The flux densities of 220 radio sources have been accurately measured at 408 MHz in order to provide a useful set of calibration sources accessible to southern radio astronomers. The flux densities are based on a scale defined by absolute measurements. This scale appears to be 10% higher than the commonly accepted CKL scale and about 8% higher than the scale defined by Kellermann when averaged over common sources.

The three objects Tau X−1, Cyg X−l and GX3+1 are the most prominent discrete X-ray objects in the sky at photon energies of ≃ 100 keV.

This paper presents evidence for the existence of a previously unobserved X-ray source in the constellation Cetus. The astronomical significance of an intense X-ray object located so far from the galactic disk has prompted this preliminary report.

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.

The study of line-broadening mechanisms puts at our disposal an extremely useful tool for the investigation of physical conditions in plasmas, both stellar and laboratory.

Correlation radiotelescopes have become increasingly important in the last few years in all types of astronomical observations. These instruments operate by multiplying (correlating) the outputs of two separate aerials in order to provide a composite antenna with a range of aerial spacings and orientations. As a general rule this range of spacings is truncated at both the largest and smallest spacings, the largest spacing being determined by the area available or by the cost of the system, and the lowest spacing by either cross coupling between the multiplying elements (as in the Mills Cross type) or by the geometrical size of the elements (as in the compound interferometer type).

Worm-gear drives for astronomical telescopes have associated with them certain requirements which cannot be effectively dealt with by applying standard design methods and parameters, since these drives differ in many ways from conventional power transmission gearing.

The overall aim of the planned astronomical programme at Hobart (University of Tasmania) is to obtain stellar and planetary spectra in the ultra-violet, visible, and infrared regions of the spectrum. The major instruments to be used are a 16-inch telescope, a 40-inch telescope, and a solar spectrograph. Included in the project is a programme of laboratory studies, aimed at making quantitative comparisons of several of the most efficient methods for detecting and recording spectra from astronomical objects with low levels of flux. In addition, several new methods will be investigated. These will be referred to later in this paper.