6th August 2008 APM comfy chairs 11:30-13:05 Present: RWA, MJI, JRL, PSB, MR, DWE, EGS, NAW Apologies: STH, RGM Agenda ------ 1. Actions from last meeting 2. Comments on WFAU minutes 3. Recent meetings 4. Data archives update 5. Optical/NIR processing 6. WFCAM update 7. VISTA update 8. AOB Minutes ------- 1. Actions from last meeting STH has not finished checking that the Plone astrometry technical pages are correct - ongoing <<<< MJI has tried to acquire the transmission curves for the VIRCAM N118 filter but life is too short ...... JRL has revived the changes log web page for the WFCAM pipeline. This can be found on the internal pages at http://casu.ast.cam.ac.uk/surveys-projects/wfcam/software-changes/ MJI has found out more regarding the VIRCAM commissioning plans including updated schedules and work plan STH has not included the graphic showing the size of the photometric radial distortion correction in the Plone technical pages - ongoing <<<< MJI has checked the connections on an LCD TV to see if displaying from a laptop works ok. The external width of a 37" TV is about 40", which is the largest that will fit comfortably on the tables planned for the meeting area. MJI has tried to order some suitable tables for the meeting area, but has encountered the University Department of Bureaucracy - ongoing <<<< MJI has obtained the VISTA schedule (see above) STH have investigated photometry in regions of high nebulosity in Eta-Carina MJI data from HawkI and obtained some impressive results JRL has not produced a web page of HawkI publicity for CASU - ongoing <<<< MJI has updated the pipeline toolkit on the Solaris cluster MJI has investigated ways of demonstrating photometric corrections for flat file users and has decided to provide a simple programme that starts from a catalogue FITS file and outputs fully calibrated and corrected magnitudes in an ASCII file. JRL deferred deciding on a flipping jitter telecon with JAC for now since several other items have since cropped up (see later) JRL has written a script to flag summit-rejected MSBs during raw WFCAM data ingestion. MR has yet to include this in the ingestion script. <<<< MJI has implemented trial MSBTid logs for 08A, this will be used in anger for 08B data. 2. Comments on WFAU minutes Not many comments other than we noted the usual saga with the air conditioning - good job its cold in Edinburgh; and the announcement of the release of DR4, sans GPS and UDS, on 4th July. 3. Recent and upcoming meetings MJI had a day out in London on July 8th attending the meeting where STFC presented the results of the Programmatic Review. In addition to EGS and NAW, MR and JRL will attend the Cambridge VOTC workshop in early September. JRL pointed out the upcoming ADASS late autumn meeting in Quebec, ALL to consider submission of abstracts deadline is August 15. <<<< MJI also noted the planned Science from UKIDSS-II meeting at the RAS on 15-17 December. 4. Data archives update The remaining photographic plates left at the IoA are being rationalised into one office prior to being removed to the off-site storage facility. With the rearrangement and installation of more computer kit in the computer room, we have a DVD/CD-ROM cabinet too many to comfortably fit in the space. RWA will remove the JKT DVD/CD-ROMs from the computer room and free up one cabinet which will then be removed to the IoA annex. The JKT data is already on disk and backed up on LTO tape. <<<< MJI asked if the internet transfers were included in the ING archive backups. Although these are backed up in monthly batches as they arrive it was felt they should now be included in the general ING archive backup. EGS will implement a backup scheme to include the internet transferred INT/WHT data on LTO4s now that we have two independent LTO4 library units <<<< PSB already found a suitable supplier of LTO4 tapes and will order some more now he has got his order book back. <<<< JRL reported that he is in the middle of revamping the UKIRT archive to fix a few long standing problems with headers and legality of PHUs. AAT data continues to arrive in roughly monthly chunks where the transfer is initiated manually, but its such a small amount of data that its not worth doing any other way at this stage. All of the WFCAM raw data is now back online after the fault with the recalcitrant RAID unit was finally traced and fixed - its SP was F'd. Raw data tape backups for all of 08A have been made and are sitting in a modest pile under MJI's desk. LTO2's only store ~5 nights of compressed data per tape (hence the large pile) so we will switch to LTO4's for 08B where we expect to get ~20 nights on a tape. Although 08A's tapes make a great footstool they need removing to the out-of-building store. <<<< 5. Optical/NIR processing JRL, STH and MJI had a meeting with a posse of Exeter PhD students and postdocs lead by Mark McCaughrean to discuss the CASU-processed HAWK-I JHKs data on Eta Carina. In addition to the beautiful 2D images, and exquisite photometry in nebulous regions we also managed to improve the astrometry systematics to < 20 mas over the whole array using our usual ZPN WCS. JRL is investigating further improvements to the 2D processing and when that is finalised we will switch to generating catagloues from mosaic tiles of the 4 dither stacked detectors per pointing, rather than from individual detectors, which should help with the non-uniform exposure maps caused by the large dither patterns used. NAW, EGS and MJI attended an EGAPS meeting in Warwick on 24th June. EGS and MJI reported there that we have finished processing all the IPHAS data up to end of 07B and are still awaiting final decisions on the U-band and HeI-band filter offsets for the UVEX equivalent. 6. WFCAM update MJI reported on an email received from AJA about the possibility of overcoating the WFCAM secondary mirror with gold rather than silver. If this goes ahead it shouldn't have much impact on the throughput in any of the bands at the ~1% level, but it would make sense to double check the colour equations. The idea of a telecon with JAC before WFCAM 08B commences was discussed. There are several issues that could profitably be dealt with including: a resume of the jitter flipping strategy, offset skies and data self-description; pipelines running at JAC; technical updates; fast flat file access and so on. MJI to sort out topics and a suitable time/date around the beginning of September for a telecon with JAC. Attendees from our side likely to be MJI, STH, JRL and MR, no doubt at Jim's place. In return Jim will provide the refreshment. <<<< As reported earlier the reluctant raw data disk was finally fixed, and in the same burst of creative energy, this rarely used disk was switched over from its own fibre channel to a shared channel fibre loop, thereby freeing up a fibre channel for a recently acquired 14 TByte RAID system. The GPS astrometry glitches affecting ~200 files over the 05A-07B period noted in the previous minutes were fixed and have been re-transferred by WFAU. There have been a one or two examples of 08A data (eg. Orion for GCS) where a strange sky subtraction decision was made by the pipeline. These were fixed manually after they were reported to us by NCH. MJI and JRL discussed a couple of minor changes to the special case object masking sky creation strategy to prevent this happening in the future. JRL will implement. <<<< Phil Lucas is going to supply a list of GPS data within regions of high nebulosity which would benefit from recataloguing using the recently developed nebulosity filtering option. This methodology is undergoing final trials and will eventually be incorporated as an option within the cataloguing software. MJI and MR have been exploring some software updates in the general toolkit software that allow things like internal dribbling of interleaved frames to minimise the "hedgehog" PSF problem; use of frame magnitude zero-points to monitor and correct for variable throughput when mosaicing; and different interpolation options for stacking and mosaicing. The latter, in particular, will be needed for VISTA image processing. 7. VISTA update The big news is the VISTA first on-sky photons on VIRCAM. The first FITS file with sky images on was received at CASU on 2nd July via network from Edinburgh off a disk hand-carried from Paranal. Since then a steady stream of test data and on-sky data has been received, some directly in small doses from Paranal, but the majority via hand-carried disks. As expected there were the usual teething problems with WCS's and various telescope/camera parameters and observing templates, but these have quickly been sorted. Sufficiently so, such that recent frames have included enough calibrations and the odd on-sky dither sequence to enable assorted preliminary science checks to be made. As expected the WCS is well described by the ZPN projection and our measured distortion coefficient is within about +/-1 of the predicted value of 42. Although we are awaiting remaining optical tweaks before doing further analyses, after calibrating some dither stacks against 2MASS the systematic astrometric residuals are already at the 50 mas level over the whole array. A dither sequence in the Eta Carina region has sufficiently good image quality (~1 arcsec) and sufficient bright stars being shifted around the arrays, to enable a thorough search for persistence and cross-talk artefacts. So far, in spite of our best efforts, we have been unable to find any trace of cross-talk and cannot see any significant trace of persistence at a level that would require correcting. Although early days this is extremely promising and makes the 2D image processing aspects more straightforward than they might otherwise have been. Having real on-sky data is helping enormously with the DRL development and fine tuning but we are still desperate for more calibration data to really nail the properties of the camera, especially linearity sequences and twilight flats. In parallel with this we have also been acquiring and installing some VISTA data processing and storage kit. This had already involved assorted changes to the air conditioning placement, rearrangement of what was the storage room and installation of yet more mains supply - this time in the form of 9 (8+1 spare) 16-amp commando sockets. The latter are primarily needed for the recently installed Sun 20-core Blade 6000 system, which will form the backbone of the VISTA data processing here, and for future upgrades for the GAIA data processing kit. In addition to this hardware, we have also procured and installed a 48TB Sun X4500 disk system and another LTO4 tape library unit, both installed in the VISTA rack together with the Blade 6000. Other recent upgrades include the installation of 10 G-bit switches in both computer rooms and, as reported before, both rooms are now on the IoA 10 G-bit backbone. 8. AOB NAW noted that VST science commissioning is scheduled to start mid-2009 with the public science surveys likely to start by the end of that year. EGS raised the issue of releasing the CASU cataloguing software and the rest of the pipeline toolkit, which among other things would raise the profile of the group. MJI was worried, as always, about the amount of implicit extra support and maintenance that this would entail but he and EGS will look further into this and present a cunning plan at the next meeting. <<<< MJI and NAW summarised the current state of play of the CASU rolling grant saga and also our involvement in the PLATO and PrepSKA applications. Continuing actions ------------------ STH check that Plone astrometry technical pages are correct STH include graphic showing the size of the photometric radial distortion correction in the Plone technical pages. MJI continue ordering some suitable tables for the meeting area JRL produce web page of HawkI publicity for CASU New actions ----------- MR install JRL's script to flag summit-rejected MSBs during raw WFCAM data ingestion ALL consider submission of abstracts for ADASS 2008 (deadline August 15) RWA remove JKT CD ROMs from computer room and rationalise storage to free up a cabinet EGS implement backup scheme for internet transferred INT/WHT data and swtich to LTO4 tapes PSB order some LTO4 tapes RWA move 08A WFCAM raw data backup tapes to Obs. store cupboard MJI discuss topics and suitable time/date for telecon with JAC JRL make minor changes to object masking sky estimation strategy MJI assess and if feasible come up with a plan for software release EGS