The role of astronomy in the cultural exchanges between India and China through several centuries is taken as an example of astronomy shaping human life. Then the tradition of astronomy in the development of scientific thought is examined. The contribution of astronomy in shaping the post-Renaissance society is briefly introduced. It is concluded that the recent developments of ideas in cosmology throw light on the intrinsic nature and limitations of the scientist as a human being.

A few days ago a prominent physicist, Professor Frank Stacey of the University of Queensland, made a public statement on his retirement that he was burying a theory. He had believed he had measured a new gravitational constant for close objects. Over 12 years he and colleagues in Australia and overseas had tried to confirm a theory of a fifth fundamental force of nature to explain the observations. His claim had gained a great deal of publicity as, if true, it would have extended Newton’s law of gravity and Einstein’s theory of general relativity.

We have undertaken a study of the 3-D spatial distribution of the older (τ ≥ 1–2 Gyr) stellar population lying beyond ~ 2 kpc in projected radial distance from the centre of the SMC. The study will eventually cover 120 square degrees including six overlapping Schmidt fields. Here we present the results from an area of 80 square degrees including the western, northern and north-eastern outer parts of the SMC.

This paper presents a brief discussion of the apparent underdepletion of the heavy neutron-capture elements (elements heavier than Ba), compared with Fe in the Magellanic Clouds. The s-process appears to have been only effective in forming elements in the light neutron-capture group (Sr, Y, Zr) in the Magellanic Clouds, but to have much reduced effectiveness in forming the heavy neutron-capture group. The abundances of the elements heavier than Ba have a distribution that indicates that they were produced by the r-process alone.

The Perth Astronomy Research Group (PARG), consisting of members from Curtin University of Technology, Perth Observatory and the University of Western Australia, is in the process of developing an automated supernova search system, using the 61-cm Lowell-Perth reflector, a CCD camera and an 80386-based computer for image analysis. Computer control of the telescope and dome, a liquid-nitrogen-cooled CCD camera, and modified VISTA image analysis software will be completed in late 1990, allowing initial semi-automatic searching of external galaxies, together with CCD photometry of flare stars and newly discovered supernovae. Full-scale automation will be introduced subsequently, in collaboration with the Berkeley group. This paper describes the project, and reports on its current status.

In order to find the best observable diagnostics for the amount of internal extinction within spiral galaxies, we have constructed models for disk galaxies with immersed dust layers. The radiative transfer problem, including both scattering and pure absorption, has been computed for a range of model galaxies. This reveals a set of superior diagnostics for the opacity. These include the behaviour of the radial colour and luminosity distributions, the amplitude of the asymmetry between the near and far sides of the major axis, and their dependence on the orientation of the galaxy with respect to the observer.

Some initial results of a flux-calibrated CCD Hα imaging program of bright, nearby southern spiral galaxies are presented. Very few southern hemisphere spiral galaxies have ever been completely imaged in Hα, let alone with a CCD. This survey (which mainly uses the MSSSO 1.0-m reflector with an f/3.5 focal reducer) will, when combined with spectrophotometry of the H II regions thus revealed, allow us to trace the chemical evolution of each galaxy. Furthermore, since the absolute Hα flux is a reliable measure of the high-mass star formation rate in a galaxy, such observational data will permit us to test the predictions of the various star formation theories.

We examine the nature of the redshifts of twin quasars with discrepant redshifts (θ < 100 arcsec, Δz ≥ 0.5) by considering their Hubble diagram. If such twins are physically associated one expects a large scatter in their Hubble diagram. However, we find a statistically significant linear correlation between log (cz) and Vc magnitudes of such quasars, consistent with the hypothesis that their redshifts are cosmological in nature.

This paper examines recent investigations of emission-line filaments along the edge of the radio source in Centaurus A. It shows how these studies have ramifications for the excitation of the narrow line regions and extended emission-line regions of other active galaxies.

Global magnetic structure has been inferred in spiral galaxies from radio and optical observations. The author has developed a three dimensional, quasi-global kinematic dynamo model which demonstrates the possibility of maintaining large-scale magnetic fields by the αω mechanism. Analytical expressions for large-scale galactic magnetic fields near temporal steady states have been derived. Illustrations of the spatial distribution of vector and absolute large-scale magnetic field strength are presented. When coupled with observations this model may help in understanding the maintenance and morphologies inferred for disk and halo global magnetic fields in spiral galaxies.

Four examples of dwarf galaxies apparently undergoing mass loss are discussed. All have an Hα morphology suggesting a minor axis flow. This is supported by velocity field measurements in three cases. All also have at least one compact central object, probably a young star cluster, apparently powering the flow. Some implications of these results are briefly discussed.

Using a complete sample, we have looked for correlations in position between radio sources with S408 ≥ 1 Jy in the Molonglo Reference Catalogue (MRC) and rich clusters of galaxies in the Abell, Corwin and Olowin catalogue (ACO). Within a projected radius of 100 kpc of the cluster centre, we find an overdensity of radio sources similar to that seen by Robertson and Roach (1990). They attributed this feature to centrally located dominant cluster galaxies. We confirm this hypothesis by looking at the morphology of the clusters within this peak and by optically identifying galaxies associated with the radio emission. Due to the relatively high flux density limit imposed, the cluster radio sources in this sample are among the most powerful in the southern sky. The probability of a cluster containing a radio source of this power is found not to depend on cluster richness.

Young supernova remnants are poorly understood and few are known. Further examples may be present, but unrecognised, within existing catalogues of radio sources. G274.68–2.84 was recently suggested as one such candidate but our new radio map from the Australia Telescope indicates that it is not a supernova remnant. Rather, it appears to be extragalactic with a strong, variable, flat-spectrum nucleus, and a bright X-ray counterpart.

The changing total luminosity of SN 1987A between 2 and 1200 days after core collapse is illustrated and discussed. From about four weeks after outburst the supernova light curve was dominated by the release of radioactive decay energy; the major contributor being 0.078M⊙ of 56Co. Recently an additional contribution probably from the decay of 57Co and 44Ti appears to be manifesting itself in the light curve. A gradually increasing fraction of the radioactive decay energy has probably been emitted at X- and γ-ray wavelengths; the fluxes are low and no recent measurements have been published. Most of the remaining radioactive decay energy appears to be emitted in the IR and is very difficult to measure. Other factors influencing the interpretation of the recent light curve are the uncertain contribution from long-lived radioactive isotopes and light-echoes. It is therefore premature to make any definitive statements on the contribution from the neutron star, although it is probably less than a few times 1037 erg s−1.

This paper summarises Ginga X-ray observations of SN 1987 A.

The prompt radio emission associated with SN 1987A appeared and disappeared within the space of a few days. The next radio emission is expected as the high velocity ejecta expand into the circumstellar material. The evidence from the timing of the initial UV-flash is that this stage may occur shortly. We have therefore begun to monitor the field around SNR 1987A at high sensitivity with the Australia Telescope Compact Array. At λ6cm, an upper limit to the radio emission of 180μJy has been obtained. Continued observations are planned.

This paper presents a brief discussion of the AAT data on SN 1987A and its archive.

A China-Japan X-ray balloon flight took place in 1988 August. Preliminary results are presented for the energy spectrum of Cyg X-1.

Air showers initiated by primary cosmic rays and gamma rays produce shower fronts which are curved. However, the arrival directions of air shower events have normally been fitted assuming a planar shower front. We present a technique which takes the average shower front shape into account to assign an improved shower direction after a first analysis assuming a plane front. We then examine the resulting angular resolution of the Buckland Park array.

We examine the production of cosmic ray positrons by photon-photon pair production of high-energy γ-rays on starlight photons. We start by calculating the production rate as a function of positron energy and distance from the Sun resulting from interactions with sunlight. The results are generalized to production on other types of star. We calculate the average production rate per unit volume averaged over the local region of the galaxy, and we estimate the contribution to the observed intensity from this process.