The influence of the progenitor’s stellar wind on the supernova event, and subsequent development of a remnant are discussed. Various morphological differences between SN remnants and the implications for previous wind activity are described. A detailed look at the effects in the ring nebula NGC 6888 is presented.

Many authors (e.g. Magun et al. 1975) have debated the question ‘does solar type IV continuum emission arise through Langmuir wave conversion or through gyro-synchrotron emission?’ Culgoora radio spectrograph and heliograph observations of the late stages of a recent (7 September 1977) type II, IV event showed both type IV* (continuum) and transient type III (electron-beam) emission coming from the same source, high above the solar limb. These observations suggest that this particular type IV continuum arose through a mechanism similar to that of the type III, probably fundamental Langmuir-wave emission, in a corona with a tenfold enhancement of plasma density.

The thermal emission from a cold, dense molecular cloud peaks in the far IR, and the spectrum is rich in molecular lines in the submillimetre and millimetre bands. Observation of these bands is hindered, however, by atmospheric water vapour, which absorbs the incoming radiation. Ground-based mm observations from Australia, where the atmospheric water vapour content typically contains ~10 mm precipitable (ppt) H2O, can only probe a few of the molecular transitions from the heavier molecules, such as CO, CS, HCO+ and HCN. Sub-mm observations would enable the higher rotational lines from many of these molecules to be studied, and open up other spectral features to scrutiny, such as the lines from hydrides (e.g. CaH, NH, SH) and neutral carbon at 370 and 610 μm. However, they cannot be made from Australia. While sites such as Mauna Kea, which has ~1 mm ppt H2O on the best days, open the sub-mm band to partial viewing, their utility is limited in comparison to the opportunities possible from the Antarctic Plateau. Here the column of H2O drops to 100–250 μm.

A natural introduction to this topic is a brief discussion of two phenomena observable in interplanetary space near Earth—the energetic storm particle event (ESPE), and the recurrent Forbush decrease.

The processes of accretion onto the white dwarf in a cataclysmic variable are reviewed. These systems provide the most easily observable examples of accretion disks, and enable the structure of the accretion region to be studied in detail. The properties of column accretion onto magnetic cataclysmic variables are also described.

In November 1975 workers at the Herzberg Institute for Astrophysics in Canada (Avery et al. 1976) discovered cyanodiacetylene in Sgr B2. This molecule is the heaviest yet detected in interstellar space, having a molecular weight of 75 amu, and is the longest linear molecule known.

A program to determine accurate radio positions and optical identifications of southern flat-spectrum radio sources has been undertaken with the six-dish array of the Fleurs synthesis telescope at 1.4 GHz and using the SERC J sky survey. This sample covers the declination range −80° to −50° and comprises all 198 sources from the Parkes catalogue with α of > −0.5 and flux density of 0.25 Jy.

The radio astrometric phase of the program is complete. We conclude that by comparison with accurate VLBI positions the FST positions have r.m.s. uncertainties of ∼0″.9. There is no global bias in the FST positions at the 0″.2 to 0″.3 level relative to the JPL VLBI extragalactic reference frame. A comparison with positions from the Parkes catalogue shows that in the southern regions the Parkes catalogue has rms position errors of about 9″. There is no significant bias between the FST and Parkes positions.

The adjective ‘high’ when applied to the resolving power of radiotelescopes, has a meaning that has changed very rapidly during the last twenty-five years. In the late 1940s a resolving power of one degree was considered to be ‘high’.

The accepted interpretation of the low frequency turnovers in the spectra of many extragalactic radio sources is that they are due to the effects of synchrotron self-absorption, i.e. to the source becoming optically thick. It has been shown that the signs of the degrees of both linear and circular polarization for a homogeneous source at frequencies where it is optically thick are opposite to those at frequencies where it is optically thin.

The radio object associated with Sco X—1 noted by Andrew and Purton has been observed at a wavelength of 6 cm with the 210 ft radio telescope at the Australian National Radio Observatory, Parkes. At this wavelength the half-power antenna beamwidth is 4′ arc.

The Universities of Adelaide and Tasmania (UAT) have now collaborated in the preparation of four experiments on British Skylark rockets. Two independent X-ray detectors of total sensitive area 40 cm2 were flown on each of two rocket flights launched in April, 1967. The most significant result of these measurements was the discovery of Cen XR-2 and the measurement of the variation in its intensity and spectrum. The third flight, launched in December 1967, carried three X-ray detectors of total area 140 cm2. One of the main results from this flight, evidence for a new X-ray source at high galactic latitude, will be presented in the following paper.

Thirty-one radio sources have been investigated for the presence of OH-line radiation in their directions. Absorption and anomalous emission lines were observed.

The equipment and methods of observation have been described by Gardner, McGee and Robinson (1967). An aerial beamwidth of 12’.5 arc was combined with a 48-channel line receiver of bandwidths 37 and 10 kHz.

It has been suggested (Holman et al 1980; Melrose and Dulk 1982a) that solar microwave spike bursts are due to electron cyclotron maser action. These bursts have been observed in the range 1-3 Ghz, and occur in conjunction with flare-associated impulsive microwave and hard X-ray bursts. The bursts have rise times of a millisecond or less (e.g. Slottje 1978).

There are two current models for the typical radio spectra of flare stars, which have a broad peak around a frequency typically 1 – 10 GHz. One model involves both optically thick and optically thin emission, with the turnover attributed to the source becoming self-absorbed. The other model involves only emission at optical depth unity, so that observing different frequencies corresponds to ‘seeing’ different regions in the source. The two models are reviewed, and new calculations for an inhomogeneous source presented.

A proposal for the siting of additional 14 metre antennas for the Fleurs Synthesis Telescope (FST) was previously presented by Christiansen (1976). Since that time, difficulties have arisen which preclude the use of two of the locations. In addition, solutions to the problems of data reduction for irregular antenna spacings have been found (Frater and Skellern, 1978; Frater, 1978; Frater, 1979). It has now been possible to choose the locations of the final antennas to optimise the performance of the array within broader geographic constraints — subject now to the availability of sites on ‘friendly’ land.

It has become recognized that the dominant mechanism in the formation of the cores of resonance lines in the solar spectrum is non-coherent scattering, e.g., Thomas (1957). A study, preliminary to the theoretical investigation of the spectra of chromospheric structures, is the evaluation of the effect of diffuse reflection and transmission by non-coherently scattering media.

The Sun being a highly ionized gas, the basic physical quantities most needed for understanding solar phenomena are temperature, pressure (or density), velocity and magnetic field, together with their variations in space and time. The general aim at Culgoora is to secure observations from which these quantities may be derived (insofar as is practicable) simultaneously over extended solar regions. To do this has involved the development and use of filters of high spectral and spatial resolution, the study of atmospheric seeing and ways of securing high-resolution observations, and the study of methods of analysing observations to yield the physical quantities needed.