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Observatories

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Each AuScope VLBI observatory is equipped with a 12.1m diameter antenna designed and constructed by COBHAM Satcom, Patriot Products division. The characteristics are: 0.3 mm of surface precision (RMS), fast slewing rates (5 deg/s in azimuth and 1.25 deg/s in elevation), and acceleration (1.3 deg/s/s).

All three sites will be equipped with dual polarization S and X-band feeds from COBHAM with room temperature receivers, developed at UTAS by Prof. Peter McCulloch. The receiver systems cover 2.2 to 2.4 GHz at S-band and 8.1 to 9.1 GHz at X-band. System Equivalent Flux Densities (SEFDs) are 3500 Jy at S- and X-band. Data digitisation and formatting is managed by the Digital Base Band Converter (DBBC) system from HAT-Lab, and data are recorded using the Conduant Mark5B+ system. Each site is equipped with VCH-1005A Hydrogen maser time and frequency standards from Vremya-ch.

Data Processing

CUPPA1
The CUPPA

Some of the data collected by the AuScope geodetic VLBI array is processed on CUPPA (Curtin University Parallel Processor for Astronomy). CUPPA is a 20 node beowulf compute cluster. Each node consists of a server class PC with dual quad-core processors (Xeon 2.66 GHz), 8 GB of RAM and 1 TB of internal hard disk storage (four nodes have a further 3 TB of internal disk storage each). Additionally, the cluster incorporates external mass storage in the form of five Apple Xserve Xraid chassis, each capable of hosting two 7 disk raid sets (7 x 750 GB). A total disk pool of 100 TB is available to the cluster. CUPPA is networked internally with standard 1 GbE (two ports per node) and with a 10 GbE connection to iVEC, the estern Australian state supercomputing centre.

AuScope data, recorded to Mark5 disks at each of the AuScope antenna sites, are transferred electronically to Curtin for correlation and processing.

For VLBI correlation, CUPPA runs the DiFX (Distributed FX) software correlator, developed by Dr Adam Deller when a graduate student at Swinburne University of Technology's Centre for Astrophysics and Supercomputing (Deller, Tingay, Bailes & West 2007, PASP, 119, 318). DiFX has a global user and developer community and is used for astronomical and geodetic correlation at major facilities in the US, Germany and Australia, as well as minor facilities in Australia, New Zealand, the US and Italy. VLBI correlation on CUPPA is managed by Dr Hayley Bignall (for more information contact Dr Bignall at h.bignall@curtin.edu.au).

CUPPA and its operation has been funded by the NCRIS 5.13 AuScope VLBI project, Curtin University of Technology and the State Government of Western Australia.

CUPPA has its own fan page on facebook, where news on CUPPA operations and upgrades is posted periodically.