The synthesis telescopes at Fleurs and Molonglo have been used to map 50 supernova remnants. Additional specialized software to process the maps has been developed, and Parkes observations have been used to supply short spacing information missing from the maps.

This review concentrates on observations of neutral hydrogen in the Magellanic System, and what they reveal about the structure, dynamics, evolution and ultimate fate of the LMC and SMC. Some recent observations of 161 Cepheid variables in the SMC are used together with the HI observations to determine the geometry of the SMC. These show that it has an amazing depth of at least 30 kpc. To explain the results it is proposed that the SMC had a close encounter with the LMC which has warped the disk of the LMC, produced the bridge between the two galaxies and tidally fissioned the SMC. The SMC is in the process of irreversible disintegration. It is believed that the Magellanic Clouds are not bound to our Galaxy and approached us from the direction of Andromeda. They may have had a close encounter with Andromeda 3 x 109 years ago, which may explain the massive starburst which occurred in the LMC and SMC at that time. It is believed that the Magellanic Stream has been swept out of the inter-Cloud region by the ram pressure of the gaseous halo of our Galaxy. If dynamic friction is sufficient for the Clouds to be captured and to eventually collide with our Galaxy, a polar ring will be formed similar to that observed in some other galaxies. The polar ring of dwarf spheroidals and outlying globular clusters at present encircling our Galaxy may be the remnants of a previous collision with some other galaxy 6 x 109 years ago.

This review surveys some recent observations of polarization in solar spectral lines with emphasis on their theoretical interpretation. Solar optical polarimetry is concerned primarily with measuring solar magnetic fields, a quest which began with Hale’s (1908) observation of Zeeman splitting in a sunspot. Today a wide range of optical polarimeters is used for solar research (see Bauer (1981) for a comprehensive review). For example, a standard magnetograph (Babcock 1953) detects circular polarization in selected wavelength bands in the wings of a Zeeman sensitive line, providing information on the line of sight or longitudinal field component. The most sophisticated instrument is a Stokes polarimeter (e.g. Bauer et al 1980, 1981) which measures with high spectral resolution the profiles of all four Stokes parameters (I,Q,U,V) across a spectral line. Such a device potentially provides all the data needed to infer the vector magnetic field.

Travelling disturbances in the solar corona with velocities ~103 km/s manifest themselves at radio frequencies by two distinctive phenomena—the type II burst, the spectrum of which shows a slow frequency drift that corresponds to quasi-radial outward motion, and the moving type IV burst, for which positional observations show transverse motion directly. A close relation between the two phenomena has long been suspected, and each type has separately been ascribed to a shock wave disturbance. In this paper we summarize three events recorded by the Culgoora radioheliograph and spectograph (two in the course of publication and one unpublished) in each of which a type II and a moving type IV burst can be consistently attributed to the effects of a common shock wave.

Since the discovery of the first asteroid by Piazzi in 1801, orbits have been determined for over 2500 with varying degrees of quality; 2357 have been assigned permanent numbers as of this writing (Marsden and Bardwell 1981).

The fact that Jupiter’s inner magnetosphere is not axially symmetric was originally demonstrated by ground-based radio measurements. Departures from symmetry are evident in the pattern of bursts occurring at decametre wavelengths and also in the characteristics of the polarized synchrotron emission observed at decimetre wavelengths. Direct measurements of Jupiter’s magnetic field, made from the Pioneer space probes, also indicate departures from an axially symmetric configuration.

The Logo of the Australia Telescope National Facility (ATNF) depicts a linear array of six antennas in the Southern Hemisphere. Precision measurement of this image implies that the Compact Array is located at latitude 37° south and azimuth 176°; this corresponds (surprisingly) to an approximately north-south array. Furthermore, the ATNF Logo was apparently prepared at LST 04h 00m.

The literature contains numerous predictions of an X-ray pulse associated with the emergence of the shock-wave at the surface of a star undergoing a supernova explosion. Applied to supernova 1987a, these suggest a small, solar-flare like event lasting about a minute with a terrestrial flux of order 1 μ Wm-2 and a black-body temperature between 106K and 107K occurring between 0900 and 1000 UT on February 23, 1987. Unfortunately, no direct X-ray observations appear to have been made. However, such an event would be expected to give rise to an observable enhancement of ionization in the upper D-region of the ionosphere. The absence of a detectable perturbation in VLF radio signals propagating in the earth-ionosphere waveguide sets upper limits to the X-ray flux and temperature below those predicted.

The survey techniques for finding quasars in large areas of sky have developed rapidly in recent years. One can search for quasars in all wavelengths. The area of sky surveyed may be more than 1000 square degrees. The average density of quasar candidates down to magnitude 20 is about 20 per square degree. Therefore, more than 20 000 quasar candidates are waiting for further observation. The total number of confirmed quasars is currently about 5000. This paper gives a discussion of some of the physical properties of quasars, such as space distribution, luminosity function, clustering and redshift limit.

Both radial and non-radial motions have been suggested at various stages to explain the observational peculiarities of the β Cephei variables. The non-radial possibility has been investigated most recently by Smith (1977) and Stamford and Watson (1977). We here examine the radial shock proposal by generating a series of isothermal radial shock models in suitable early B star atmospheres. Odgers (1955) has long advocated such a model in connection with the large amplitude variable BW Vul. The observations of Goldberg, Walker and Odgers (1976) clearly show a radial velocity ‘stillstand’ effect and line splitting in this star. We discuss our models in the context of these two phenomena.

Model calculations for the photospheres of SN 1987A are presented. Spherical symmetry and density profiles are assumed to be given by the homologous expansion of the stellar structure of a B3I supergiant. For later stages the density slopes are determined. For a number of elements (H, He, C, N, O, Ne, Na, Mg, K, Ca, Ba) detailed atomic models are used. The statistical equations and the radiation transport are treated consistently as well for the lines as for the continua. In addition, line blanketing due to other elements are included under the assumption of pure scattering. The importance of a sophisticated NLTE-treatment is demonstrated. Chemical metal abundances are derived by comparing the observed and synthetic spectra. Good agreement is found if a third of solar abundance for all elements with the exception of the s-process elements is assumed. An overabundance of He by a factor of 1-2 is indicated by the models corresponding to the time before June 87. No gradient in the chemical abundances of the hydrogen rich layers has to be assumed. Up to October 87 the He abundance at the photosphere is increased to 5 times solar, i.e. the continua are formed in helium rich layers. The chemical profile indicates strong mixing processes of the different layers of the progenitor during the explosion. Additionally, pecularities of hydrogen line profiles are discussed. Mainly, they can be understood by selective line blanketing effects. The total mass of the hydrogen rich shell is estimated to amount to be 9-11 M⊙.

We present a survey at J (1.25μm) and K (2.2μm) of 36 arcmin2 in the Bar and Inner Wing of the Small Magellanic Cloud. The (J-K) colour – bolometric magnitude diagram is constructed and compared with theory. For the first time a sparsely populated region of the diagram separating proposed carbon stars from oxygen rich stars has been identified. In addition large numbers of red sources have been found apparently fainter than the accepted limit for carbon star formation. These include extremely red sources which are good candidates for OH/IR sources and extreme carbon stars.

We have extended the integration time of a Philips type 56470 video camera to make it useful for visual offset guiding on 0.6- and 1-metre telescopes.

This paper discusses the accretion wave phenomenon as a generator of the Great Galactic Ring and the mechanism for forming discontinuities in interstellar gas flows.

This communication describes techniques, new to radio astronomy, which permit the analysis of electrical signals at radio-frequencies by optical methods.

Two applications will be described: the first is to a spectrograph which gives the instantaneous power spectrum of a single broad-band electrical signal; the second is to the analysis of the signals from a number of aerials of an array in order to form a simultaneous image of the brightness distribution of the region of the sky under observation.

As the night sky near Canberra grows brighter each year, many of the traditional areas of investigation at Mount Stromlo are suffering, and work in these fields is shifting to Siding Spring Mountain, near Coonabarabran, N.S.W. One of several projects designed to ensure the continued productivity of the 74-inch reflector at Mount Stromlo as conditions change has been the installation of an échelle grating system in the coudé focus of the telescope. This will allow very high dispersion work on bright stars, and should be littles affected by nearby city lights.