Construction of the Pierre Auger Observatory for the study of the highest-energy cosmic rays is about to begin. Prior to the availability of data from that experiment, decisions should be made on techniques for the analysis of the directional properties of those data. We examine here one possible analysis tool, the two-point angular autocorrelation function. As a concrete example, data from the SUGAR array are examined in this way. Possible clustering of the data is observed, and the identification of such clustering with candidate astronomical objects in a purpose-developed catalogue is investigated.

There is now evidence that there may be a strong source of cosmic ray particles in the general direction of the Galactic Centre. The likelihood is that the observed particles are neutrons with energies of about 1018 eV. Associated with the production of those neutrons, we would expect that large numbers of charged cosmic rays would also be produced, and we investigate here the directional properties of those charged particles as they may be observed at the distance of the Earth from the Galactic Centre. We follow the propagation of such particles through a simple Galactic magnetic field model with both a turbulent and a regular field to determine what field properties most affect the observed beam. It appears that the turbulent field component is crucial to any resulting charged particle observations.

Redshift surveys constitute one of the prime tools of observational cosmology. Imaging surveys of the whole sky are now available at a wide range of wavelengths, and provide a basis for the new generation of massive redshift surveys currently in progress. The very large datasets produced by these surveys call for new and sophisticated approaches to the analysis of large-scale structure and the galaxy population. These issues, and some preliminary results from the new redshift surveys, were discussed at the second Coral Sea Cosmology Conference, held at Dunk Island on 24–28 August 1999. This is a summary of the conference; the full conference proceedings are on the WWW at http://www.mso.anu.edu.au/DunkIsland/Proceedings.

The E. & F. White Conference held in Sydney in December 1999 brought together expertise on a range of interference mitigation techniques from CSIRO, Australian and international industry and universities. Key goals were to enhance the understanding of techniques and their inter-relationship, to increase awareness of advanced technologies such as software radios and photonics, and to foster a cooperative approach to the development of interference mitigation techniques. The foremost application in mind was the square kilometre array (SKA) and the need to find ways to develop a hierarchical scheme for removing unwanted signals from astronomical data. This paper gives an overview of the topics discussed at the conference and summarises some of the key ideas and results that were presented.

We describe a population of compact objects in the centre of the Fornax Cluster which were discovered as part of our 2dF Fornax Spectroscopic Survey. These objects have spectra typical of old stellar systems, but are unresolved on photographic sky survey plates. They have absolute magnitudes −13 < MB < −11, so they are 10 times more luminous than any Galactic globular clusters, but fainter than any known compact dwarf galaxies. These objects are all within 30 arcminutes of the central galaxy of the cluster, NGC 1399, but are distributed over larger radii than the globular cluster system of that galaxy. We suggest that these objects are either super-massive star clusters (intra-cluster globular clusters or tidally stripped nuclei of dwarf galaxies) or a new type of low-luminosity, compact elliptical dwarf (‘M32-type”) galaxy. The best way to test these hypotheses will be to obtain high-resolution imaging and high-dispersion spectroscopy to determine their structures and mass-to-light ratios. This will allow us to compare them to known compact objects and establish whether they represent a new class of hitherto unknown stellar system.

We have analysed the 2dF spectra of a sample of galaxies common to the 2dF Galaxy Redshift Survey (2dFGRS, Colless 1999) and the NRAO VLA Sky Survey (NVSS, Condon et al. 1998). Our sample comprises 88 galaxies selected by Sadler et al. (1999) from 30 2dFGRS fields observed in 1998. In this paper we discuss how this and future, much larger, samples of 2dFGRS–NVSS galaxies can be interpreted via analysis of those galaxies with strong narrow emission lines. Using diagnostic line ratio measurements, we confirm the majority of the eyeball classifications of Sadler et al. (1999), although many galaxies show evidence of being ‘composite’ galaxies—mixtures of AGN plus starburst components.

Variable absorption features were observed in the visible and ultraviolet spectrum of β Pictoris soon after this star gained attention in the early 1980s due to its large IRAS infrared excess and the discovery, from optical imaging, of an edge-on dust disk. The absorption has been attributed to the evaporation of infalling planetesimals or comet-like bodies (the falling evaporating bodies, or FEB, hypothesis). With a view to confronting this hypothesis with fuller observations, we monitored the Ca II H and K lines in β Pictoris simultaneously during 1998, obtaining sequences of spectra on 50 nights. Variable absorption was usually present. The different oscillator strengths of the H and K lines permit the determination of covering factors, but detailed modelling is required to test whether all features can be explained by the FEB hypothesis. The blend of Ca II H with Balmer H ε means that the H and K photospheric profiles are different, and that the variable absorption features do not evolve in parallel. The behaviour of the variable absorption on November 27 is evocative of a body passing in front of the stellar disk in a prograde equatorial orbit.

We discuss variations of the atmospheric extinction coefficients and transformation equations to the standard UBVRI system based on observations of standard stars during 1996–1997 at Siding Spring Observatory using a thinned SITe CCD and coloured glass filters. In the transformation from the initial natural system to the Landolt version of the standard system, a large nonlinear term related to the Balmer discontinuity was required for the U transformation. We then modified the U filter, and the subsequent transformation to the SAAO version of the standard UBVRI system had only small nonlinear correction terms for U, B, and I. The correction terms relating to U and B are evidently due to the Balmer discontinuity, while that relating to I seems to be due to the Paschen discontinuity at λ ≈ 8200 Å. We also compared the results with Landolt's observations, and confirmed the difference between the two sets of standard stars (SAAO and Landolt).

The Antarctic Plateau provides the best terrestrial sites for infrared (IR) and submillimetre (sub-mm) astronomy. In this paper we examine the relative importance of temperature, aerosol content and precipitable water vapour to determine which parameters have the greatest influence on atmospheric transmission and sky brightness. We use the atmospheric modelling program MODTRAN to model the observed sky spectrum at the South Pole from the near-IR to the sub-mm. We find that temperature and aerosol content determine the quality of near-IR observing conditions, aerosol content is the determining factor in the mid-IR up to 20 μm, while at longer wavelengths, including the sub-mm, it is the water vapour content that matters. Finding a location where aerosol levels are minimised is a key constraint in determining the optimum site on the Antarctic Plateau for an IR observatory.

Infrared astronomy has made remarkable progress over the past quarter century. This paper, which is a brief summary of the 1999 Ellery Lecture, outlines the importance of the infrared, traces some of the key Australian developments in the field, and looks ahead to the challenges facing infrared astronomers in the immediate future.

In recent years, formal astronomy education has become an issue of great interest. Indeed, some boards of education now officially include astronomy in their curricula. While formal astronomy education continues to gain attention, informal astronomy education for the general public has rarely been addressed. One valuable source of informal astronomy education is the observatory ‘visitor centre’. Observatories draw thousands of visitors each year, and as such represent a golden opportunity for the astronomical community to communicate directly with the public. This paper summarises an exploratory study of the cognitive and affective impacts of a visit to the visitor centres located at Mount Stromlo and Siding Spring Observatories.