There is a need for standardised terminology in the field of astronomy. A project on behalf of the International Astronomical Union has been undertaken by astronomy librarians to compile a thesaurus for inputting to and accessing computer database systems.

We present 6 cm Australia Telescope images of 22 strong southern radio sources. At least one of these sources appears likely to be a gravitationally lensed mirage.

This paper describes the plans for a planetarium and observatory at Sydney’s Macquarie University.

It is impossible in half an hour to do justice to the vast literature on Shockwaves in interstellar space. Here, an attempt is made to identify outstanding problems with particular regard to the optical spectrum and to determine what physical data can be relatively unambiguously obtained from interpretation of this.

The Orion Nebula is the best known and most often observed of the bright emission nebulae. However, the radio continuum spectrum of the nebula has been the subject of some misconception, particularly at low frequencies. A rediscussion is worthwhile as the spectrum has been used to derive an electron temperature for the nebula which is at variance with other determinations and carries important implications. Also some of the difficulties of measurement and problems of interpretation are relevant to similar investigations of other emission nebulae.

This paper outlines the plans for a Japanese lunar exploration mission in the mid-1990s.

Symbiotic stars are at the same time perplexing and rewarding to study. Their spectra contain great numbers of emission lines due to atoms in a range of ionization states from neutral to coronal. The continua are weak and usually unobtrusive: the strongest lines may have equivalent widths of thousands of Angstroms. But the crowding of weak lines complicates their measurement and, often, their identification. Many symbiotic stars probably emit weak lines which currently defy identification, but which cannot be distinguished from their neighbours. It is, however, rather rare to find a strong unidentified emission line.

The dry, cold, tenuous and stable air above the Antarctic Plateau provides superb conditions for the conduct of many classes of astronomical observations. We review in particular the rationale for undertaking near-IR, mm and particle astronomy in Antarctica, disciplines where telescopes are now operating at the US Amundsen-Scott South Pole Station.

Spectroscopic observations of BF Cygni performed at the Haute-Provence Observatory in 1981 August, October and November are presented. The spectrum of BF Cyg was dominated by strong emission lines of H I, He I, [O III] and [Ne III]. Emission lines of He II and N III were weak. The spectrum of the star displayed dramatic variations during our observations. The intensities of Balmer lines, Balmer continuum and He I lines clearly increased from August to October, while the lines of [Ne III] and [O III] showed inverse variability.

We discuss the basic concept and the problems of magnetic braking via magnetically controlled hot plasmas in late-type stars. We investigate the magnetic braking process in special magnetic field structures in both single stars and binaries. We find that in single solar-type stars, the high-order component of the observed complicated fields can account for the braking rate of the present Sun. However, this component cannot account for the braking rate of young solar-type stars, even though this field is much stronger than the simple (monopolar or dipolar) field usually adopted in braking models. For magnetically interacting cataclysmic binaries, the magnetic fields of the white dwarf greatly change the magnetic fields on the main-sequence secondaries. In particular, in synchronously rotating magnetic CVs (AM Herculis systems) magnetic braking may even turn off if the white dwarf magnetic field is sufficiently strong. These results suggest that the magnetic field structure has a crucial effect on magnetic braking.

According to Dyson (1960), Malthusian pressures may have led extra-terrestrial civilizations to utilize significant fractions of the energy output from their stars or the total amount of matter in their planetary systems in their search for living space. This would have been achieved by constructing from a large number of independently orbiting colonies, an artificial biosphere surrounding their star. Biospheres of this nature are known as Dyson spheres. If enough matter is available to construct an optically thick Dyson sphere the result of such astroengineering activity, as far as observations from the earth are concerned, would be a point source of infra-red radiation which peaks in the 10 micron range. If not enough matter is available to completely block the stars’ light the result would be anomalous infra-red emission accompanying the visible radiation (Dyson 1960).

The standard formula for the resolving power R(= λ/Δλ) of an astronomical grating spectrograph isHere L is the linear size of the grating, perpendicular to the direction of the grooves, θB is the blaze angle of the grating, θS is the angular size of the slit, projected back on to the sky, and D is the diameter of the telescope objective. The formula is valid for gratings used in the Littrow condition, when the angle of incidence α, and the angle of diffraction β, are both close to θB .

Optical spectra of pre-main sequence flare stars in Orion are presented and analysed by the use of stellar chromospheric models. The stars observed divide into three groups on the basis of their quiescent spectra. The majority of the sample are similar to the dMe stars, with prominent Ca II and Balmer line emission. A second group possesses very strong emission spectra, including He I lines. Stars in third group, however, show little or no emission spectrum. Amongst the emission line stars observed progressively brighter stars exhibit increased Ca II and Balmer line surface fluxes relative to the fainter stars. This trend is also exhibited as a rise in emission line surface fluxes with increasing effective temperature. To analyse this trend a set of non-LTE stellar models were calculated. Using this analysis the trend in line fluxes between stars of different brightness and temperature is interpreted as a spread in the level of chromospheric heating. Furthermore, this trend is interpreted as indicating a spread in the effectiveness of the stellar magnetic dynamos within these stars, perhaps arising from shallowing in their convective layers as they contract to the main sequence.

Sir William Herschel and his sister, Caroline, had swept the skies over England as members of the court of George III. They had made amazing discoveries: a new planet in our solar system, the movement of the solar system with respect to the fixed stars, and hundreds of new nebulae and star clusters.

Then Sir William’s son John swept the southern skies from Cape Town, South Africa (1834 to 1838), mapping and sketching many more stars and nebulae.

The availability of Magellan radar images of Venus on CDROM allows small research groups to engage in planetary physics projects using simple image processing systems. The material lends itself to short projects for high school students or Masters students.

Our initial investigations using the Magellan data have evolved into a Masters project which concentrates on the morphology of small scale structures which have terrestrial counterparts. These include studies of volcanic cone fields, lava tubes and other collapse features, and impact features.

Truncated modal expansions have provided a powerful, reasonably accurate and flexible approach to the problem of non-linear thermal convection. They permit tractable numerical solutions of three-dimensional cellular motions, as well as readily accommodating large density variations, time dependence, rotation and magnetic fields.

It is well known that the satellite systems of the major planets Jupiter, Saturn and Uranus share many of the same regular features that can be seen in the planetary system of the Sun. The inner satellite orbits are nearly circular and lie in the plane defined by the axis of rotation of the central body. Again the distances Rn of the regular satellites, numbered inwards to the centre n = 0, 1, 2, …, form a nearly geometric sequence

R n/R n + 1 ≌ constant,

similar to the Titius-Bode law of planetary distances. These facts suggest that the same cosmogonic process must have been responsible for the origin of both types of systems.

Radio snapshot imaging is an efficient observing method which allows several sources to be observed in the one session. Snapshot observing with the Australia Telescope Compact Array (ATCA) involves special difficulties, as the small number of antennas combined with the short total integration time leads to high sidelobe levels in the raw images. The images can be improved markedly by standard deconvolution techniques, but more care is required in their use because of the difficulty in distinguishing real emission from artefacts. This study, based on a set of snapshot observations of strong sources at 5 GHz, gives guidance on both the planning of observations and the data reduction. We show that snapshot imaging with the 6 km ATCA can achieve a dynamic range of 100–200:1 provided certain conditions are met, namely a peak flux density > 100 mJy, an angular size ≤ 30″ and an hour-angle coverage spanning at least six well-separated 5-minute cuts. When observing weak sources it is essential for calibration sources to be selected carefully and observed frequently.

It is well established (e.g. Slee et al. 1983) that radio galaxies near the centres of rich clusters of galaxies tend to have steeper radio spectra than field radio galaxies. The fact that the sources with the steepest spectra occur in clusters that are highly luminous X-ray emitters has generally been interpreted in terms of the confining influence of a hot (~108 K), relatively dense (10-2 to 10-3 electrons cm-3) intra-cluster gas; the confined relativistic plasma then preferentially loses its high-energy electrons through synchrotron and inverse Compton losses, resulting in a steepening of the radio spectrum. A more detailed review of the evidence for this process is given by Robertson (1983).