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3rd January 2008  MJI's office  11:30-12:35

Present:          STH, PSB, MJI, DWE, JRL
Apologies:        NAW, EGS, MR, RGM

Agenda
------

1.  Actions from last meeting
2.  Comments on WFAU minutes
3.  Recent meetings/visits
4.  Data archives update
5.  Optical processing update
6.  WFCAM news
7.  VISTA news
8.  ADASS 2007
9.  AOB


Minutes
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1.  Actions from last meeting

MR   has not advertized the illumination correction information - ongoing  <<<<

STH  has not checked the advertized illumination correction information and 
     update the relevant section in the calibration paper - ongoing        <<<<
     
MR   has not yet performed the backup verification tests using 4 old LTO 
     tapes - ongoing                                                       <<<<

ALL  still providing comments on photometric calibration paper - ongoing   <<<<

DWE  switched off the database server on apm1 and will remove the related 
     files at the next Windows update.

MJI  has reviewed the user accounts on the APM cluster.

ALL  have sent in reports for November and December to STH by 3rd January.

JRL  has contacted AAT and data transfer has now resumed.

JRL  still checking why pipeline catalogue software and toolkit give 
     different results in a few specific cases - ongoing                   <<<<

JRL  has written a first draft letter of support to Omar Almaini and Phil 
     Lucas regarding future of UKIRT/UKIDSS. This needs a few more tweaks 
     and will be circulated within the group - ongoing                     <<<<

STH  has not fed back comments on Plone/HTML websites - ongoing            <<<<


2.  Comments on WFAU minutes

NCH has requested a CASU account on djedefre to pick up the WFCAM newtork 
transfer efficiency issue again.  (As it happens, UKLight is down this 
morning due to a broken fibre in Middlesbrough.)


3.  Recent meetings/visits

Several from CASU attended the recent UKIDSS workshop in Garching.  Items 
arising from this are in the WFCAM and VISTA sections.


4.  Data archives update    

AAT:
JRL noted that the AAT archive transfers were started again and are now up
to date bar a bit of squishing.

ING:
transfers continue seemlessly as usual.  Data to the end of December 2007 
are currently being checked.

WFCAM:
the remaining week or so of 07B data has not yet been shipped.

UKIRT:
no change

MJI asked JRL if he could fill in the EVO census of data holdings and
archives questionnaire (deadline 20th January).                            <<<<


5. Optical processing update 

No change


6.  WFCAM news

MJI noted that the current plan is to transfer all WFCAM 08A data via the 
Internet.  The desirability of assorted tests during January was raised
again - the remaining WFCAM data for 07B would be a good starting point.

The standard processing of WFCAM 07B data up to and including 24th November
is complete.  The reprocessing to reduce the parquet floor effect is about
a week behind; whilst the remaining week or so of 07B data is not yet
available for processing.  Checking and detector zero-point (re)calibration
is complete up to the 16th November and all 07B processed data prior to this
point has now been flagged as ready to copy.

There followed a short debrief on the UKIDSS meeting focussing on feedback
from users at the meeting and their wish list for improvements.

A few regions show either poor background subtraction or artefacts in the
background - a good example being the Orion complex particularly the M42 
nebula.  At the UKIDSS meeting Phil Lucas encouraged NCH to dig out an 
example of this from the GCS.  MJI had looked at this after the UKIDSS 
meeting and found that most of the problem (apart from the known ancient
cross-talk bug issue) was caused by the decurtaining stage introducing
a "Maltese Cross" pattern in the background.  This is a known feature of
the decurtaining algorithm that occurs in rare cases where the strongly 
varying background interferes with the curtain fixing estimator.  MJI
tried out a simple fix that seems to do the trick and asked JRL to implement
a test version of this in the pipeline for assessment on other tricky 
fields.                                                                    <<<<

The current sky estimation strategy generally works well but there are a 
few specific cases where problems occur.  After discussions with AJA both
prior to and during the meeting a simple method of alerting the pipeline to 
such cases was agreed on and will be implemented for future observation 
MSBs when required.  This will hopefully get around the majority of the
cases where the pipeline is trying to second guess the best strategy
without full prior knowledge.

The desirability of elliptical apertures for galaxy photometry was raised
- interesting since that was what we originally were going to do before a 
majority voted for circular aperture photometry.  The obvious compromise
would be to stick with the current fixed circular apertures and solely use
elliptical apertures for Petrosian, Kron and Hall measures.  We await the
outcome of the prioritised UKIDSS wishlist (and upcoming grant review) 
with interest.

The GPS folk want better photometry in nebulous regions, both from a "point
source" detection and flux estimation point-of-view.  At the meeting we
noted that using a smaller scale background tracker was the simplest thing
to try out, but whether this will really deal with the problem is still
a moot point requiring further testing.

Assorted deblending issues were raised ranging from too little (occasionally
obvious pairs of sources are not deblended - see earlier action) to too much 
(large galaxies getting split and subsequent Petrosian photometry not being 
reliable).  One can only conclude that on average deblending must be about 
right.

Desirability of full iterative PSF model fitting and Sersic profile fitting
(presumably in both cases only for objects/fields worth bothering with since
this will be seriously CPU intensive).  This has always been in the long
term development plans but has not been completed yet.
  
Finally, STH noted that some users were uncertain how to make best use of 
the processed flat file access and in particular were still uncertain about
certain aspects relating to astrometry and photometry.  After a brief
discussion it was felt that although all the relevant information was
available on the CASU plone site and via emailing casuhelp if required, a 
few specific links in the catalogue information page pointing to the relevant 
technical pages would be worthwhile.  STH was tasked to make it so.        <<<<


7.  VISTA news           

VISTA:
The last we heard is M1 will be accepted in factory at end of February.

We received an alpha release of CPL 4.1 which allows use of compressed
FITS files; however PSB is having problems building it.

MJI, JRL, PSB as well as JPE attended UKIDSS workshop in ESO in Dec; as
well as WFCAM results, this was an excellent opportunity to discuss
various VISTA issues with ESO staff.  It seems the Paranal pipeline computer
is delivered but not installed and will be set to not analyse science data.
There are some worrying unsettled issues regarding the timely delivery
of VIRCAM data to the UK.  On the ongoing request for N118 filter data,
JPE reports that he doesn't have machine-readable version.

JRL (in particular) has further analysed linearity data from the July
engineering run - a report is in final draft.  MJI suggested that finishing
this off should have high priority.                                        <<<<


8.  ADASS 2007

All were asked to review the printed copy of the ADASS 2007 proceedings
for obvious errors. This needs to be done by the end of the month.         <<<<

9.  AOB

MJI noted that the upcoming grant review and asked for contributions for
the main themes to be presented.                                           <<<<

MJI pointed out the much improved, including mains power supply and general
tidied up and rearranged, store/computer room.  Related to this PSB noted 
that we were still awaiting a quote for the partition for the main room.

MJI asked STH to help review our potential involvement in the PLATO 
mission assessment study for the ESA Cosmic Visions (2015-2025) programme. <<<<


Continuing Actions
------------------

MR   advertize illumination correction information

STH  check the advertized illumination correction information and update
     relevant section in calibration paper

MR   perform backup verification test using 4 old LTO tapes 

ALL  provide comments on photometric calibration paper

JRL  check why pipeline catalogue software and toolkit give different 
     results in a few specific cases
 
JRL  draft letter of support to Omar Almaini and Phil Lucas regarding future 
     of UKIRT/UKIDSS and circulate within group

STH  feedback comments on Plone/HTML websites


New Actions
-----------

JRL  reply to EVO questionnaire by 20 January

JRL  implement decurtaining modification in test mode

STH  place more links on Catalogue Generation and Photometric Calibration 
     Plone pages

JRL  finalise and issue VIRCAM linearity report

ALL  review printed copy of ADASS 2007 proceedings by end of January

ALL  be ready to contribute to presentations for grant review

STH  review possible involvement in the PLATO assessment study
MJI