| Mosaic of nine single-polarisation ASKAP
beam patterns, using weights that optimise the sensitivity of the beam. Each
pattern has been placed in the location reflecting its offset from the centre
of the field. Systematic variations in the side-lobe structure can be seen in
the offset beams. These sensitivity patterns were measured using holography
with two of the BETA antennas, one acting as a reference and the other scanning
over a 15 x 15 square grid with 0.6 degree spacing. This measurement technique
will be used to test other beamforming algorithms that constrain the symmetry
and side-lobe levels of a formed beam.
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