Collaborative Research Projects in Australia: Radio Astronomy

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Collaborative Research Projects in Australia: Radio Astronomy. Dr. Greg Wickham (AARNet) Dr Tasso Tzioumis Dr Shaun Amy Dr Chris Phillips (CSIRO ATNF). Global Collaborations / APAN 28 th August 2007. Radio Interferometry. Telescopes focus on a source - PowerPoint PPT Presentation


  • Collaborative Research Projects in Australia:Radio Astronomy

    Dr. Greg Wickham(AARNet)

    Dr Tasso TzioumisDr Shaun AmyDr Chris Phillips(CSIRO ATNF)Global Collaborations / APAN28th August 2007

  • Radio InterferometryTelescopes focus on a sourceClosest telescope has delay introducedData streams fed into correlatorFringes are calculated:

    Provides information on structure and position of radio sourceTelescopes focused at different sources no fringes

  • Building an ImageTelescopes maintain focus on source for a period of timeAs the earth rotates more data is collected

    Data fed into correlator

    Similar in concept to time lapse photograph

    Final image is interpolated

  • Visibility of Sources

  • eVLBI StrategyNow1024 Mbps/telescope - 2 x 1GbpsN x 1Gbps to correlators: Swinburne / Curtin --> 10 Gbps circuits?International: JIVE (n x 1 Gbps); USA; Asia

    3 years:CABB correlator at NarrabriMin: 2 x 10 Gbps (8Gbps) / telescopeN x 10 Gbps into Narrabri

  • eVLBI Strategy5 years:ASKAPN x 10 Gbps per telescope to CorrelatorsNew NSW site (Fowlers Gap)Connections to and in WA & NZ

    10 years:SKACandidates are Australia and South AfricaExtreme bandwidth required (up to Tbps)

  • eVLBI Strategy in MotionHuygens TransferVLBI

    EXPReSmilestone in the progress towards SKA.International collaborations are extremely importantStrategic to be involved

    In AustraliaeVLBI is ~ 10% of the ATNF observationsHow is this going to evolve is not clear yetAnd as ASKAP and the SKA come along, there will be bigger sectors of the community involved

  • VLBI - Huygens Space Probe

  • EXPReSData Path:Telescopes to MarsfieldMarsfield to AARNetAARNet to Jive

    Trial:June3 x 256Mbit/sec streamsUsing routed network

    Full Test:October3 x 512Mbit/sec streamsUsing circuitsParkes

  • EXPReS: Trial3 x 256 Mbit / secCombined at MarsfieldTemporary 1G connection to AARNetRouted connection back to JIVERelatively Simple

  • Final Experiment3 x 512Mbit/secDirect patched in SydneyNot to Scale!

  • Square Kilometer Array

  • Thank You!

    Cassini spacecraft left Earth in October 1997 to travel to Saturn

    On Christmas Day 2004, the Huygens probe separated from Cassini

    Started its descent through the dense atmosphere of Titan on 14 Jan 2005

    Using VLBI, 17 telescopes in Australia, China, Japan and the US wereable to accurately position the probe to within a kilometre(Titan is ~1.5 billion kilometres from Earth)

    Need to transfer Terabytes of data between Australia and the Netherlands

    Throughput IssuesLow level packet loss affecting TCPDifficulty in arranging network testingFirewalls

    Work AroundsDeployed dedicated L3 connection to ATNF (Marsfield)

    Problems PersistedMany people involvedTCP Throughput Low level packet loss

    LearningsDifficulty in diagnosing long distance performance issues


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