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RSAA News of the Month: June 2004

Siding Spring Anniversary
Celebrating 40 years of Australia's Finest Optical Observatory

 

Forty years ago the first telescope began operation at the Australian National University's Siding Spring Observatory, near Coonabarabran, NSW. Today this telescope, the 40" reflector, is RSAA's main imaging telescope. During the 1960's two other telescopes joined the 40", a 16" designed for photometry and a 24" designed for polarimetry. Photometry measures the brightness and colour of stars and polarimetry measures the magnetic fields in space.

Left: The first telescopes on Siding Spring
Left to right, the 16", 24" and 40".

Right: The ANU telescopes today
The rectangular building on the left houses the UNSW Automated Patrol telescope.
Next to it is the dome of the Uppsala/RSAA Schmidt.
Right of centre is the dome of the 24", next to it the rectangular "dome" of the 2.3-m.
The 16" dome is just visible behind the 2.3-m and the dome of the 40" is on the far right.

Thirty years ago the largest telescope in Australia, the 4-m Anglo-Australian Telescope (AAT) was commissioned. The AAT has been one of the most productive telescopes in the world. It was shortly joined by the 1.2-m UK Schmidt Telescope (UKST), one of the most powerful survey telescopes of the era. The AAT and UKST form the Anglo-Australian Observatory (AAO).

Twenty years ago, the ANU 2.3-m Advanced Technology Telescope (ATT) was added to what was now one of the world's great observatories. The 2.3-m was the first optical telescope in the world to incorporate a thin mirror, an alt-azimuth mount, fully-integrated computer control and a coaxially-rotating building in the one design. It became the prototype of the "new-wave" of telescope designs. The 2.3-m is currently being upgraded with remote operating capability.

"Birthday Beauties", the magnificent AAT (30 yo) and ATT (20 yo)

Also at Siding Spring are the 0.5-m Uppsala/RSAA Schmidt telescope, the University of NSW Automated Patrol Telescope (APT), and the American Robotic Optical Transit Search Experiment (ROTSE). Two new telescopes will soon join the observatory. The 2-m Faulkes South Telescope will see first light later this year, and construction of the ANU 1.3-m ultra-wide field Skymapper will commence shortly.

To celebrate this 40/30/20th anniversary, RSAA hosted an Open Night on May 28, an Open Day on May 29, and an Anniversary Dinner on the evening of May 29.

Just before sunset on Open Night, two busloads of visitors gathered at the summit of Siding Spring. After being greeted by RSAA director Penny Sackett, they were split into groups and visited the 40", 2.3m, UNSW Automated Patrol Telescope, the AAT and the Faulkes South telescopes. Astronomers at each telescope explained their programs and showed the telescopes in operation and recently-collected data. Members of the Astronomical Society of Coonabarabran showed visitors the Moon, Jupiter and star clusters through smaller telescopes. Several hundred visitors from Coonabarabran and the surrounding region attended Open Day and were shown every instrument at the observatory.

Dusk on May 28
Visitors assemble on the summit, are split into guided groups, and move off to inspect telescopes in action.

Among the visitors to Open Day were the Mayor of Coonabarabran, Peter Shinton, and wife Julie.
They were shown the site by Director Penny Sackett,
discussed the AAT with Prof Ben Gascoigne and Dr Fred Watson,
and were impressed by the new Faulkes Telescope.

The Anniversary Dinner was held at the Coonabarabran Club. Eighty-five staff and ex-staff of Mt Stromlo and Siding Spring Observatories and the AAO, plus representatives from the University of NSW and the Faulkes Telescope Project attended. Highlight was the superb cake from Michel's Patisserie, decorated with an edible image mosaic of SSO telescopes.

Scenes from the dinner
A happy crowd, entertaining speakers, a well-stocked buffet, a superb 0.6 x 0.4-m cake,
a Director to slice it, and a great time was had by all.

Many tales of the early days were provided by speakers including Prof. Ben Gascoigne, the first astronomer to set foot on Siding Spring; engineer Hermann Wehner, who was involved in the construction of most of the telescopes; Chris McCowage, who has been with the AAO since its beginning; Penny Sackett, who leads us into the start of the next 40 years; and Vince Ford, collector of tales best left untold.

Siding Spring, in its 40th year, is truly one of the world's great observatories.

 

Supermassive Black Hole
Explodes a "Galaxy in a Box"

RSAA theoretical astronomers Ralph Sutherland and Geoff Bicknell have built a working computer model of a galaxy which contains a supermassive black hole. The hole ejects jets of plasma at near the speed of light in two giant ‘jets’. The jets are so powerful that they effectively explode the host galaxy.

The simulations, carried out on the ANU/APAC supercomputing facility, predict the appearance of what is known as a giant radio galaxy. The new methods being used allow the astrophysicists to predict how the radio galaxy will evolve over tens of millions of years.

The models have been compared to the nearest Quasar and powerful radio Galaxy, Cygnus A. Thanks to the efforts of Drs Sutherland and Bicknell, astronomers are now able to model and predict the apprearance of these objects simultaneously in the radio and the x-ray regime for the first time.

An X-ray image of the Cygnus A radio galaxy
showing the expanding ‘fireball’ of superheated plasma.
The image is from NASA's Chandra X-ray Observatory.

ANU supercomputer simulation of a similar galaxy
showing the thermal emission from the hot gas.

A radio image of Cygnus A from the Very Large Array (VLA)

Synthetic radio image from the ANU simulation

An animation (requires Quicktime) of the simulated explosion and development of the jets can be viewed here.

The simulations are carried out in a virtual cube (the box) that represents a volume of space around the model galaxy. The cube is divided into 16.8 million sub-cells, and the computer calculates the flow of plasma in and out of each box as the explosion evolves. These new models will be used to study the evolution of radio galaxies, and the effect that the central black hole has on the way stars form in their host galaxies.

For previous Monthly News items, click here.