KAT-7 antennas completed and producing images


The prototype for the MeerKAT radio telescope, KAT-7, has reached a major milestone with the successful completion of all the telescope antennas.

The MeerKAT is the precursor array for the world’s largest telescope, the Square Kilometre Array (SKA). SA is currently bidding against Australia to host the SKA.

The KAT-7 telescope has achieved a major milestone, since all seven of the dishes have now been successfully fitted with “cold” radio receivers, signalling the completion of the antennas, according to the KAT-7 project team.
“The first astronomical image has already been made using cold receivers on all seven KAT-7 dishes. The radio galaxy Centaurus A, whose intense radio emission is powered by a massive black hole in the centre of the galaxy, was selected for this purpose.”

It adds that the resulting image is much more sensitive than the preliminary image made with just four of the KAT-7 dishes fitted with un-cooled receivers in 2010. The improvement is due to both the cooling of the receivers and the availability of all seven dishes of the array.
“The radio receivers and all their components are cooled to about 70 Kelvin (-203º Celsius) in order to reduce the ‘noise’, which is inherent in all radio (and TV) receivers. 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.”

The team says cooling improves the sensitivity of the receivers by more than a factor of 2.5, which in turn reduces the observation time to achieve a given image quality by more than a factor of six.
“This improvement in performance will allow KAT-7 to perform early science in preparation for the MeerKAT and 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.”

KAT-7 tests technology for the MeerKAT, which is in its early construction phase and is due for completion in 2016.
“This latest milestone in the development of the KAT-7 telescope has again been achieved on schedule. The technical staff on the site: Siyabulela Tshongweni, Sibusiso Wakhaba, Andre Walker and Matthys Maree, have worked with great commitment, together with the rest of the SKA SA team, Stellenbosch company EMSS, and Cape Town company Tellumat, to achieve this goal. All four technicians have been trained in their special hi-tech skills by the SKA SA project,” says MeerKAT project manager Willem Esterhuyse.

In August, the MeerKAT telescope passed its first design review with flying colours, according to a panel of international experts.

It will be the largest and most sensitive radio telescope in the southern hemisphere, until the completion of the SKA in 2024, and will have 64 dishes.

The SKA SA project office recently said the KAT-7 telescope is reaching engineering completion. Commissioning and learning will be ongoing and an operational baseline will be established by the end of the year. With the completion of KAT-7, the project team will focus on the construction of the bigger MeerKAT.