CSIRO 'Camera' Now Boosting World's Largest Telescope
CSIRO-built equipment has been installed on the world's largest radio telescope to allow it to scan the sky seven times faster than it can now, and see further out into space.
The $1.4 million instrument is essentially a camera that uses radio waves instead of light to make pictures of galaxies and gas clouds in space.
Called ALFA (Arecibo L-band Feed Array), it is about the size of two washing machines stacked on top of each other, and weighs more than 600 kg.
The instrument was flown from Sydney to the Caribbean island of Puerto Rico then trucked 100 km to the Arecibo telescope, a 305-m diameter dish set into the ground.
On Wednesday 21 April it was slowly winched from the centre of the dish to a platform suspended 150 m overhead and then connected to the telescope's fibre-optic signal cables.
On hand to help install it were Mr Graeme Carrad, CSIRO's Project Manager for ALFA, and Mr Pat Sykes, who was responsible for the mechanical design and cryogenics.
“Australian astronomy technology is world-class,” says Professor Brian Boyle, Director of CSIRO's Australia Telescope National Facility, which built ALFA. “The world is beating a path to our door for it.”
“Traditionally, radio telescopes have been able to see only one spot on the sky – only one pixel – at a time,” explains Dr Warwick Wilson, Head of Engineering at the CSIRO Australia Telescope National Facility.
“To make a picture you had to image one spot after another.”
“But ALFA lets the telescope see seven times more sky – seven pixels – at once. This slashes the time needed to make surveys of the whole sky,” he says.
Arecibo Observatory staff are building other equipment to complement the ALFA receiver, such as ultra-fast data processors.
Dr Lister Staveley-Smith, Head of Astrophysics at CSIRO's Australia Telescope National Facility, says that ALFA will be used mainly for doing deep and powerful searches for other galaxies beyond ours, hunting for the small spinning stars called pulsars, and mapping out the hydrogen gas – the raw material for forming stars – in our own Galaxy.
“We're particularly interested in seeing the hydrogen gas in galaxies at an earlier period in the Universe's history,” says Dr Staveley-Smith. “With ALFA we may be able to see up to a billion light-years into space [out to a redshift of 0.1]. At that distance we're seeing galaxies that are younger than the ones we see in our local neighbourhood today.”
“We think that in earlier times there was much more hydrogen gas around. How quickly did it get turned into stars? Why are some galaxies more efficient than others at making stars? Those are the sort of questions we'd like to answer.”
Arecibo's large collecting area is particularly well-suited to pulsar studies.
Steve Torchinsky, ALFA project manager at the Arecibo Observatory, says the new device will make it possible to find many new pulsars and will improve the chances of picking up systems that are very rare or not detected so far, such as a pulsar orbiting a black hole.
Finding more pulsars will also help answer basic questions about how pulsars work – for instance, how long they keep giving off pulses.
The Arecibo Observatory is managed by the National Astronomy and Ionosphere Center (NAIC) at Cornell University in Ithaca, New York. The NAIC commissioned CSIRO to build ALFA following the success of a similar ground-breaking instrument CSIRO had designed and built for “The Dish” – its own Parkes radio telescope.
That instrument, called the Parkes multibeam receiver, increased the Parkes telescope's view 13-fold, making it practical for the first time to search the whole sky for faint and hidden galaxies.
It was also used for extremely productive searches for pulsars, finding them at the rate of one for every hour of observing. As a result, most of the 1400-plus pulsars we know of have been found with Parkes.
Highlights of the Arecibo telescope's career include finding the first pulsar orbiting another neutron star, measuring the rotation rate of Mercury, and investigating reports of ice craters on the Moon.
The telescope has also been used to search for signals from extraterrestrial civilisations, and has featured in the movies Goldeneye and Contact.
Arecibo Observatory is a facility of the National Astronomy and Ionosphere Center, which is operated by Cornell University under a cooperative agreement with the National Science Foundation.
Broadcast footage (Betacam SP) of installation and testing of the ALFA instrument Available from Kate Scott, CSIRO Publishing: 03-9662-7591 (office) 0410-567-612 (a.h.)
For more information
- Professor Brian Boyle, Director, CSIRO Australia Telescope National Facility 02-9372-4301 (office) 0418-882-166 (mob.)
- Dr Warwick Wilson, Head of Engineering, CSIRO Australia Telescope National Facility, 02-9372-4324 (office) 0400-492-855 (mob.)
- Dr Lister Staveley-Smith, Head of Astrophysics, CSIRO Australia Telescope National Facility, 02-9372-4271
- Dr Steve Torchinsky, Project Manager for ALFA, National Astronomy and Ionosphere Center, (Located at Arecibo Observatory, +1-787-878-2612, extension 305. Arecibo is 16 hours behind Australian Eastern Standard Time.)
- Mr Graeme Carrad, CSIRO Project Manager for ALFA. (Visiting Arecibo Observatory, +1-787-878-2612, extension 349. Arecibo is 16 hours behind Australian Eastern Standard Time.)