Layout of antennas on the ground
A continental footprint
The total collecting area of the SKA will be one square kilometre, or 1,000,000 square metres. To acheive this, the SKA will use 3,000 dish antennas, each about 15 m in diameter as well as two other types of radio wave receptor, know as aperture array antennas. The antennas will be arranged in five spiral arms and the dishes will extend to distances of at least 3,000 km from the centre of the long baseline array.
The antennas of the SKA will extend across a continent.
The spiral layout has been chosen as this gives many different lengths (baselines) and angles between antennas resulting in very high resolution imaging capability. The perfect layout would be a random arrangement that maximises the number of different baselines and angles between antennas. However the practicalities of construction as well as linking the antennas together with cables mean that the spiral configuration is the best trade off between image resolution and cost.
The central regions in Australia and in South Africa will contain cores each 5 km in diameter; one for each antenna type. Fifty percent of the collecting area will be within the central cores. The aperture array antennas will extend to about 200 km from the core regions. In Southern Africa the dishes will be positioned in distant stations out to at least 3,000 km.
Also in this section
