From wjs@ast.cam.ac.uk Sun Oct 16 12:31:45 2005 Date: Wed, 21 Sep 2005 14:25:39 +0100 (BST) From: William Sutherland To: Tim Naylor Cc: Tim Naylor , Jim Emerson , Alastair Edge , paj@astro.livjm.ac.uk, pwl@star.herts.ac.uk, Steve Maddox , naw@ast.cam.ac.uk, s.j.warren@imperial.ac.uk, Malcolm Stewart , Mike Irwin , Peredur Williams , Nigel Hambly , Richard McMahon , Andy Lawrence , Simon Dye , Maureen Scott , Simon.Berry@pparc.ac.uk Subject: Re: 3rd VDUC - minutes. ---------------------------------------------------------------- Minutes of 3rd VDUC Meeting, Cambridge, 6 Sep 05: ---------------------------------------------------------------- Present: Jim Emerson, Perry Williams, Nigel Hambly, Malcolm Stewart, Andy Lawrence, Richard McMahon, Tim Naylor (chair), Mike Irwin, Simon Dye, Nick Walton, Will Sutherland, Simon Hodgkin, Alistair Edge, Pete Bunclark. Apologies: Simon Berry , Phil James, Phil Lucas. 1) Report on Actions ---------------------------- FM2-1 : CASU + WFAU to get WFCAM Phase I data into Archive by end March - complete. FM2-2: CASU + WFAU to deliver a "significant amount of data" into Archive by end May. Science verification data to be dealt with ASAP - completed 10 June. FM2-3: TN to contact UKIDSS survey heads to get them to coordinate with Simon Dye and CASU regarding technical details of the MSBs - done. FM2-4: TN to request UKIDSS survey heads to present some results at the next meeting, late June / early July - done. FM2-5: JPE to report outcome of VDFS review in due course - ongoing. FM2-6: All to email JPE with suggestions for review panel - ongoing. 2) CASU progress report: Mike Irwin. ------------------------------------- The ESO pipeline FDR took place in Feb 05, with good results. A lot of effort has gone into the WFCAM summit pipeline. The 5sec exposures have led to a doubling of the data rate to 250 GB/night (close to the expected VISTA rate) , but it is just about keeping up. So far there is 13 TB of raw data , 20 TB processed (divide by 5 after Rice-compression). 0.01% of frames have a channel missing, these are discarded. Internet bandwidth to Edinburgh is good, but to ESO is poor - this may become a real problem for VISTA. >>> Action FM3-1: JPE to talk to ESO about internet bandwidth issue, involving UKLight people if necessary. The processing steps are linearisation (not needed), flat-fielding, 'crud' removal, de-curtaining, then combining. Astrometry looks 'very good' (better than 2MASS), photometry repeatable to few percent. There was a discussion about releases, when is ESO-wide access etc: >>> Action FM3-2: AL to clarify UKIDSS release plan and state average delta-T for observations to appear in archive. Cross talk: this is significant (1% to neighbour channel, 0.25% to second-neighbour), and is immune to stacking (it co-moves with stars). Can (usually) be discriminated by odd morphology. Persistence lasts for several minutes; it does 'stack out' , but has stellar PSF. This probably makes it undesirable to do LAS observations after GPS ones ? 3) Report on WSA: Nigel Hambly. -------------------------------------------------- Problems with infrastructure (air con etc) now sorted. The software is dealing well with scaling / updating issues. Registration is being done via "community" groups. Currently only UKIDSS-testers have access. Lots of feedback has been obtained, leading to bug fixes + improvements. A real-time demo of SQL querying was shown, and worked well. Neighbour tables are already saved , so queries involving neighbours are fast. 4) SV Report: Simon Dye ---------------------------------- Simon summarised results from the Aug.18 Edinburgh meeting. The 'crud' is time-variable so the correction frames need to be up-to-date. With the shorter exposures, readout noise is just outside the '10% increase' aim in Y, and well outside in Z. An estimate of the refractive-optics throughput has been made, and is 45% at Y to 60% at K. Stacked frames from DXS data have been made, and look good except for persistence. 5) 'Cluster collaboration' : Tim Naylor : ------------------------------------------ TN has done some tests of his own "cluster" reduction vs CASU pipeline; astrometry agrees at the 100mas level, probably limited by the "cluster" reduction. The "cluster" photometric results (which use an optimal extraction) appear to go deeper, with smaller uncertainties, but this need to be re-examined when the CASU profile fitting photometry become available, as opposed to the aperture photometry they are currently using. 6) VISTA update ------------------------------- Jim Emerson gave a progress report on VISTA. Things are moving fast - the dome is nearing completion, the telescope structure has been assembled in Texas (awaiting tests), and the IR camera has successfully completed its first cold run at RAL (with eng-grade detectors and a short-nose test configuration). All 16 science-grade detectors have been delivered & tested - well done Raytheon. There are ~ 1% bad pixels , but QE is excellent and other specs are good. The project is still on track for commissioning during 2nd half of 2006, and real science from start of 2007. There followed a discussion about VISTA proposals. It is expected that ESO may issue an AO in approx November (TBC). Therefore: >>> Action FM3-3: JPE to organise meeting in late Sep / early Oct to discuss possible VISTA surveys. 7, 8, 9 Discussions --------------------------- There followed a discussion about when the pipeline/archive will be ready for VISTA data, when data would be released etc, leading to the following several actions: >>> Action FM3-4: JPE and JMS to clarify the possible date inconsistency between pipeline and archive plans. >>> Action FM3-5: CASU + WFAU to get all 2005A UKIDSS data ready for public release by Xmas , and contact TN if they encounter problems which may stop this. >>> Action FM3-6: TN to arrange next VDUC meeting after Xmas. >>> Action FM3-7: VDMT to clarify responsibilities between pipeline and archive for various VDFS requirements (re variable/moving objects etc). >>> Action FM3-8: MJI + PW to send document discussing any "questionable" requirements in URD v3.0 to TN, for circulation to VDUC. >>> Action FM3-9: TN to discuss status of user documents before next VDUC. 10) Astrogrid / Virtual Observatory: Nick Walton. ------------------------------------------------- NAW gave a presentation on VO issues. It is technically possible to access UKIDSS via VO protocols from Cambridge or Edinburgh , but there is a non-trivial snag with authorisation/protection/firewall related issues - a workaround is under development. First trials expected in October, then full connection to UKIDSS in Q1 2006. >>> Action FM3-10: TN to invite NAW to arrange someone to demonstrate working VO access to UKIDSS data at next meeting. Will Sutherland (VISTA Project Scientist) wjs@ast.cam.ac.uk Mobile: +44 7889 396348 Office: +44 1223 337528 Institute of Astronomy, Madingley Rd, Cambridge CB3 0HA.