 50 per cent. The inferred brightness temperature exceeds 10(18) K, which is too high for any known incoherent process, but is consistent with maser emission and UI being the driving mechanism. We did not detect radio emission from ES Cet, RX J1914+24 or Gliese 876.

An Overview of W.N. Christiansen’s Contribution to Australian Radio Astronomy, 1948–1960

In 1948, an accomplished industrial physicist who had harboured a long-term ambition to become an astronomer joined the newly-formed Radio Astronomy Group in the CSIR’s Division of Radiophysics in Sydney, Australia. Thus, W.N. (‘Chris’) Christiansen (1913–2007) began a new career in the fledgling field of radio astronomy. This paper reviews Christiansen’s contribution to both instrumentation development and scientific research during the first phase of his career in radio astronomy, covering his work at the Potts Hill and Fleurs field stations prior to his resignation from the Division of Radiophysics in 1960.

A Retrospective View of Australian Solar Radio Astronomy 1945–1960

The Solar Radio Astronomy Group within the Commonwealth Scientific and Industrial Research Organisation’s Division of Radiophysics established an international reputation for solar research by the early 1960s. This paper examines some of the reasons for this success under four main headings: (1) Serendipity and timing; (2) Innovative design; (3) Support and funding; (4) Early outstanding scientific results. The achievements are compared chronologically with other significant contributions from elsewhere.