The first interferometric tests carried out on three Mk II phased array feed receivers recently installed at the Murchison Radio-astronomy Observatory (MRO) have confirmed the in-the-field performance of the newest receiver systems developed for ASKAP.
“This is a really significant result, especially at this early stage of Mk II deployment,” says Ant Schinckel, ASKAP Project Director, “It confirms the efficiency of the integration tests we run on the systems in our Sydney labs and gives us a good indication of how well the components perform on site."
The Mk II PAFs installed on ASKAP Antennas 4, 5 and 12 were used to observe the radio galaxy Virgo A, some 50 million years away. Fringes were achieved on the three baselines between these antennas, followed soon after by phase closure.
The results are a significant step towards the full ASKAP telescope, and achieved so quickly largely thanks to the valuable experience gained during commissioning of the Mk I PAFs (the six-antenna telescope also known as the Boolardy Engineering Test Array, or BETA).
Phase closure is an excellent end-to-end demonstration that requires almost all of the basic telescope system to be working, including antennas, receivers, digital electronics, frequency and timing system and software. The team will continue to work on stabilising the systems, consolidate the software and make similar observations routine.