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SOUTHERN ASTRONOMERS and
AUSTRALIAN ASTRONOMY


ASTRONOMY IN AUSTRALIA

Compiled by

HARLEY WOOD

SYDNEY OBSERVATORY

PRINTED AND PUBLISHED IN AUSTRALIA BY
V. C. N. BLIGHT, C.B.E., GOVERNMENT PRINTER
NEW SOUTH WALES 1973

29,63-A

INTRODUCTION

I have selected this following article because it gives some modern perspectives on the development and achievements of astronomy in Australia from roughly about the 1940s through to 1973. It was during the time when Australia was starting reaching its true zenith of theoretical and observational astronomy. This interesting publication was produced somewhere between late 1972 and early 1973.

The original copy was handed to me at only my second amateur astronomical meeting, and I even attended the celebratory lecture held before the sitting of Fifteenth (XV) International Astronomical Union (IAU) General Assembly in Sydney between 21st and 30th August 1973. This important major international scientific conference was well publicised, and was well received in the local amateur and professional astronomical community — deemed as a scientific celebration within this country. Coincidentally, the IAU was to again hold its Twenty-Fifth (XXV) General Assembly in Sydney between 13th and 26th July 2003 — almost exactly thirty years later.

Although this too was a great success, my own opinion thinks this 1973 event was far more important and influential. After the IAU event, the Australian Federal Government significantly increased funding for new facilities and better radio and optical telescopes. Australian astronomy did continue its ascent in the eyes of the world, whose real contributions continue to make its mark today in the international astronomical community.

Much of the information of this document was to promote Australian astronomy to the IAU delegates, and on some level is, frankly, just pure propaganda. However, this view would be a little superficial because much support was given to the Australian sciences during to, and prior, to this time.

Andrew James
Updated: 19th December, 2010


ASTRONOMY IN AUSTRALIA

It is fitting to prepare an account of astronomy in Australia at the time of the General Assembly of the International Astronomical Union in Sydney — the first assembly in the Southern Hemisphere. The most natural way to do this is to consider the institutions in turn and the most natural arrangement is to treat them in order of their foundation or their engagement in astronomy.


SYDNEY OBSERVATORY — Even at the time of the foundation of Sydney in 1788 an astronomer, William Dawes, established a small observatory with the duty of looking for a comet which Halley and Maskelyne had conjectured would return in 1789. Then in 1821, Governor Brisbane established his observatory at Parramatta. Governor Brisbanes observatory began pioneering work in southern astronomy, continued after his departure and remained until 1848.

Soon afterwards the need for astronomical facilities was again felt and the negotiations led to the establishment of Sydney Observatory in 1856 with W. Scott as the first astronomer. Work on positional astronomy has been carried on since that time. In 1887, H.C. Russell, known for pioneering work in astronomical photography, took part in the conference in Paris which led to the decision to compile the Astrographic Catalogue and under Dr H.W. Wood there has until recent times been a concentration of effort towards completing the work which was published in 53 volumes. When Melbourne Observatory closed in 1944 the responsibility for the Melbourne section was transferred to Sydney Observatory where it was completed, funds for publication coming from the I.A.U. Each of these two zones is equal to the largest undertaken by northern observatories together covering from −51° to the South Pole.

The old epoch plates of the Astrographic Catalogue and those taken for the Astrographic Chart are being used to derive proper motions of variable stars and of the stars in some areas of special interest such as star clusters. Observation of the positions of minor planets was begun in 1953 and has continued since then. In recent years the effort in this direction has been devoted mainly to work on those minor planets which have been selected for use in fundamental astronomy. Co-operation with Yale University Observatory in the photography of large areas of the southern sky led to the publication by Yale in recent years of the catalogues of these areas.

The observatory is at present using a wide angle astrographic lens made by Taylor, Taylor and Hobson to photograph the southern sky. The centres are selected so as to provide for full overlap which will facilitate reduction of the plate measurements by overlapping methods. The first zone to be photographed was centred in declination −51° and the work has proceeded outward from this. At the time of writing the centres being photographed are at −41° and −66° which should be completed before the time of the Assembly when the next zones outwards should be under way. [3]

Recently, approval was given by the Government for a search to find a site at which the work of the observatory could be carried on under conditions better than at the present one in the midst of a great city. The work on this project shows very clearly that an inland site, as well as taking us away from the light and smog of the city, will provide meteorological conditions vastly better than available at any place on the coast.


PERTH OBSERVATORY was instituted in 1896 with the appointment, of the first Government Astronomer, W.E. Cooke. A 15 cm meridian transit telescope and a 33 cm standard astrographic refractor were installed in 1900 and for the next 20 years work was concentrated on the Perth zone of the Astrographic Catalogue, −31° to −41°. Six volumes of meridian observations, containing positions for about 9,000 reference stars, were published by 1913; and between 1911 and 1920, 24 volumes of the Astrographic Catalogue appeared, covering the six declination bands centred at −32° to −37°. The plates for the remaining zones were measured at the Royal Observatory, Edinburgh, but financial restrictions prevented the publication of these results until 1949—52, when funds were made available by the I.A.U.

From about 1920 until the 1950s, the observatorys staff was seriously reduced. However under the late H.S. Spigl a reconstruction programme was started. First, the astrographic telescope was put into service again and, from 1958 to 1960, it was used for observations with a Markowitz Moon Camera. In 1961, a start was made on rehabilitating the meridian transit telescope, but this was cut short when the observatory buildings, which were close to the city centre, were demolished to make way for a large building.

The observatory was re-established in 1966 near Bickley under J.B. Harris about 30 km east of the city of Perth, in the forest which covers the lower Darling Range of hills. The astrographic telescope has been installed there, but the transit instrument has been retired. From 1967 to 1971, an expedition from the Hamburg~Bergedorf Observatory used their own 18 cm meridian transit telescope, modified to give automatic read-out of transits and circle readings, at Bickley for observations in the Southern Reference Star programme. At the conclusion of their programme, the telescope has been left at Bickley, on loan, to enable a meridian group to carry on in the Perth Observatory.

In April, 1971, a 60 cm cassegrain reflector, with f/75 secondary, was installed for observations in the Lowell-NASA Planet Patrol programme. A plate camera and f/13.5 secondary are available for star field photography when the telescope is not engaged in planet observations.

A 40 cm Newtonian (f/4.5) cassegrain (f/20) reflector built in the Physics Department of the University of Western Australia and installed at Bickley in 1969 is used for direct photography, photo-electric photometry and spectroscopy mainly by University staff and students.

The main effort of Perth Observatory, however, is still on positional astronomy. The meridian group is engaged in a programme on the stars of the FK4 Sup. Catalogue. The astrographic telescope is used mainly for positional observations of comets and minor planets, for investigations of orbits, and for cluster proper motions studies. Photometric observations in clusters, to supplement the proper motion investigations, are being started on the 60 cm Lowell telescope. [4]


MOUNT STROMLO AND SIDING SPRING OBSERVATORIES. Mount Stromlo Observatory is situated about 11 km west of Canberra within the Commonwealth Territory. The observatory was founded as the Commonwealth Solar Observatory in 1924 after tests of the quality of the site. The first Director was W. G. Duffield. It operated as a solar observatory until the period of directorship of R. v.d.R. Woolley when its activities were enlarged into the field of general astronomy and, to correspond to the wider sphere, the name was changed to the Commonwealth Observatory which first appeared on the annual report of 1935.

During the subsequent period under Woolley, B. J. Bok and the present Director, 0.J. Eggen, the facilities and activities of the observatory have been much widened. After a serious bushfire in 1952 the rebuilding programme included the establishment of a good workshop and later an optical shop and photographic laboratory. The telescopes at the observatory includes a 2.9 m reflector erected in 1955 and a 1.27 m reflector which was formerly the Great Melbourne Telescope” which has been very completely reconstructed. The observatory also has the 0.66 m refractor, which was left on Mount Stromlo after a period of use by the Yale-Columbia Observatories. The observatory acts as a host also to the Observatory of the University of Uppsala for whom a 0.66 m Schmidt telescope, is maintained at Mount Stromlo. In 1957 the observatory was transferred to the Australian National University and is now part of the Institute of Advanced Study.

The rapid growth of the city of Canberra and the realization that a greater proportion of clear sky would be available in other parts of the country led to an extensive site testing programme as a result of which. Siding Spring Mountain, near Coonabarabran, was selected as the site for a rapidly growing complex of equipment. This site is providing dark skies with a very good proportion of clear weather and good seeing conditions. Regular flights in light planes are maintained between the two centres. The telescopes already established at Siding Spring include 1.16 m and 0.6 m reflectors.

In April, 1967, the Governments of Australia and the United Kingdom announced an agreement to build a 3.8 m telescope and appointed the Anglo-Australian Telescope Board to supervise its construction. The plans were quickly completed and the construction of the telescope and its dome are proceeding in accordance with the timetable set out early in the project. It is expected that the reflector will be operational in 1974. At the prime focus the telescope will be f/3.3. There will be cassegrain ratios of f/8 and f/15 and a ratio of f/36. The mirror and secondaries form a Ritchey-Chrétien system with correspondingly wide field and a correcting lens system will be available at the prime focus. A full range of instrumentation will be associated with the telescope. The university plans to construct a 1.5 m reflector at Siding Spring in the near future and will also service a 1.2 m Schmidt camera being constructed by the British Science Research Council.

The observatories are equipped with a wide range of auxiliary equipment for their telescopes. There are photometric equipment of various kinds and spectrographs including a coudi spectrograph on the 2.9 m reflector. A large team of mechanical, electronic and computer engineers provide the astronomers with a strong back up in developing and maintaining the equipment. Some two dozen astronomers are well supported by seventy administrative and technical personnel responsible for the large workshop complex at Mount Stromlo.

Normally about six Ph.D. scholars are resident at the observatory. Mount Stromlo is the largest observatory in the Southern Hemisphere and its astronomers have worked in nearly all fields of astronomy and astrophysics. Although the emphasis changes with [5] [6 Image] change in personnel, the activity in recent years has been very much in the fields of stellar evolution, stellar atmospheres and stellar structure. The work has been pursued with the whole range of observational techniques in photometry and spectroscopy together with the associated theoretical effort. Cosmological problems, too, have come into prominence.



THE RADIOPHYSICS LABORATORY OF THE CSIRO under Dr E. G. Bowen began work in radio astronomy in 1945 with observation of activity on the sun. This led Dr J. L. Pawsey and his colleagues to establish a sea interferometer to obtain higher angular resolution and to examine other cosmic radio sources. Six field stations were established and the laboratory played a crucial part in the establishment of radio astronomy as an important branch of the science. Dr J.P. Wild, now chief of the laboratory, made detailed investigation of solar activity and commenced the significant metre wave spectroscopy. J.G. Bolton with colleagues located the galactic nucleus source in 1954, W.N. Christiansen produced the grating interferometer to obtain high resolution pictures of the sun and F. Kerr and colleagues made the survey of the southern Milky Way and Magellanic Clouds in the neutral hydrogen line. In 1953 the first cross telescope by B.Y. Mills was operating. R.X. McGee and others at Murraybank developed a multi channel receiver and made a survey of the sky for neutral hydrogen at a much faster rate than previously possible. The whole of the equipment used in the field stations was designed and constructed in the Radiophysics Laboratory. There was a stream of publications so great, more than 1,000 since 1946, as to defy summarization and many of the workers in the radio astronomy team went to important posts to establish radio astronomy departments in other institutions in Australia and overseas. The 64 m radio telescope was commissioned at North Goobang near Parkes on October, 1961. Specifications were decided upon by the laboratory staff in about 1956. Many of the outstanding features of this telescope have come from H.C. Minnett, B.F. Cooper and the famous aircraft designer Sir Barnes Wallis. Other cosmic radio astronomy field stations were closed down and a strong group of observers was assembled under the directorship of J.G. Bolton.

Valuable results soon followed. Polarization studies revealed Faraday rotation effects and the galactic and extra-galactic magnetic fields. Lunar occultations of radio sources observed with the telescope led to the discovery of a remarkable new object-the quasar and 21 cm observations on the Milky Way and the Clouds of Magellan in both neutral hydrogen line and radio continuum were gathered. The Parkes Catalogue of Radio Sources was built up and the spectra of sources was established as higher frequencies and more sensitive receivers became available. Bolton himself carried out his own optical observations at telescopes in California and at Mount Stromlo for identifications.

From 1964 interesting aspects of the nature and distribution of the hydroxyl line were uncovered aided by a receiver offering the choice of four frequency resolutions at a time when narrow band observations were needed for OH emission lines and wide band for the then new recombination lines of excited hydrogen.



Wild, continued his interest in the sun, designed the radioheliograph as a tool for fundamental studies of the solar atmosphere in general, and of the great explosions on the sun in particular. The radioheliograph operatesat a frequency of 80 MHz. It has 96 parobolic aerials spaced around a circle of diameter 3 km. The aerials are 13.7 m across, each mounted on a tower and driven to follow the sun. The instrument was designed and, except for some fabrication of steel structures, was built and erected at Culgoora near Narrabri by the staff of the laboratory.

In January 1968, the CSIRO Radiophysics Laboratory moved from the building it had occupied since its foundation in 1941 in the grounds of Sydney University to a new site near Epping, some 18 km from central Sydney. Bowen, who had been so successful in establishing the instrumental resources of his laboratory retired in 1971 and Wild was appointed head of the Division. There has been some rearrangement including the appointment of B.J. Robinson as head of the cosmic radio astronomy group and of S.F. Smerd of the solar radio astronomy.

Since July 1969, the Apollo 11 moon landing, the Parkes telescope has been a major instrument in the reception of transmission from the Apollo missions in connection wiyh which NASA has installed electronic equipment supplying technicians to operate it.

Recent improvements at Parkes include replacement of the reflecting surface by perforated aluminium panels enabling wavelengths of 1.2 cm to be used, improved feeding of the paraboloid achieved by the use of corrugated horn feed structures, and cryogenic receivers at 6 and 3.4 cm with impetus to line and continuum survey work. Ambient temperature parametric amplifiers at 21, 18, 11, and 9 cm have produced new astrophysical results. The processing of data is greatly facilitated by a comprehensive PDP-9 computer and peripherals. A digital correlator of 1,024 channels and 2 bit operation designed and built recently at Epping will revolutionize line operation.

The Cosmic Radio Astronomy Group is currently engaged in the investigation of quasars and galaxies and their identification, pulsars, polarization, Milky Way continuum surveys at low wave-lengths, atomic and molecular line work, supernovae remnants and other non-thermal galactic objects, the investigation of the Magellanic Clouds.

Since 1964 the investigation of OH gas has played a large part in the general understanding of galactic dynamics in the galactic centre region.

Early surveys were made of hydrogen recombination lines and the first ever observation of a radio p-transition of hydrogen was reported from Parkes in 1967. The work is continuing. The most complete survey of 21 cm absorption in discrete-source spectra yet published was issued at the beginning of 1972. The two component structure of inter~stellar hydrogen and its physical properties were firmly established.

Since about 1970 the number of interstellar molecular compounds, discovered mostly in U.S. institutions, has risen to more than a score. However, the Radiophysics Laboratory has had success in recent months with the discoveries of thioformaldehyde and methyleneimine and has now been credited with the discovery of six interstellar molecular lines. In this research project the laboratory has been assisted by chemists of Monash University.

There are plans to enter the technically difficult field of millimetre waves where a large proportion of interstellar molecular lines are expected to be located. [9]

The radioheliograph at Culgoora supplies each second a 80 MHz radio picture over an area of 2° × 1.6° centred on the sun. The pictures which display right- and left-hand circularly polarised emission are a record of the solar storms and outbursts. The events are classified with another instrument, a solar radiospectrograph which operates over a very large frequency range 8 Hz to 8 GHz.

In July 1969, a typical solar flare began with the usual burst of radio waves which suddenly broke into sharp pulses of striking regularity at intervals of 2-7 sec. lasting for about 50 pulses. At the same time a solar shock wave was seen to be travelling out from the flare explosion, and shortly after, cosmic rays were observed by detectors on a satellite. Researchers in the Division have found a simple theory which explains the sequence of events and provides a clue to the question as to how solar cosmic rays are generated.

Work is in progress to convert the radioheliograph into a three frequency instrument -160, 80, and 43.25 MHz — thus supplying simultaneous information at three different heights above the solar surface.


THE PHYSICS DEPARTMENT OF THE UNIVERSITY OF ADELAIDE (Professor J. H. Carver) began radio meteor studies in 1950. The work is directed towards a study of atmospheric properties by observation of the drift of meteor trails and the determination of meteor orbits. The orbits of 1,670 meteors were measured during the period December, 1968 to June, 1969, with a limiting radio magnitude +8. At least 30 per cent of these belong to streams. Of particular interest is a new group of high inclination low eccentricity streams. Deceleration measurements indicate a low density for the majority of meteoroids.

Interplanetary scintillation of radio sources has been observed since 1968, largely using the CSIRO radioheliograph at Culgoora. the Crab Nebula since June, 1969, has given a complete, two-dimensional brightness distribution of the broadened source.

An array of three spaced receiving stations recently completed near Adelaide, operates on the two frequencies 111.5 and 236 MHz to investigate the detailed properties of the solar wind, using interplanetary scintillation and will also study the angular structure of radio sources using both scintillation and long-baseline interferometry. [10]

The Universities of Adelaide and Tasmania have collaborated in a series of X-ray astronomy investigations using rocket and balloon payloads. Among the discoveries of this group was the first established variable X-ray source CEN XR-2. Energy spectra have been studied (mainly above ~20 kev) for a number of southern X-ray objects.

The present cosmic ray programme on extensive air showers generated by primary cosmic rays of energy in excess of 1014 ev and, in particular, the radio signals generated by showers in their passage through the atmosphere is expected to yield information about their chemical composition at these high energies.

Rocket and satellite observations of the solar ultraviolet flux have been made in collaboration with the Weapons Research Establishment and cover the range 1,050-1,680 Å using a number of broad band photometers. The reflectivity of the moon measured from rockets in the near ultraviolet (2,400-2,900 Å) and at the wavelength of Lyman α (1,215 Å); is substantially less than at visible wavelengths. Recent work in the laboratory includes vacuum ultraviolet studies of gases of atmospheric and astrophysical importance.


THE WEAPONS RESEARCH ESTABLISHMENT AT SALISBURY, South Australia, has conducted a series of interferometric studies of radio sources using pairs of radio telescopes of the U.S. Deep Space Network. Observations using a trans-Pacific baseline have provided new information about the small scale angular structure of quasi-stellar objects. The work has involved experimenters from the Australian Department of Supply, the Owens Valley Radio Observatory, the Jet Propulsion Laboratories and the University of Adelaide.


THE DIVISION OF PHYSICS OF CSIRO (Chief, Dr R. G. Giovanelli) began optical observations of the sun in the late 1950s with three instruments. The first of these was a 13 cm flare patrol telescope which was set up with funds provided for the International Geophysical Year, 1957-58, and initially was located on the roof of the N ational Standards Laboratory in Sydney. A year or so later a small solar observatory was established at Fleurs, some 50 km west of Sydney. The equipment at this observatory consisted of two small but highly specialized instruments designed to photograph the sun with good spatial resolution in white light and in the Hα line of hydrogen. Over a number of years, these telescopes were used for a systematic programme of photography of the fine structure of sunspots, the solar granulation, and the chromosphere. In spite of the small aperture of the telescopes employed, namely 13 cm, the resolution achieved with these instruments was about 1″ of arc on the photosphere and 1.8″ of arc on the chromosphere.

The same period saw the development in the laboratory of a tunable birefringent filter for the Hα line having a bandwidth of only 118 Å - considerably narrower than any commercially available even at the present time. Another important instrumental development was the seeing monitor” which has since been used to study the statistical variations of the solar seeing and, incorporated into the control systems of the solar telescopes, to obtain improved observations. [11]

Various factors combined to bring about the transition from a small field station near Sydney to the Culgoora Solar Observatory with the CSIRO Division of Radiophysics. The new site has proved very suitable for solar observations, combining long periods of sunny weather, freedom from scattered light, and sufficient periods of good seeing to permit a concentrated attack on those problems of solar physics requiring observations of high spatial resolution.

The major optical instrument at the Culgoora Observatory is a 30 cm refractor designed for high-resolution photography of the sun either in white light or in Hα. Besides a seeing monitor, the telescope incorporates a number of novel techniques to improve image quality developed within the Division; these include air-suction devices to maintain thermal stability near the telescope, and a double-side canopy in place of the familiar dome, which allows the telescope to be operated in thermal equilibrium with its surroundings. Except for the main 30 cm lens (from Grubb Parsons & Co. Ltd, England), all design and construction, including the double supporting tower and housing and the electronic subassemblies, was the responsibility of the Divisions own workshops or of outside contractors in Sydney or Newcastle, New South Wales.

The 30 cm chromospheric telescope is equipped with both a commercial 0.5 Å Halle filter and the Divisions narrow-band 1/8 Å filter mentioned above. The latter filter has now been equipped with computer-controlled tuning: with this arrangement the observer can programme the telescope to take a series of exposures at a number of chosen wavelengths in the Ha line. each sequence of exposures being triggered off by the seeing monitor at moments of atmospheric steadiness. Since its completion in 1967 the 30 cm telescope has been used in a variety of investigations of both the quiet and active chromosphere. The most recent observing programme has been concerned with waves in the chromosphere proceeding outwards from sunspot umbrae and penumbrae. Chromospheric observations with this telescope have attained a spatial resolution of 0.7″ of arc; this figure compares favourably with the theoretical value for a telescope of 30 cm aperture which is 0.55″ at the wavelength of the Hα line.

The second major instrument at Culgoora is the cinemagnetograph which is mounted on a 45 m tower of a different type. The magnetograph is fed by a 20 cm telescope and incorporates a narrow-band filter which consists of a number of Fabry-Perot interferometers working in tandem; the spacing and parallelism of the interferometer plates are maintained by a unique servo system developed in the Division. The films which form output from this installation, after subtraction, display the magnetic field distribution on the sun. The effective spatial resolution at the present time is approximately 3″ of arc.

-Minor instruments at Culgoora include 13 cm. flare patrol telescope which is operated on a daily basis to provide support to the U.S. space programme; it is financed by the U.S. National Oceanic and Atmospheric Administration. By virtue of its longitude, Culgoora is able to play an important part in the worldwide network of observatories supporting such work which is likely to increase in the years ahead. Both the flare patrol and the larger telescopes are expected to take part in supporting NASAs Skylab programme planned for 1973.



For many years the Division has carried out research in the fields of radiative transfer theory and the theory of excitation of spectral lines of interest to solar physicists. Since Dr J. H, Piddington joined the Division in 1967, the Divisions theoretical interests have [12] expanded to include the following topics: magnetohydrodynamical models of the quiet chromosphere; the theory of the 22-year solar cycle and of large-scale motions on the sun; the origin and form of the galactic magnetic field and the origin of cosmic rays; electromagnetic effects of Jupiters satellite Io; density-wave and magnetic theories of the spiral arms of the galaxies and electrodynamical models of radio-galaxies and quasars; and cosmical electrodynamics generally.

In recent years Fellows from Thailand, Japan, France and the United States have worked as Fellows alongside members of the Division. Although so far the fellowship programme has been a modest one, it is hoped to expand this aspect of the Divisions international activities when more powerful and versatile observational equipment has been added to the existing instruments.


THE DEPARTMENT OF PHYSICS IN THE UNIVERSITY OF TASMANIA (Professor G. R. A. Ellis) is engaged in a range of activities in astronomy. Surveys have been made of the sky in the frequency range 2-50 MHz, wavelengths longer than usually used by other radio astronomers. Recent work has included studies of radio bursts from Jupiter and in particular of the dynamic spectra.

X-ray investigations have been made from sounding rockets. Experimental payloads have been developed which are launched when opportunity arises from rockets provided by the U.K. (Skylark) or by NASA (Aerobee and Scout).

An active programme of cosmic ray observations is being carried on and the astronomical implications followed up.

Some investigations have been carried out on pulsars and interstellar medium including pulse characteristics and dispersion. The University is installing a 1 m optical telescope with instrumentation which will give it flexibility for a variety of astronomical work. This will include the physical and chemical characteristics of stars and planets.


THE SCHOOL OF PHYSICS OF THE UNIVERSITY OF SYDNEY has two departments as members of the Cornell-Sydney University Astronomy Centre.

The Chatterton Astronomy Department (Professor R. Hanbury Brown) was established in 1959. The major work of the Department has been the development, construction and operation of the Stellar Intensity Interferometer located at Narrabri Observatory about 500 km northwest of Sydney. The building of the instrument was a joint project of the Universities of Sydney and Manchester (U.K.) and later the Office of Scientific Research of the U.S. Air Force.

The first instruments were made on the bright star Vega in July 1963. Since then the Stellar Interferometer has worked almost continuously. The main observing programme started May 1965, after establishing a completely satisfactory instrument and procedure and ended in February 1972. Before the work began the angular diameters of only six stars were known, all six being giants or supergiants not representative of the main sequence; moreover, the precision of these six measurements, made with Michelsons interferometer in about 1930, is not known. As a result of the work at Narrabri, 32 single stars have been measured, many of them main sequence stars, and the precision and repeatability of these results is well understood.

The interferometer has also been used to develop the technique of intensity interferometry and to explore what could be done with a larger instrument. This work includes the measurement of the size of the emission region surrounding a Wolf Rayet star, the measurement of the distortion of a rapidly spinning star, and observations of the binary star Spica. The work on Spica is of considerable potential value because it shows how, by the use of an interferometer, all the important parameters of a binary star, including the distance, can be found. Other work includes experiments on the effects on an intensity interferometer of atmospheric scintillation and the pulses of light from the night sky due to cosmic rays entering the earth#8217;s atmosphere. Lastly the actual technique of intensity interferometry, in particular the electronic correlator, has been established beyond question.

The work of the interferometer on stars finished satisfactorily in February 1972, and no further work on stars is planned. It was designed to measure stars brighter than magnitude +2.5 and in the range of spectral types and luminosity classes between type 0 and F. The exposure times for stars fainter than +2.5 exceed 100 hours per star; so to add significantly to the work we must increase the sensitivity of the equipment by a substantial amount. New and exciting possibilities require a very much larger instrument some 100 times more sensitive than the present instrument at Narrabri. A detailed proposal was prepared by the Chatterton Astronomy Department and forwarded to the Department of Education and Science in March, 1971. This proposed novel instrument, based on the work at Narrabri, would be capable of measuring stars to magnitude +7.5 and of making a most valuable and original contribution to stellar astronomy. The cost was loosely estimated at about $3 million.

At present the Interferometer is being used, in collaboration with the Smithsonian Astrophysical Observatory in Boston, to look for high energy gamma rays from objects outside the earth. For some years there have been attempts, so far with no certain success, to detect gamma rays by observing the flashes of Cerenkov light made by the rays when they enter the earths atmosphere. Gamma ray astronomy has so far been confined to a few low energy observations from balloons or rockets. Some years ago Cerenkov light pulses were observed using the two reflectors of the interferometer looking simultaneously at the same part of the earths atmosphere where the pulses were generated. This original work was developed by the Smithsonian Institution and now it may well be that the installation at Narrabri is the most sensitive gamma ray telescope in existence. The results of the first programme at Narrabri on gamma rays look promising and possibly the reflectors of the Stellar Interferometer have obtained the first really positive results in a new branch of astronomy, the observation of celestial objects by high-energy gamma rays. The Chatterton Astronomy Department intends to continue this work in collaboration with the Smithsonian Astrophysical Observatory.

A programme of radio astronomy began in 1960 when Professor B. Y. Mills joined the School of Physics with the aim of building a large cross-type radio telescope which was funded in part by the Science Foundation for Physics within the University, but principally by the U.S. National Science Foundation. After design studies, construction began in [15] 1.962 at a site located near Canberra, now the Molonglo Radio Observatory. Observing commenced when the first arm of the cross was completed in 1965, and the whole instrument was put into operation in 1967.

The instrument has two arms each 1.6 km long running east-west and north-south which intersect at their centres. Their width is approximately 12 m, giving a total collecting area of 2 × 104 m2. The east-west arm which is split in the middle to allow the continuous north-south ar a set of pencil beam responses is obtained which produces an image of the small area of sky on the meridian. In addition to this basic system an output from the east-west arm is available at 111.3 MHz and a current design study aims at raising the main operating frequency to near 1,420 MHz within the next few years.

The radio telescope is probably best known for the discovery of many new pulsars, for which the east-west arm is ideally suited. This work has been extended to more accurate timing and positioning of pulsars. The main programmes, however, are concerned with sky surveys, accurate position measurements and the mapping of extended sources and a omplete survey of the southern sky is being made. More than half the available area has been surveyed and the first catalogue of a small area (~0.2 sr) containing 1,500 sources has been prepared. The positional accuracy is typically 10″-15″ arc. Positions with accuracy about 2″ are being achieved for an increasing number of southern sources and optical identifications with these positions are being sought in collaboration with optical observatories and by the use of the Palomar Sky Atlas.

Results of surveys of the Magellanic Clouds and a 6° wide strip along the Galactic plane are being analysed. Studies of individual Hll regions in the Magellanic Clouds have yielded electron densities and masses, while collaboration with Mt Stromlo Observatory has led to the identification of many non-thermal sources with supernova remnants. Analysis of the Galactic survey has provided significant new information about spiral structure and many new Galactic sources which need further investigation.

A recent programme of accurate flux density measurements at 408 MHz to provide suitable calibrating sequences in the southern sky has revealed that many sources are variable at this frequency, an unexpected result with interesting astrophysical consequences.

In a long term programme of planetary observation when circumstances have been favourable it has been possible to measure the 408 MHz emission of Venus, Mars, Jupiter, and Saturn.



THE ELECTRICAL ENGINEERING SCHOOL OF THE UNIVERSITY OF SYDNEY under Professor W. N. Christiansen operates the Fleurs Radio Observatory, 50 km west This observatory was run by the CSIRO from 1954-1962 and from 1963 onward by the University of Sydney. In the earlier period it was the home of several famous radio telescopes known as the Mills Cross (λ = 3.5 m), the Criss-cross (λ = 0.21 m). Parts of the first and third of these telescopes remain as museum pieces, but the second has been rebuilt and now forms part of a new and powerful earth rotational synthesis radio telescope as well as being used as an improved version of the grating cross-in its original form. [16][17 Image]

The new earth-rotational synthesis telescope is a compound interferometer consisting of thirty-two 6 m diameter paraboloids and of two 14 m diameter arranged in a line about 1 km long in an east-west direction. The paraboloids are all fixed in position but can rotate on equatorial axes to follow a source in the sky for many hours. A multichannel radio receiver connected separately to each antenna indicates at any time, 64 sine and 64 cosine Fourier components of the brightness distribution across the radio source under observation. These values are recorded. After 8 hours of observation a sufficient range of scanning angles across the source has been investigated to allow a map of the source to be produced by a computer. A second north-south array, similar to the east-west one, provides a further range of scanning angles and allows sky mapping to be done even at the celestial equator, a thing not possible with other earth rotational synthesis instruments.

The maps produced have a field of 2 square degrees and a resolution of 40 arc seconds at a wavelength of 21 cm. Plans are in hand for a two-fold improvement in this resolution. In addition to being used as a rotational synthesis telescope, the antennas can be connected as a cross to make rapid (1/10 sec.) maps of the sun at a resolution of 3 arc minutes.

Since being brought into operation in the middle of 1972 the synthesis telescope has been used for mapping details of complex sources, mainly in the Galaxy and in the Magellanic Clouds. Polarization measurements are in progress.

A second radio telescope at Fleurs operates at λ = 10 m and consists of an east-west array, one kilometre long and a pair of movable antennas which are used to synthesize a north-south arm. A survey of the sky between declinations −4° and −64° has been completed.

During the last few years work has been done on absolute measurements of sky temperatures by means of horns and scaled arrays.


THE DEPARTMENT OF APPLIED MATHEMATICS ON THE UNIVERSITY OF SYDNEY under Professor K.E. Bullen for some years worked on the internal constitution of the planets as an extension of studies of the interior of the earth derived mainly from seismology.

Now under Professor P. R. Wilson the department has an astrophysics group which initially undertook a theoretical investigation of solutions of the equation of radiative transfer appropriate to inhomogeneous atmospheres, and methods have been developed which are suitable for the analysis of continuum and for line radiation. The most recent development has been the use of the Foutrier technique in the study of inhomogeneous atmospheres in the presence of non-uniform velocity fields. Problems of line formation in magnetic fields are also under investigation.

These methods have been applied to the investigation of a wide variety of solar phenomena. The continuum methods have been applied to sunspots, faculae and the photospheric granulation, while non-L.T.E. spectral line analyses have been used to investigate chromospheric structures.

The group has maintained close relations with the Sacramento Peak and Kitt Peak

Observatories through the Sydney-Boulder Astrophysics Association of which it is a founding member. Several programmes of observations of granulation, sunspots, and structures in the chromospheric lines have been carried out at these observatories and the data have been used in theoretical analyses of these structures. [18]

Currently, attention is being given to sunspot models and the cooling of sunspots, models of the convection zone, study of chromospheric shock waves through the interpretation of Ca II K line data and further theoretical studies of the radiative transfer equation.


THE PHYSICS DEPARTMENT OF THE UNIVERSITY OF QUEENSLAND began research in astrophysics in August 1958. Professor D. Mugglestone developed a method for computing the equivalent widths of weak lines. This was extended by one of his students to include strong lines as well. These techniques were applied to the determination of the solar abundance of several light elements. It was found that for certain spectral lines of sodium and other elements the Stark effect can be the dominant line broadening mechanism. The importance of saturation effects was emphasized. All the calculations at that time were based on the assumption of local thermodynamic equilibrium.

Non-L.T.E. effects in the formation of the strong lines of sodium and calcium were investigated. It was found that the deep cores of these lines are a result of departures from L.T.E. In non-L.T.E. calculations it is usually assumed that scattered line radiation is completely redistributed both in frequency and direction. This assumption was investigated and led to published results on the fundamental problem of redistribution.

During a brief stay Dr G. D. Finn initiated his work on the stochastic theory of radiative transfer. A detailed investigation of the formation of helium lines in 33 main sequence B-type stars uncovered additional evidence of the importance of non-L.T.E. effects. It was found that the triplet lines of helium are sensitive to the U.V. radiation field in these stars. In order to obtain good agreement between theory and observation for the triplet lines it is necessary to include the effects of line blanketing in the ultra-violet. Work carried out on the theory of spectral line broadening has led to a more satisfactory method of dealing with line broadening by collisions with hydrogen and helium; a line broadening mechanism which is very important in the cooler stars.

During 1971 and 1972 the astrophysics group has been host to Dr A. G. Hearn who has been working on radiation pressure driven sound waves in stellar atmospheres, which may provide a possible heating mechanism for chromospheres in hot stars. A systematic method of inverting individual line profiles to obtain information about the physical conditions in the region of the atmosphere in which the line is formed was developed with a student. The method is now being applied to the analysis of high resolution wiggly line spectra of the sodium D-lines and may yield further information on velocity, temperature and density fluctuations in the photosphere.

At present, work is proceeding on the semiclassical theory of radiation and on the redistribution of line radiation, especially in the difficult regime where the collisional width and the natural width of the lines are comparable.

Plans for acquisition of further high resolution wiggly line spectra are under way. The analysis of these spectra to deduce information about solar velocity fields and problems in atomic and molecular physics of astrophysical interest are likely to occupy the group for some time. [19]


THE DEPARTMENT OF MATHEMATICS AT MONASH UNIVERSITY has worked in theoretical astronomy. Professor K. C. Westfold with colleagues has carried out investigations on the circular polarization of synchroton radiation which have been applied to models of the atmosphere of the planet Jupiter. This has led to an investigation of the effects on the frequency spectrum of a truncated energy distribution of the ultra-relativistic electrons contributing to the radiation. The contributions from electrons having small pitch angles are also being studied.

Work in relativistic astrophysics and cosmology carried out by staff members and students in 1972 was concerned with gravitational radiation from black holes and from the collapse of rotating cylindrical systems, with multifluid, anisotropic and scalar-tensor cosmologies and with the examination and classification of exact solutions of Einsteins field equations.

Professor R. Van der Borght and colleagues are investigating the effects of magnetic fields and rotation on finite-amplitude convection, in view of its application to astrophysical problems. Numerical, asymptotic and perturbation methods have been used extensively. A start has been made with the study of compressible and time-dependent systems. Viscoelastic effects and problems in overstability are being investigated.

A theory of supersonic convective turbulence is being developed by Dr A. J. R. Prentice and collaborators to account for the formation of T-Tauri outbursts and the origin of the solar system. It is argued that there may be sufficient energy available during the gravitational collapse of a young proto-star to make the convective motions strongly supersonic. Supersonic turbulent pressure causes the star to appear much more centrally condensed and lowers the central temperature. The protostar comes to quasi-hydrostatic equilibrium near Neptunes orbit and subsequently disposes of its excess angular momentum through the formation of a discrete system of gaseous Laplacian rings. The orbital radii of these rings follow a Titius-Bode law and their masses are each of order 1,000 M⊙ of solar material.

Dr J. J. Monaghan is studying uniformly rotating upper main-sequence stars with internal magnetic fields in an to understand the peculiar A stars. Attention has been directed to stars in equilibrium without circulation. Both axisymmetric stars with multipole fields and non-axis symmetric stars with dipole-like fields are being investigated. The precession and oscillation of the non-axisymmetric model and the effect of vorticity expulsion in rotating stars with no magnetic field are being studied.

Work is being done on the statistical mechanics of fluids by means of a Monte Carlo technique devised so that a range of densities can be treated simultaneously and on transition radiation produced by fast electron-ion encounters.

In 1971 the Department of Chemistry under Professor R. D. Brown turned to the measurement of the spectral lines of cyclic molecules that might occur in interstellar space. This led, in collaboration with the CSIRO Radiophysics Laboratory using the Parkes radio telescope, to the detection of the molecules of thioformaldehyde and formaldimine. Monash has set up a 40 cm reflecting telescope and the Department of Physics has plans for a programme of photometric and spectroscopic studies of stellar atmospheres, in collaboration with the University of Tasmania, and with the Department of Mechanical Engineering for a study of lunar occultations. [20]


THE DEPARTMENT OF PHYSICS OF THE UNIVERSITY OF NEWCASTLE under Professor C. D. Ellyett has for a long time been engaged on work on meteors.

At present this is dene by radar and new equipment has been built for the purpose. This contains highly sophisticated signal processing instrumentation which has been developed in the Department, so that it can now be operated with quite low transmitter power and yet obtain higher meteor rates than were obtained in the radar meteor work over the past two decades. Meteors are being observed as meteoric Es” on a conventional ionosonde to which it is hoped to add signal processing, and by operating in this way, together with 40.68 MHz, to study the duration and time process of meteor trails in the upper atmosphere.


THE DEPARTMENT OF SUPPLY OF THE COMMONWEALTH GOVERNMENT is the chief agent for Australian participation in the space programme. Australias geographic position away from North America and Europe gives an advantage as a location for stations to maintain contact with space vehicles when they would otherwise be out of sight or radio contact. Tracking observations in Australia began during the geophysical year 1957-8 when the mini track facility was installed at Woomera. This was followed by the Baker-Nunn optical tracking camera.

In 1960 an agreement was reached between the Australian and the United States governments for the establishment of space tracking stations in Australia. These have been financed chiefly by NASA. There are now five stations. Mostly these have 26 m diameter antennas. A 64 m antenna is under construction at Tidbinbilla near Canberra. This is similar to the one at Goldstone and to one under construction in Spain. These three will support future space missions which require greater sensitivity or transmitting power. It is anticipated that the 64 m telescope will be available for purely astronomical projects.

Australia also participates in the ELDO programme by providing and operating ground facilities and range instrumental launchings have been made for purposes of vehicle development and the fourth was successful in placing a satellite in orbit. The Skylark high altitude test vehicle can be launched to heights of about 100 miles and has been used for upper atmosphere research as well as astronomical projects. The payloads have been of United Kingdom and Australian origin and include experiments on X-ray astronomy. Currently some thirteen vehicles per year are being launched.

The Department of Supply started balloon flying in a regular way with the establishment of the balloon launching station in Mildura in 1960. At present about ten flights per year are made of which some are being devoted to an infrared mapping survey.Several flights have been made for X-ray astronomy in conjunction with the University of Adelaide and the University of Tasmania. [21]

An encouraging feature of the substantial growth of astronomy in Australia in the past 25 years has been its development in the universities. In 1950 there was no professor or lecturer in astronomy in an Australian university and the basic need for a vital school of astronomy was remarked. Now almost every university is active in astronomy or astrophysics.

The first suggestion that Australia should offer an invitation to the International Astronomical Union to hold an assembly in Australia came from Professor Otto Struve when he was present at a meeting of the Australian National Committee for Astronomy. He was then president of the union. Invitations were issued on several occasions until a later president, Dr P. Swings, indicated in 1966 that the executive would recommend acceptance of the Australian invitation for 1973 to the next executive which, in 1969, approved our outline programme. Now we look forward with keen pleasure to the visit by so many of our colleagues and friends and we hope that they will find their Assembly in Australia pleasant and scientifically profitable. We fully expect that contact with the whole range of astronomical activity will prove a great stimulus to astronomy in our country. [22]

2963 10.72 V. C. N. BLIGHT, GOVERNMENT PRINTER

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