A satellite receiver that works like a giant eyeball has arrived in Sydney
for testing by CSIRO.
Its arrival brings a step closer one idea for the world’s next
‘mega-telescope’ — an army of giant spheres to collect radio waves from
the cosmos, dotted in patches across the landscape.
Testing the ‘eyeball’ will help CSIRO refine the mathematics and software
for designing its own spherical collectors for the mega-telescope.
The 1-m white sphere has the same function as a satellite dish —
collecting and concentrating radio waves. It’s a lens that focuses radio
waves to a point, just as the lens in your eyeball focuses light to a
point on your retina.
And like your eye, but unlike today’s radio telescopes or communications
antennas, the lens can ‘see’ many radio sources in the sky at once.
This ‘Luneburg lens’ is a commercial one built in Russia: they are not
readily available in western countries. But CSIRO engineers realised they
offered unique advantages for the technically challenging mega-telescope.
Australia is one of the most active of the 11 countries now planning this
telescope, called the Square Kilometre Array or SKA. Construction will
start around 2010.
The telescope’s prime goal is to look far back enough into the early
Universe to see the first galaxies forming.
It will be a hundred times bigger than even today’s biggest telescopes,
all the better to capture the weak whispers from the early Universe.
Its total collecting area — one square kilometre or one million square
metres — will not be a single huge surface. Instead it will be many small
surfaces, grouped in patches.
Several concepts for the telescope have been put forward. They range from
large collectors set into the ground to a swarm of satellite dishes.
Australia’s visions are the most radical and include Luneburg lenses or a
‘phased array’ of small flat collectors.
“The SKA would need tens of thousands of Luneburg lenses, each about five
metres in diameter,” says Dr Peter Hall, CSIRO SKA Program Leader.
“We need to find cheap and easy ways to mass-produce them.”
The Russian lens is made of high-density polystyrene. CSIRO is developing
lighter, cheaper materials that absorb less of the precious radio signal.
“These materials can be applied in many other areas of radio and antenna
engineering,” said Dr Andrew Parfitt of CSIRO Telecommunications and
Industrial Physics.
CSIRO is a member of the Australian SKA consortium, which is coordinating
Australia’s participation in the project.
“We aim to build a ‘demonstrator system’ of lenses or flat collectors to
show that the ideas will work,” says Dr Hall. “They’d be built alongside
CSIRO’s existing Australia Telescope at Narrabri and integrated with it.”
This would both test the viability of the technology and make the
Australia Telescope uniquely able to see many different parts of the sky
at once.
“If we get the funding to do this we’ll be letting contracts to Australian
industries to build the collecting elements,” Dr Hall says.
Australia will unveil these plans at a major international meeting on the
SKA that starts on 9 July at the University of California Berkeley.
As well as undertaking technical work, Australia has also begun to test
possible SKA sites — the first country to do so.
“The site has to meet various technical requirements. One of the most
important is being in an area relatively free of man-made radio signals,
which can swamp the extremely weak cosmic signals,” Dr Hall explains.
“In this respect, Australia has the edge over many other countries,” he
says.
Some initial site testing has been done in Western Australia. Other areas
of Australia will be looked at too.
“The SKA site will be chosen by the international astronomy community in
2005,” Dr Hall says. “They know that Australia would be a good host
country — it has an interference-free environment, is politically stable,
it’s technologically sophisticated and the climate is suitable.”
“But we still need to do a lot of groundwork before we put in a bid to
host.”
An economic analysis has shown that the benefits of hosting the
billion-dollar telescope would amply repay Australia’s investment in it,
he said.
The countries currently participating in the international SKA consortium
are Australia, Canada, China, Germany, India, Italy, Poland, The
Netherlands, Sweden, the U.K. and the U.S.A.
More information:
Dr Peter Hall
CSIRO Australia Telescope National Facility
02-9372-4195, 0400-801-531
Peter.Hall@atnf.csiro.au
Dr Andrew Parfitt
CSIRO Telecommunications and Industrial Physics
02-9372-4187, 0408-164-432
Andrew.Parfitt@tip.csiro.au
Ms Helen Sim
CSIRO Australia Telescope National Facility
02-9372-4251, 0419-635-905
Helen.Sim@atnf.csiro.au
Vision (Betacam SP):
* Animated ‘flyover’ of an array of Luneburg lenses in the Australian
landscape
* B-roll of CSIRO’s Australia Telescope Compact Array
Contact Helen Sim, CSIRO Australia Telescope National Facility
02-9372-4251, 0419-635-905, Helen.Sim@atnf.csiro.au
Further information and pictures:
Low resolution jpeg image:
http://www.atnf.csiro.au/SKA/SKA_circ_a4.jpg
10 Mb jpeg image:
http://www.atnf.csiro.au/SKA/SKA_circ_a4_hires.jpg
Simple animated gif showing how a Luneburg lens focuses:
http://www.atnf.csiro.au/SKA/ll_animation.html
Russian lens being tested by CSIRO:
http://www.atnf.csiro.au/SKA/konkur_lens.html
MPEG movie — animated ‘flyover’ of an array of Luneburg lenses in the
Australian landscape:
http://www.atnf.csiro.au/SKA/movie.mpg
IMAGE CAPTION:
[http://www.csiro.au/page.asp?type=imageDef&id=luneburglge (162KB)]
CSIRO’s Dr Peter Hall with the Russian Luneburg lens, being tested at
CSIRO’s Radiophysics Laboratory in Sydney. Photo: David Smyth.
Contacts:
Ms Helen Sim
Sector Communicator
Australia Telescope National Facility
PO Box 76
Marsfield NSW 1710
Phone: +61 2 9372 4251
Fax: +61 2 9372 4310
Email: hsim@atnf.csiro.au
Ms Rosie Schmedding
Communicator
CSIRO National Awareness
PO Box 225
Dickson ACT 2602
Phone:+61 2 6276 6520
Fax:+61 2 6276 6821
Mobile: +61 0418 622 653
Email:Rosie.Schmedding@nap.csiro.au
