This paper gives a short description and interpretation of some solar magneto-hydrodynamical and plasma phenomena, based mainly on work by the writer and his collaborators (for an extended review see Kaplan et al. 1974).

The magnetic field is considered as the main factor responsible for a number of manifestations of solar activity. At the photospheric level active regions are displayed as plages, i.e., bright areas, seen near the limb. This means that the temperature gradient in plages is smaller than in the undisturbed photosphere. The decrease in gradient is a result of an increase of convective transport of energy.

‘History is Bunk’ said Henry Ford. He was exaggerating but it is well recognized that the connection between history and truth is tenuous. Even very recent history dependent on human memory is notoriously unreliable despite the intention of the historian to tell the truth.

In radio astronomy we are fortunate in having a dedicated historian-astronomer by the name of Woody Sullivan who has spent years in interviewing and reinterviewing astronomers to find out the real facts about the early years of the subject. Because of Sullivan’s work (e.g. Sullivan 1988) and because so many of my former colleagues have written histories of the period I felt very doubtful about adding my piece to the saga when asked to do so. However, I did accept the invitation to do so after I had read a statement about radio astronomy written by our usually very well informed Minister for Science, Barry Jones (Jones 1987). This statement which I shall quote later is an example of what we may call popular history.

The magnetic field and orbital period distributions of AM Herculis binaries are investigated. Our study shows that (i) there is a significant lack of very-high-field magnetic white dwarfs in binaries when compared with isolated white dwarfs, and (ii) the difference between the period distributions of AM Herculis binaries and other cataclysmic variable subclasses is statistically significant. These results imply that the evolution and the birth of AM Herculis binaries are different from those of other cataclysmic variables.

Analysis of surface and underground detector data from Mawson and Hobart for the period 1982 to 1988 has revealed a number of episodes of enhanced diurnal variation lasting more than 5 days. A preliminary study of these enhancements shows that variations in the rigidity spectrum and in the upper limiting rigidity must be present to explain the phenomenon.

Radio astronomy software has not quite kept up with recent developments for the display of, and interaction with, data. At the Australia Telescope National Facility we are trying to catch up by investigating how useful visualisation techniques and approaches like visual computing are for the reduction of radio data. I will discuss a few techniques that we have applied to radio data and comment briefly on their merits.

The effects of including low quality IRAS flux data in colour-colour diagrams is investigated, with a view to identifying Young Stellar Objects from the IRAS database. Colour criteria to perform this task are derived.

Ground-based observations of Type III bursts made with spectrographs and spectro-polarimeters, at frequencies above the ionospheric cut-off, reveal that most bursts (excluding storm Type IIIs) have fundamental (F) and harmonic (H) structure (Wild et al. 1959; Dulk and Suzuki 1980). An example of F-H bursts is given by Sheridan (1978). Such bursts are produced by streams of electrons travelling along open magnetic field lines and exciting plasma oscillations which are converted to electro-magnetic waves at both the F and H frequencies of the local plasma frequency in the corona.

In May 1984 site testing began for the Automated Patrol Telescope. A series of atmospheric extinction and night sky brightness measurements were made over the following year at Parkes and Siding Spring Mountain using B and V filters. Parkes revealed an extinction greater than that of Siding Spring and more prone to variation. Results for the night sky brightness indicated Parkes has a sky slightly brighter than that at Siding Spring. The paper discusses the procedures used for obtaining the results and their limitations.

Two important problems have emerged from observations of 18 cm OH emission sources that remain substantially unanswered by existing theories. The first is the problem of the origin of the high degree of circular polarization that is frequently observed. The second is what I have called the ‘problem of variety’: is it necessary to invoke a number of different physical mechanisms to explain the variety of qualitatively different behaviours observed, or can these different behaviours be explained by variations of one basic physical process?

Important observations of X-ray sources and searches for the optical counterparts of X-ray and radio pulsars require a capability of detecting and analysing light variations with a time scale of milliseconds. X-ray sources in binary star systems are expected to be collapsed objects – neutron stars or black holes (Peterson 1973) – and are expected to produce light variations. In the case of a neutron star, pulses with the same period as the rotation period of the neutron star would be produced, and such have been observed from Cen X-3 (schreier et al. 1972) in the X-ray, and from Her X-1 (Middleditch and Nelson 1973) and the Crab Nebula pulsar (Cocke et al. 1969) in the X-ray optical.

Spectropolarimetric observations of the 10 arc second region surrounding Eta Carinae have been made in the 8-13 μm wavelength band. The observed polarization, of a few percent, is due to emission of radiation from aligned grains. The radial position angle of the polarization suggests that gas streaming is responsible for the grain alignment.

More than 1000 coefficients of atmospheric extinction in the U, B and V passbands were obtained as a secondary result of long-term photometric monitoring of stellar objects at Yonsei University Observatory during 1982–1989. The long-term variation of the extinction coefficients of each passband are presented in this paper.

The detection of formaldehyde absorption of the microwave background radiation in a region of the Southern Coalsack (Sinclair and Brooks 1972) was made at about the same time as an optical study of this region (Tapia 1972) in which six globule-like clouds of interstellar dust were found. The size (0.3 pc) and position of the formaldehyde cloud were similar to the corresponding parameters of one of the globules (No. 2 on Tapia’s list).

The dynamics exhibited by systems, such as galaxies, are dominated by the isolating integrals of the motion. The most common are the energy and angular momentum integrals. The motions in a system with a full complement of isolating integrals are regular, that is, periodic or quasi-periodic. Such a system is integrable. If there is a deficiency in the number of integrals, then the motions are chaotic. There is a fundamental quantative difference in the motion, depending on the number of integrals. A technique, called Generalised Painlevé analysis, based on complex variable theory allows the user to determine if a system is integrable. Two new integrable cases of the Henon-Heiles system are presented, bringing the total number of such integrable potentials to five. It is highly probable that there are no further integrable cases of the Henon-Heiles potential. Five cases of the quartic Verhulst potential, defined by certain restrictions on the coefficients, which are found to be integrable are summarised.

Four tree ring-index site chronologies, representing standardised annual growth rates for spruce trees growing at high altitude sites in Colorado, have been employed as proxy data in a regression model for the annual variation of solar radio flux at 2800 MHz (F 10·7) and the Catania sunspot area (A c). These dendrochronological time series all exhibit significant power spectrum peaks at about 11 years and separately correlate with the annual values of R z, F 10·7 and A c, as solar activity indicators. The two models constructed give the cyclic variation of F 10·7 and A c back to AD1673.

Observational astronomy extends, in terms of energy in the electromagnetic spectrum, from below 10-8eV to above 108eV. Studies of cosmic rays extend this range to the neighbourhood of 1019eV (about a Joule) and the aspects of high energy astrophysics discussed in the present paper are those concerned with cosmic rays of energy upwards of about 1015eV.

The Llanherne telescope is a meridian transit instrument with an instantaneous bandwidth of two octaves in the range 35 to 150 MHz, and was constructed primarily for studying the low frequency properties of pulsars. The antenna is a 78 × 156 metre filled aperture phased array comprising 4096 wire dipole elements arranged in a 64 × 64 matrix. Uniform illumination of the elements produces a single pencil beam response which is scanned electronically along the meridian from Declination -90° to +30°. The beamwidth at 100 MHz is 1 degree in right ascension and two degrees sec(Dec.) in declination and varies proportionally with wavelength, giving a transit time of 4 sec(Dec) × 100/f(MHz) minutes between half power points.