Talk

Background Radiation in Two Spectrums

Chris Morley

LVAS

The existence of the Cosmic Microwave Background was predicted some years before it was discovered in 1965. Since then, it has been mapped in great detail by a succession of dedicated probes. I will discuss how and why it exists as well as what it means for our understanding of the universe. Whilst detection of gravitational waves from relatively close inspiral events has been occurring since 2015, it was just last year that the presence of ultra-low frequency gravitational waves was confirmed. I will explain how the Murriyang Parkes radio telescope played an important role in finding evidence of background gravity waves, which are thought to have originated from the mergers of super massive galaxies.

Serpentinization - the source of energy, catalysts and nutrients for life to emerge on Earth in the Hadean aeon

David J. W. Moriarty

AAQ, VSS, UQ

The emergence of life on Earth 4 billion years ago depended on the reduction of carbon dioxide and nitrogen by hydrogen under alkaline conditions produced by serpentinisation. Serpentinisation occurs when rocks that have a high content of magnesium and iron in the ferrous redox state and low silicate content, react with water percolating through them, producing hydrogen, serpentine, magnetite and brucite. Hydrogen in serpentinising systems also reduces iron and nickel to their elemental state, forming awaruite, which catalyses the carbon dioxide reduction by hydrogen.

The products of reactions catalysed by awaruite and other transition metals include carbon monoxide, formate, methane, acetate and pyruvate; these are primary organic chemicals at the base of networks leading to synthesis of more complex compounds. Amino acids, which are also essential for autocatalytic networks leading to life, are formed from ammonia produced by the reduction of nitrogen (N2) by hydrogen in serpentinising systems. The cofactor in the enzyme nitrogenase, which dates from the last universal common ancestor of bacteria and archaea, contains molybdenum, iron and sulphur in its active centre.

The geological conditions setting the stage for serpentinisation and life to start on Earth suggest it may not have developed with serpentinisation on Mars or Enceladus if they did not have a large amount of carbon dioxide in their oceans when they formed.

Bubbles in the early Universe

Balu Sreedhar

The University of Melbourne

Happening less than a billion years after the Big Bang, the formation of the first luminous sources, such as the first stars and galaxies, characterises the Cosmic Dawn. This led to the Epoch of Reionisation (EoR), the last major phase change of the hydrogen atoms in the Universe when the intense UV radiation produced by the first stars ionised them and had a lasting impact on all subsequent galaxy formation and evolution. With the recent launch of JWST and upcoming facilities such as the Square Kilometer Array, astronomy is poised to make huge strides in the elucidation of the important astrophysical recipes of these exciting periods. In this talk, I will give a basic introduction to the (astro)physics of the EoR and my contribution to the making realistic simulations of this exciting period.

Determining the Eccentricity of the Earth's Orbit and the Tilt of the Earth's Axis

Stephen Broderick

St Ursula's College, Toowoomba

After working on Tycho Brahe's Mar's data for several years, Kepler was able to determine that the orbit of Mars was elliptical. Kepler correctly inferred that all planets travel in elliptical orbits. The eccentricity of the Earth's orbit took hundreds of years to be accurately determined. Today it can be calculated by using several images of the Sun from either the internet or by using a DLSR camera with a telescope. Ten weekly images of the Sun can be used to determine the perihelion and aphelion of the Sun, which in turn allows for the eccentricity of the Earth's orbit to be calculated.

A solargraph is made with a pinhole camera and displays the altitude of the Sun throughout the day on photographic paper. Solargraphs made over several days, weeks or a whole year reveal interesting information about the location’s length of daylight hours and maximum altitude of the Sun. From this information, you can accurately determine the tilt of the Earth’s axis and even the latitude of the location. Examples of solargraphs will be presented during the presentation.

Both of these activities have been used as assessment tasks in senior mathematics by the author.

AIP4Science - The successor to AIP4Win

Steve Rowlands, Richard Berry

AIP4Win, written by Richard Berry, has been a significant astronomical image processing program for many years, especially useful in reducing astronomical images for obtaining and reporting photometric data. With the increase in image size in MB and the memory limitations of the Visual Basic programming language used by AIP4Win, the time had come to completely rewrite AIP4Win.

This presentation will demonstrate the current progress of the rewrite and mention possible new features that are being considered.

A Backyard Radio Telescope

Robert Shaw

CSIRO

In this presentation, I will describe how I put together a VHF two-element phase-switched interferometer from Murchison Widefield Array (MWA) antennas and surplus lab equipment. The interferometer has the same architecture as that described in Martin Ryle's classic 1952 paper "A new radio interferometer and its application to the observation of weak radio stars". Improvements in electronics technology over the past seventy years now bring a project like this within the reach of the skilled amateur. Sample observations will be presented, showing interference fringes from the Sun and stronger radio sources.

Teaching Astronomy Authentically

Geoff McNamara

MSATT, Mount Stromlo Observatory

MSATT is a teaching facility for students in Years 8 to 12 at Mount Stromlo Observatory providing the opportunity to use sophisticated instruments to gather and analyse data firsthand. Students conduct investigations lasting up to two years. Tuition is provided by professional or advanced amateur astronomers in the making and analysis of observations, culminating in a formal, referenced, and refereed report. The main telescopes are a 30 cm SCT, and a 40 cm Newtonian on robotic mounts (Paramount ME and ME II). Instruments include CCD and CMOS cameras, and a range of spectrographs. While investigations in all branches of astronomy are possible, growth areas include spectroscopy, photometry, and lunar studies. A prototype radio telescope is currently being used to assess the potential for education in the radio spectrum. As far as the author can tell, MSATT is unique in its goals and methods. Others willing to copy the model are encouraged.

Amateur Radio Interferometry

Brett Dawson

Society of Amateur Radio Astronomers (SARA), and British Astronomical Association (BAA)

An overview of amateur radio interferometry at 4.9 GHz using analogue and digital techniques.

- interferometry and why it's a great choice for amateur radio astronomers,
- repurposing satellite receiver system hardware,
- analogue and digital backends,
- typical results from an amateur radio interferometer,
- further information and active amateur radio astronomy groups.

The Cranbourne Meteorite Fall

Dr Peter Skilton, John Cleverdon

MPAS (Mornington Peninsula Astronomical Society)

In the mid-1800's, the largest known iron meteorite in the world was encountered by chance by European settlers south east of Melbourne in the township of Cranbourne, where it had rested for about a century. This 3.5 tonne behemoth subsequently proved to be merely the first fragment of a larger parent meteoroid, as further finds have come to light since then, spread over tens of kilometres. More pieces are yet to be discovered in the surrounding regions that are fast being urbanised.

This talk summarises and characterises the 13 known discoveries so far, shows what can be deduced from them, and lays the groundwork for future discoveries to be made for this fall before suburbia erases them forever.

This work continues a long term project started in 1990 to understand the historical Cranbourne meteorite and the dynamics of its descent, with the aim of helping to find further meteoritic fragments for educational and scientific purposes.

Amateur Radio Astronomy at the ASV

Philip Costigan

Astronomical Society of Victoria

The Astronomical Society of Victoria has had a Radio Astronomy Section since the late 1980's. Back then we began a project to build a 4 metre steerable radio astronomy dish. Many years of trial and error working on the 4 metre dish eventually led to the project being abandoned.

Some years later the ASV was gifted a "dark sky" property just north of Heathcote in Victoria by Leon Mow. The Radio Astronomy Section was allotted an area in the property, where a shipping container was placed for a laboratory to house our equipment. We appropriately called this the LMRO or Leon Mow Radio Observatory. Many projects started to spring up at LMRO, and as confidence built, our members started toying with the idea of attempting to build another radio astronomy dish. In 2012, our then section leader, Clint Jeffery, acquired an 8.5 meter dish from an amateur radio enthusiast who had great intentions but just couldn't get around to it.

We now had a dish. Nothing else. Just a dish. So began the project of building an 8.5 meter all steerable radio astronomy dish for the ASV.

This talk will describe the steps involved in building this now operational telescope.