An Overview of The LBA

Very Long Baseline Interferometry involves a network of telescopes in Australia and overseas. Until 1997, this network had been supported by the individual institutions operating each telescope via a cooperative arrangement.

Under the 1997 Major National Research Facilities program the VLBI network was upgraded and agreement was reached between ATNF and the University of Tasmania to operate the network as a National Facility. Auckland University of Technology, which runs the Warkworth observatory, joined the LBA via an MoU in 2011.

From 2006 the University of Tasmania telescopes at Hobart and Ceduna have been operated under a service agreement between UTas and ATNF.

The National Facility part of this network is the Australian Long Baseline Array (LBA), run by the VLBI Group and collaborators at the ATNF and participating institutions. The Long Baseline Array (LBA) utilises the ATNF telescopes (Parkes, ATCA and Mopra), and the Hobart and Ceduna antennas operated by the University of Tasmania to observe in VLBI mode. Other telescopes may also be requested for special observations. Note that the Tidbinbilla 70-m antenna may be available only for short periods. The Warkworth 12m and 30m telescopes operated by SpaceOps NZ (which took over operation from the Auckland University of Technology) may also be requested. The Hartebeesthoek 26-m telescope, operated by SARAO, is also often available for LBA observations. These facilities are offered on a best-efforts basis and to observations for which their use significantly adds to the likely science outcomes. Specific system availability may be dependent on availability at individual antennas.

Unlike The Australia Telescope Compact Array, where the data from each antenna is correlated as it is collected, VLBI is carried out by observing at various telescopes in the network relatively independently of each other. The raw data is transported to a correlator facility and correlated there in real time. Since 2015, the main VLBI correlation for the LBA is done at Pawsey Centre for SKA Supercomputing using the DiFX software correlator.

The LBA is also available for observations in conjuction with East Asian VLBI Network (EAVN) and the European VLBI Network (EVN).

To carry out VLBI observations with the LBA, proposals must be submitted to the ATNF in the same way as proposals to use other telescopes run by the ATNF.

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