lba correlator & operations lba’05 ops mtg hobart 8 feb 2005 tasso tzioumis
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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 80-120 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?