LBA Correlator & Operations LBA’05 Ops mtg Hobart 8 Feb 2005 Tasso Tzioumis

Correlator Operations Part-time (3 days/week) correlator operator –Gary Scott ( 3 year term appointment) –Flexible hours; present most week days –Absentee correlation - most Observns –PIs still encouraged to come and correlate, especially for “special” observations –Also assists with tape handling –Preliminary check of data in AIPS ATLOD - load data Plot and inspect visibilities and spectra (VPLOT, POSSM) Plots on experiment FTP area - web accessible –Further checks? (FRING, ANTAB….)

S2 Tapes ~ 1600 tapesets on web tape list ~ 1200 tapesets are LBA (+ CA VSOP) ~ 1100 tapesets in unreleased observations!!!! 30-50% in pulsars (v041,v088,…) Only 16 observations never correlated (100 sets) + 10 partially correlated. Problems or specials? –Will contact PIs but many obs are old Uncorrelated backlog mainly eliminated Recent observations correlated quickly

Tape release? Need tapesets /session Re-using recent observations (e.g. V131) Need to “free” more tapesets PIs need to inform us when release ok Data Quality checks at correlator. –Sufficient to release tapes?? –What other checks PIs want? –Define time limits?

Correlator issues Tape release S2 transport/tapes unreliable –Synch lost more often –Old tapes worse –Transports aging –S2 Electronics maintenance problematic –  Correlation more “labour-intensive” and slower –Tape aging --> unplayable old observations?

Correlator lifetime? LBA correlator and S2s aging fast No S2 support from Canadians May need to “cannibalise” units to fix others –Limited correlator inputs? –Replace S2s at observatories with disks? –Develop disk-->tape copying? (eVLBI project) Will limit flexibility and efficiency Projected S2 correlator life ? –~ 3 years? to match eVLBI developments?

Online archive LBA archive ~ 650 CDs –Total content < 400 GB - one disk! –Need to “weed” recorrelations Online availability? –“raw” rpfits files? (weeding still needed) –Metadata required? (logs, calfiles?, corr model?) –Online as AIPS multisource fits? FRING, Cal files? Usefulness of online archive?? –Worth the effort and how much? –Propose project?