First antenna installed at Karoo site

Tuesday, July 21, 2009

Pretoria - South Africa's new radio telescope in the Karoo has reached an important milestone with the installation of the first telescope dish near Carnarvon in the Northern Cape.

According to a statement released by the Square Kilometre Array (SKA) South Africa Project Office, the first antenna is part of KAT-7, a seven-dish prototype interferometer array.

A radio telescope is a very sensitive receiver of radio waves. It has two basic components to help decipher the meaning of the radio waves that it detects.

A dish-shaped antenna is pointed to the sky to collect the radio waves. Since the strength of the radio waves that reaches the earth is very weak the collecting area is large.

The curved surface of the antenna then reflects the radiation to the focus point of the dish, where it is received by a metal horn and fed to a sensitive radio receiver.

The receiver then amplifies the radio signal and digitises it - turns it into numbers - so that it can be stored in a computer.

This information is then processed with the help of computers, to help make sense of the strings of numbers, which astronomers turn into pictures.

Each of these numbers represents information from a specific point in space. Astronomers often assign specific colours to these numbers according to the amount of information they represent.

They then combine the colours to make a picture so that the information can then be seen. These pictures inform astronomers about the characteristics of the objects in the universe.

Meanwhile, the construction and commissioning of the full MeerKAT array (consisting of 80 dishes) will also follow at the same site in the Karoo.

"A high speed data network will link the telescope site in the Karoo to the control centre in Cape Town. The telescope will be commissioned in 2013," reads the statement.

The MeerKAT is an important precursor instrument to the much larger SKA that will consist of about 3 000 antennas.

South Africa is currently in a race against Australia to be selected as the preferred site for the SKA. A final decision on the SKA host country is expected in 2012.

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