With a number of important exceptions associated with transitory flare activity, most persistent sources of solar radio emission observed to date with the 80 MHz Culgoora radioheliograph have been stable in position over periods of tens of minutes or hours even though they fluctuated greatly in intensity. During several hours on 1968 November 11, however, we observed some interesting activity which showed frequent changes in the position of a source.

The classical model of the interstellar medium consists of cool clouds (typical temperature 80 K, number density 20-40 cm-3) moving through a warmer interstellar medium (104 K, 0.15-0.3 cm-3) at a rms velocity of ~ 10 km s-1. More recent models have included the coronal gas (106 K) as part of this medium. We consider the collisions of these clouds in order to determine whether these collisions initiate star formation and/or change the state of the interstellar medium.

A theory of linear acceleration emission, with possible application to pulsars, is developed. The equation of motion for a relativistic charged particle accelerated in the field of a longitudinal wave is solved to first order in the electric potential and used to derive the first order current. The power emitted and the absorption coefficient are calculated and the conditions under which masing can occur are discussed.

A survey has been made of 139 bright southern galaxies using the 1´.5 X 4° fan beam of the E-W arm of the Mills cross. These represent a largely complete sample of galaxies down to a limiting total optical magnitude of ~11.0 when corrected for Galactic absorption by 0.35 cosec β and for internal absorption due to the tilt of the emitting galaxy. Of these, 54 were detected down to a limiting radio flux of 0.4 f.u., at which level the probability of a misidentification is 10%. No a priori distinctions were made between the galaxies on the basis of strong radio emission or optical peculiarities.

In the astrophysical context, where the effects of a magnetic field on stellar convective processes have to be taken into account, we have ϰ > > η > > ν (Weiss 1977) where ϰ, η and ν are respectively the thermal, magnetic and viscous diffusivities.

On 1971 January 24 a 3B flare at 18° N., 49° W. was associated with the acceleration of protons to relativistic energies; it was one of the rare events recorded by ground-level neutron monitors. Excellent radio coverage was obtained with single-frequency radiometers in the range 1000-9400 MHz, and at Culgoora with the 8-8000 MHz spectrograph and the 80 MHz radioheliograph. At the Earth relativistic protons and electrons arrived very promptly from the flare, whose site was near the foot of the nominal interplanetary field line which connects to the Earth.

During 1971/72 the radioheliograph at Culgoora, N.S.W. was used to observe 30 bright galaxies at 80 MHz.

The Modern Laplacian Theory (Prentice 1978) of the origin of the solar system assumes a non-dissipative model of supersonic turbulence and the existence of stable rings left behind during the contraction of the proto-Sun. We show by numerical simulation that the turbulence is highly dissipative and the rings are unstable. As a result of the instability the rings spread and interact with the proto-Sun. The rings therefore cannot form in the way Prentice has proposed.

Type I storms generally occur in association with large sun-spots and the radiation is usually circularly polarized. Statistically it has been found that the sense of polarization, right-hand (RH) or left-hand (LH), usually corresponds to the ordinary magneto-ionic mode in the field of the dominant spot of the active region; when a following spot dominates, the polarization tends to be determined by this spot rather than by the leading field. One-dimensional position measurements show that the type I sources are usually not radially above the active region but are displaced by a few minutes of arc. The source sizes are about l′.2 to 4′.5 at 169 MHz and the sources frequently contain double, multiple or bipolar structure at 80 and 160 MHz.

DI Peg has been recognised as an eclipsing system since 1934 when Morgenroth (1934) discovered its variability. For over fifty years, many observers [Jensch (1934), Opalski (1936), Tsesevich (1954), Szafraniec (1956), Kruszewski (1956), Huth (1966), Rucinski (1967), Binnendijk (1973)], have studied this system. DI Peg was observed at Midway Observatory (M.O.) during 1976 and 1977 (Kennedy 1978). Considering the erratic period changes of the system, it appeared desirable to check the system again during 1980.

The earlier work on the production of deuterium in the accretion tori around Population III objects has been criticised on the basis of relative production ratios of deuterium, helium-3 and 7Li. It is shown here that the criticism on the basis of helium-3 over-production is unjustified, as no measurement of helium-3 and lithium abundances for the same stars is available. It is predicted that indeed the helium-3 abundance determination will be the best means to verify the original hypothesis.

A new distance modulus (31.23) to the Virgo cluster is derived using the distances to nearby galaxies given by Sandage and Tammann, de Vaucouleurs, ourselves and DDO observers. This when combined with the undisturbed mean Virgo cluster velocity 1182 km s-1, gives a value for the global Hubble constant as 67 ±4 km s-1Mpc-1.

At present there are two general theories of the origin of cosmic rays. One is that most, if not all, galactic cosmic rays originate within the Galaxy, probably during supernova explosions. The other is that cosmic rays pervade the universe, originating mainly in the powerful radio galaxies and possibly in quasars, where vast stores of energy are available. The former theory has been discussed in detail by Ginzburg and Syrovatskii, while proponents of the latter theory include Burbidge and Hoyle, and Burbidge.

The Windsor amateur astronomer, John Tebbutt, had a ceased observing in 1907. However, in 1909, at the age of 75, he came out of retirement to observe Halley’s comet and his astrometric positions were published in the Monthly Notices of the Royal Astronomical Society. These data were used, together with most published observations from the 1835 and 1910 apparitions, for the computation of Halley’s orbit for ESA’s Halley intercept spacecraft, Giotto. A detailed analysis of the observations have shown minor imperfections that, when corrected, gave rms errors of 3''.5 arc in right ascension and 2''.8 in declination. His systematic errors are negligible at the 0''.2 level.

We summarise recent developments in modelling SN 1987A including the progenitor’s evolution, explosive nucleosynthesis, optical, X- and γ-ray light curves, and dust formation. The distribution of heavy elements in the ejecta is inferred from the light curves. The pre-peak optical light curve as well as early emergence of X- and γ-ray indicate the mixing of 56Ni into the hydrogen-rich envelope. The plateau-like peak of the optical light curve is well reproduced if hydrogen is mixed into the deep core. The flat X-ray light curve observed by Ginga would be due to the clumpy structure of the core. The progenitor’s blue-red-blue evolution and nitrogen abundance suggest that the progenitor’s hydrogen-rich envelope had mass M env = 7 − 11 M⊙ and was almost completely mixed.

A general method is described for estimating the position, integrated flux density and the second moments of the flux density distribution for sources in a two dimensional map. The method requires accurate knowledge of the beam shape of the telescope. Uncertainty estimates and significance levels of the source parameters are easily obtained.