The primary function of the 64-m telescope, situated at Tidbinbilla near Canberra, is to communicate with and to control NASA’s unmanned interplanetary space craft (Reid et al. 1973). Similar telescopes are situated at Goldstone in California and in Madrid and are part of the NASA-JPL Deep Space Network (DSN). Under the Host Country Radio Science Agreement between the U.S. and Australia the telescope is available to Australian astronomers at times outside those committed to normal tracking. A radiometer operating at λ = 13.5 mm has been built by CSIRO for use on the 64-m telescope. It was initially used for VLBI observations of water vapour masers on baselines between the U.S., Australia and USSR (Batchelor et al. 1976).

In conjunction with the Australian Government's Spectrum Management Agency, experimental tests have been carried out to determine the susceptibility of the Molonglo Observatory Synthesis Telescope (MOST) to interference from terrestrial transmitters. The motivation for the tests was to reconcile the conflicting requirements of the MOST, which is committed to an extensive survey of the southern sky at 843 MHz, with the commercial use of the 825–845 MHz band, which is being prepared for sale. The tests show that the far sidelobe gain of the MOST, relative to an isotropic antenna is generally less than 1, and that an appropriate interference criterion would be that in-band interference irradiance should not exceed −173 dBWm−2. This value is similar to that considered by the International Telecommunications Union to be detrimental to radio astronomy continuum observations at nearby frequencies.

Historically, infrared instrumentation for astronomical research has been developed by individual groups largely for their own enjoyment. The commissioning of the AAO’s infrared photometer-spectrometer (IRPS) in late 1978 provided for the first time in Australia a common-user instrument. Since then it has attracted considerable interest and is now the second most popular instrument in use at the AAT.

Dissipation of shock waves has often been proposed as the energy source required to sustain the outward temperature rise in the solar atmosphere. Theoretical models for the heating process have been developed by equating the mechanical energy input to the radiative energy loss at each height, but neither of these processes is well understood, and the lack of data means that the models are necessarily crude.

A comprehensive study of the anisotropy (i.e. streaming) of solar cosmic rays at energies ~10 MeV revealed two distinct types (McCracken). The first occurs during onset phase of the event, is large (> 20%), and is really the flow of cosmic rays along lines of force driven by a density gradient. The second describes the decay of the event, is small (10%), and indicates a flow radially away from the Sun.

Until the last six years few infrared observations of astronomical objects (other than the Sun and planets) had been attempted. Those few were primarily concerned with obtaining bolometric corrections and effective temperatures, the variation of bolometric magnitudes of late-type variables, and the derivation of the laws of interstellar extinction.

When the separation between two stars becomes sufficiently small, tidal forces may cause one or both stars to disrupt. Roche (1850) studied the problem of the stability of a liquid in synchronous, circular orbit with a point mass, and predicted an instability of the liquid star for separations ≤ 2.5 r S⅓ where R is the initial radius of the liquid star, and S is the ratio of the mass of the point to the mass of the liquid star. Darwin generalized the problem to allow for two liquid stars in circular orbit. The whole of the classical research has been systematically analysed by Chandrasekhar (1969) using the tensor virial method. An error in Chandrasekhar’s analysis was corrected by Tassoul (1975).

The 16-inch telescope on Canopus Hill (Tasmania) has been equipped with a Coudé spectrograph.

Semiconvection is the name given to a situation that arises in the evolution of large-mass main-sequence stars and lower-mass horizontal-branch stars, in which a layer forms where almost all of the heat flux is transported by radiation, but where slow convection is required to redistribute a stably stratified solute (e.g. helium). For a general discussion on semiconvection, see Spiegel (1969). The main problem is to determine the correct relationship between the solute distribution and the temperature gradient in the inhomogeneous layer. Ledoux (1947) and Schwarzschild and Harm (1958) have proposed two very different prescriptions. Since theory and experiment indicate that the Schwarzschild-Harm (SH) prescription is correct for the onset of convection (in the form of overstability), Spiegel (1969) has proposed that SH are correct. However, neither observation (oceanographic or laboratory) nor theory precludes a substantial deviation from the SH prescription as applied to finite amplitude semiconvection. The observational evidence is only readily applicable to stars if Pr≳, 1, where Pr is the Prandtl number of the fluid. In fact, Pr≪ 1 in stars. It is shown below that if one could have stars in which Pr ≳ 1, then the SH prescription would probably be wrong, and the Ledoux criterion might then be nearer to being correct. In the real situation (Pr≪ 1), observations or experiments are lacking and theory alone does not provide an unequivocal answer to the problem. This paper does not attempt a complete discussion of the problem, and a more detailed report will be submitted elsewhere. Some aspects of the problem have already been discussed in the context of the giant planets (Stevenson and Salpeter 1977).

One of the important discoveries of astronomy is that the Universe expands: distant galaxies have large recession velocities in direct proportion to their distances. Attempts to determine a global value for the constant of proportionality between the velocity and the distance (Hubble constant) are met with difficulties by the presence of peculiar, random and streaming motions in the local region. These peculiar motions are either of primordial origin or the effect of density perturbations. These affect the mean velocity of the nearby groups in the level of 50-100 km/sec (Tammann, Sandage and Yahil 1980). However, the expected peculiar gravitationally induced motion of the Local Group towards the Virgo cluster, could be large due to the high density contrast in that direction (Sciama 1967; de Vaucouleurs and Peters 1968; Sandage, Tammann and Hardy 1972; Jones 1976). This infall motion could be as high as 500 km/sec if the anisotropy of the microwave background is interpreted to have a component of our peculiar motion towards the Virgo cluster (Peebles 1971, Boughn, Cheng and Wilkinson 1981; Gorenstein and Smoot 1981).

We construct an idealised universe for didactic purposes. This universe is assumed to consist of absolute Euclidean space and to be filled with a classical medium which allows for sound waves. A known solution to the wave equation describing the dynamics of the medium is a standing spherical wave. Although this is a problem of classical mechanics, we demonstrate that the Lorentz transformation is required to generate a moving solution from the stationary one. Both solutions are here collectively referred to as “spherons”. These spherons exhibit properties which have analogues in the physical description of matter with rest mass, among them de Broglie like phase waves and at the same time “relativistic” effects such as contraction and a speed limit. This leads to a theory of special relativity by assuming the point of view of an observer made of such spheronic “matter”. The argument made here may thus be useful as a visualisation or didactic approach to the real universe, in which matter has wave-like properties and obeys the laws of special relativity.

We present VLA 21-cm observations of the spiral galaxy ESO 481-G017 to determine the nature of remote star formation traced by an Hii region found 43 kpc and ∼800 km s−1 from the galaxy center (in projection). ESO 481-G017 is found to have a 120 kpc Hi disk with a mass of 1.2 × 1010M⊙ and UV GALEX images reveal spiral arms extending into the gaseous disk. Two dwarf galaxies with Hi masses close to 108M⊙ are detected at distances of ∼200 kpc from ESO 481-G017 and a Hi cloud with a mass of 6 × 107M⊙ is found near the position and velocity of the remote Hii region. The Hii region is somewhat offset from the Hi cloud spatially and there is no link to ESO 481-G017 or the dwarf galaxies. We consider several scenarios for the origin of the cloud and Hii region and find the most likely is a dwarf galaxy that is undergoing ram pressure stripping. The Hi mass of the cloud and Hi luminosity of the Hii region (1038.1 erg s−1) are consistent with dwarf galaxy properties, and the stripping can trigger the star formation as well as push the gas away from the stars.

The Sloan Digital Sky Survey has been immensely successful in detecting new Milky Way satellite galaxies over the past seven years. It was instrumental in finding examples of the least luminous galaxies we know in the Universe, uncovering apparent inconsistencies between cold dark matter theory and dwarf galaxy properties, providing first evidence for a possible lower mass limit for dark matter halos in visible galaxies, and reopening the discussion about the building block scenario for the Milky Way halo. Nonetheless, these results are still drawn only from a relatively small number of galaxies distributed over an area covering about 29% of the sky, which leaves us currently with more questions than answers. The study of these extreme stellar systems is a multi-parameter problem: ages, metallicities, star formation histories, dark matter contents, population fractions and spatial distributions must be determined. Progress in the field is discussed and attention drawn to some of the limitations that currently hamper our ability to fully understand the phenomenon of the ‘ultra-faint dwarf galaxy’. In this context, the Stromlo Milky Way Satellite Survey represents a new initiative to systematically search and scrutinize optically elusive Milky Way satellite galaxies in the Southern hemisphere. In doing so, the program aims at investigating some of the challenging questions in stellar evolution, galaxy formation and near-field cosmology.

In recent years, formal astronomy education has become an issue of great interest. Indeed, some boards of education now officially include astronomy in their curricula. While formal astronomy education continues to gain attention, informal astronomy education for the general public has rarely been addressed. One valuable source of informal astronomy education is the observatory ‘visitor centre’. Observatories draw thousands of visitors each year, and as such represent a golden opportunity for the astronomical community to communicate directly with the public. This paper summarises an exploratory study of the cognitive and affective impacts of a visit to the visitor centres located at Mount Stromlo and Siding Spring Observatories.

The unprecedented imaging power of James Webb Space Telescope (JWST) provides new abilities to observe the shapes of objects in the early Universe in a way that has not been possible before. Recently, JWST acquired a deep field image inside the same field imaged in the past as the Hubble Space Telescope (HST) Ultra Deep Field. Computer-based quantitative analysis of spiral galaxies in that field shows that among 34 galaxies for which their rotation of direction can be determined by the shapes of the arms, 24 rotate clockwise, and just 10 rotate counterclockwise. The one-tailed binomial distribution probability to have asymmetry equal or stronger than the observed asymmetry by chance is $\sim$0.012. While the analysis is limited by the small size of the data, the observed asymmetry is aligned with all relevant previous large-scale analyses from all premier digital sky surveys, all show a higher number of galaxies rotating clockwise in that part of the sky, and the magnitude of the asymmetry increases as the redshift gets higher. This paper also provides data and analysis to reproduce previous experiments suggesting that the distribution of galaxy rotation in the Universe is random, to show that the exact same data used in these studies in fact show non-random distribution, and in excellent agreement with the results shown here. These findings reinforce consideration of the possibility that the directions of rotation of spiral galaxies as observed from Earth are not necessarily randomly distributed. The explanation can be related to the large-scale structure of the Universe, but can also be related to a possible anomaly in the physics of galaxy rotation.

In this work, we present a methodology and a corresponding code-base for constructing mock integral field spectrograph (IFS) observations of simulated galaxies in a consistent and reproducible way. Such methods are necessary to improve the collaboration and comparison of observation and theory results, and accelerate our understanding of how the kinematics of galaxies evolve over time. This code, SimSpin, is an open-source package written in R, but also with an API interface such that the code can be interacted with in any coding language. Documentation and individual examples can be found at the open-source website connected to the online repository. SimSpin is already being utilised by international IFS collaborations, including SAMI and MAGPI, for generating comparable data sets from a diverse suite of cosmological hydrodynamical simulations.

The time scales in the s process appears to be an approriate aspect to discuss at the occasion of Roberto's 70th anniversary, the more as this subject has been repeatedly addressed during the 20 years of collaboration between Torino and Karlsruhe. The two chronometers presented in this text were selected to illustrate the intense mutual stimulation of both groups. Based on a reliable set of accurate stellar (n, γ) cross sections determined mostly at FZK, the Torino group succeeded to develop a comprehensive picture of the various s-process scenarios, which are most valuable for understanding the composition of the solar system as well as for the interpretation of an increasing number of astronomical observations.

The performance of the mysql and oracle database systems have been compared for a selection of astronomy queries using large catalogues of up to a billion objects. The queries tested are those expected from the astronomy community: general database queries, cone searches, neighbour finding and cross matching. The catalogue preparation, sql query formulation and database performance is presented. Most of the general queries perform adequately when appropriate indexes are present in the database. Each system performs well for cone search queries when the Hierarchical Triangular Mesh spatial index is used. Neighbour finding and cross matching are not well supported in a database environment when compared to software specifically developed to solve these problems.

In 1994, the New South Wales Board of Studies, Australia, introduced three high level Distinction Courses for gifted and talented students: Comparative Literature, Cosmology, and Philosophy. All are offered by distance education but the cosmology course employs an interactive design model and an extensive communication system that differentiates it from the other two. This paper explains the model and the way it is used in practice to organise, sequence and deliver the course. A discussion addresses ways in which the model might be used to design a wider range of courses in science for gifted and talented students.

We study the contents of an apparent void in the distribution of Lyα emitting galaxies at redshift 2.38. We show that this void is not empty, but contains a damped Lyα absorption-line system, seen in absorption against background QSO 2138-4427. Imaging does not reveal any galaxy associated with this absorption-line system, but it contains metals (Fe/H ∼ −1.3), and its large velocity range (∼180 km s−1) implies a significant mass.