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Another milestone for KAT-7 telescope

29 September 2011

The Square Kilometre Array South Africa team have reached another milestone with the completion of the seven antennas of the prototype KAT-7 and the delivery of the telescope's first astronomical image.

South Africa, allied with eight other African countries, is competing against Australia (allied with New Zealand) to host the €1.5-billion Square Kilometre Array (SKA), an instrument 50-100 times more sensitive and 10 000 times faster than any radio imaging telescope yet built.

The KAT-7 is a prototype for the MeerKAT radio telescope array, an 80-dish precursor instrument for the SKA, being built by the SKA South Africa team on the Karoo Astronomy Reserve outside the small town of Carnarvon in the Northern Cape province.

First astronomical image

Last month, SKA South Africa announced that all seven of the KAT-7's dishes had been fitted with "cold" radio receivers, signaling the successful completion of the telescope antennas.

The first astronomical image – of the galaxy Centaurus A, whose intense radio emission is powered by a massive black hole in the centre of the galaxy – has already been made using cold receivers on all seven KAT-7 dishes.

According to SKA South Africa, the resulting image was much more sensitive than a preliminary image made with just four of the KAT-7 dishes fitted with un-cooled receivers in 2010.

"The radio receivers and all their components are cooled to about 70 Kelvin (minus 203 Celsius) in order to reduce the 'noise' which is inherent in all radio (and TV) receivers," SKA South Africa said in a statement. "This allows the telescope to see much fainter objects than it would if the receivers and 'feeds' operated at room temperature and were not cooled."

'Early science' for the MeerKAT and SKA

The improvement would allow the KAT-7 to perform "early science" in preparation for the MeerKAT and the SKA.

"These preliminary observations will be focused on the needs of the MeerKAT large survey projects, and include imaging of nearby galaxies and work on radio transients and pulsars, for which KAT-7 is well suited."

The KAT-7 is testing technology for the MeerKAT, which is in its early construction phase and is due for completion in 2016.

The MeerKAT, besides being an important step towards the realization of the SKA, will be among the most powerful telescopes in the world in its own right, providing African scientists and engineers with a cutting-edge instrument for revolutionary science and technology.

"This latest milestone in the development of the KAT-7 telescope has again been achieved on schedule," said MeerKAT project manager Willem Esterhuyse.

Esterhuyse commended the technical staff on the site – Siyabulela Tshongweni, Sibusiso Wakhaba, Andre Walker and Matthys Maree – all of whom have been trained in their special high-tech skills by the SKA SA project.

The international science funding agencies and governments involved in the international SKA consortium are due to announce the winning bidder for the SKA in 2012, with construction likely to start in 2016 and take place in phases over several years, with completion by about 2022.

SAinfo reporter