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Advancements in VLBI and eVLBI Operations: LBA Transition and Network Connectivity

This report highlights the evolution of the Long Baseline Array (LBA) operations and the transition to enhanced eVLBI capabilities. It discusses the move from tape-based correlation to disk systems and software correlators, successes in eVLBI trials, middleware developments, and improved international connectivity. The report also addresses operational challenges, including scheduling and equipment issues, while showcasing promising statistics and successful real-time fringe checking. Key collaborations with institutions like Swinburne and Curtin are emphasized, along with the importance of user accessibility and data transfer enhancements.

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Advancements in VLBI and eVLBI Operations: LBA Transition and Network Connectivity

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  1. VLBI Report LBA Operations & eVLBI Tasso Tzioumis ATNF May 2008

  2. Operations - transitioning • Evolution: • S2 tapes + LBA correlator - Stopped in 2007. • Disk-system + software correlator - Main user system • eVLBI - in development. Already offered to users. • Software correlation • Contracted to Swinburne from 1 October 2006 (2 years) • Worked very well - no major problems • May substantially transfer to Curtin in 2008 • Movement of key people • Under negotiation with Swinburne & Curtin • Public Wiki for all LBA observations • Schedules; setups; logs • Remote VLBI observing tested - Mp fully remote

  3. LBA Statistics 2007 • Failures: • Parkes: almost all due to high wind • Ceduna & Hobart: Windstows and some power problems • Tidbinbilla: Some config problems (personnel change) • ** High success rate -- real-time fringe checking **

  4. Network connectivity • AARNet3 Regional Network to ATNF antennas • 2 x 1 Gbps connectivity for each ATNF antenna • 3rd 1 Gbps link for lightpaths to Europe (EXPReS) • 10 Gbps (x multiple wavelengths) backbone • Hobart 1 Gbps to UTas operating • Bass-Strait link still very limited. • Correlator connectivity: • Swinburne 1 Gbps “almost” there (2 years….) • Curtin links planned • Good connectivity to Europe • Data transfers disk-to-disk to Bonn correlator • Have avoided disk shipping • 1 Gbps lightpaths to Europe! (see eVLBI) • Better international connectivity than within Australia!!

  5. eVLBI - Oz developments • Pk-At-Mp eVLBI Longbaseline Array (PAMELA) • March 2007 - initial development: • Parkes CPSR2 30-node cluster for software correlator • Successful test observations Pk-At-Mp @ 256 Mbps • Limited observations with Hobart at 128 Mbps • Circinus X-1 detected at 18 & 3 cm -- • Paper published within weeks!! • Further developments - 2007-8: • Improved cluster connections - new nodes • 512 Mbps capability developed & offered to users • 1 Gbps tests successful (Pks-ATCA) • In progress: • New APSR cluster to improve processing capabilities

  6. eVLBI - International • EXPReS tests: • July 2007: Mopra; Shanghai; European telescopes; • JIVE hardware correlator • Longest eVLBI baseline (Mp-Darnhall) • Huge international publicity!! • October 2007: Mp-ATCA-Pks to JIVE • 3 x 1 Gbps dedicated lightpaths! • 12 hour hardware correlation at JIVE @ 512 Mbps • Paper on SN1987A submitted!! • Planned for June 2008: • ATNF antennas + Shanghai(China) + Kashima(Japan) • Correlation at Parkes on Swinburne software correlator • Extremely valuable connections to networking world • Internet2 IDEA prize won!! (Shaun Amy) • Science + Publicity!

  7. LBA - Current Status • User facilities: • Disk recording up to 512 Mbps / 1 Gbps (ATNF) • May require justification for v. high rates • Software correlation at Swinburne/Curtin • PAMELA eVLBI at 512 Mbps • 1 Gbps tested but limited • Fast response ToO and NAPA proposals possible • eVLBI (3 antennas) for quick look • Disk recording for imaging • Mk5b recording supported • International compatibility • Geodetic VLBI with all ATNF antennas (new) • LBA data can be correlated at Bonn!

  8. ATNF operations model & VLBI • Integrated scheduling with ATNF schedules • Main impact from proposed restricted receiver changes at Parkes. • Loss of flexibility • Proper-motion projects (almost) impossible • Move to shorter VLBI/eVLBI blocks? • minimise disk swaps & transfer over network? • Some issues with Tid scheduling • last minute schedule changes/swaps? • Cost and Impact of VLBI • Refer to future ops discussion forum submissions • http://www.atnf.csiro.au/observers/planning/discussion/outputThread.php?id=43

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