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1st November 2006  Hoyle Committee Room 10:00 - 12:37

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

Agenda
------

1.  Actions from last meeting
2.  Comments on WFAU minutes
3.  Recent meetings          - ADASS 2006 Tucson
                             - UKIDSS meeting in Nottingham
                             - VDFS UK review
4.  Data archives update     - AAT, ING, WFCAM, UKIRT
5.  Optical processing update- IPHAS release via AG tools
6.  WFCAM news               - 06B news
                             - photometric recalibration
7.  VISTA news               - VIRCAM lab data analysis
                             - CASU & commissioning tasks
                             - VISTA survey management plan & public surveys
8.  AOB


Minutes
-------

1.  Actions from last meeting

JRL  has nearly  implemented the fix to the problem with the UKIRT archive
     (missing header information problem). Only a few modifications to
     scripts need doing - ongoing                                          <<<<

STH  has started combining the data of the supernova remnant image from Albert
     Zijlstra to make a nice colour image. He has now passed on the task to
     Amanda Smith. He has also emailed ING to see if we can obtain their 
     poster directly - ongoing                                             <<<<

STH  has not investigated the effects of stacking on the 2MASS/WFCAM 
     non-linearity comparison - ongoing                                    <<<<

JRL  has come up with a solution regarding the PostgreSQL problems with the
     AAT archive. However, the communication turnaround is slow and holding 
     up the completion of this task - ongoing                              <<<<
     On a related topic, it was pointed out that it has been quite a while
     since any AAT data has been received by CASU. The backlog of data
     not received will stretch to 2 years soon.

MJI  have not emailed the new WFCAM colour equations to DWE and JRL (see
STH  next action) - ongoing                                                <<<<

STH  has discussed the new WFCAM colour equations within the Calibration 
     working group. A calibration scheme using the 2MASS photometry to
     calibrate Y and Z is favoured and will be implmented soon - ongoing   <<<<

RGM  has not finished working on the classification aspect of cross-talk 
     weeding - ongoing                                                     <<<<

JRL  has not added a detection filter FWHM choice as a command line option of 
     the pipeline version of imcore. There was some discussion regarding this
     and the exact task has been clarified - ongoing                       <<<<

ALL  sent in quarterly reports to STH. In the end, these were not used as 
     part of the UK Review.
     
DWE  have not updated the Plone technical pages on astrometry. At the moment,
MJI  the description in the pages agrees with the released data. When the
     astrometry gets updated, then the pages will be updated - ongoing     <<<<

MJI  raised the issue of UKIDSS data release policy at the Nottingham meeting.
     Apparently the JAC web page is not meant to say that the data will be
     released 18 months after observation. It should say 18 months after the
     processed data has been released to the European community. SJW is
     contacting AA regarding this.
     
PSB  requested the latest official VISTA schedule and distributed it

ALL  were happy to accept MJI's choice of venue for the UK Review meal


2.  Comments on WFAU minutes

The deadline of 25 October was noted for gripes from the Survey Heads
regarding 05A reductions. MJI said that only one significant item had come 
to his attention, concerning problems with the crosstalk correction in 
areas of bright spatially variable nebulosity. A logic bug is the culprit 
and a fix is being worked on. It was noted that data with the crosstalk 
correction applied has been available for over a year.

MJI has written a script for stripping out the recalibration parts of the 
FITS headers and putting them in a text file. An example of this has 
been sent to WFAU for comments on format.


3.  Recent meetings

JRL and PSB reported on items of interest from the ADASS 2006 meeting in
Tucson.

FITS: the proposal to have header records of variable length was not
supported. Neither was that to have keywords longer than 8 characters.
WCS: the WCS paper III - representation of distortions that are not 
described by the usual functional forms is well advanced.  This will be 
done via tables (which is the current plan for WFCAM distortion residuals).
Intrapixel sensitivity variations: there was a good talk on this and their
effect on photometry by Kenneth Mighell. MJI asked if anyone in CASU was 
interested in investigating this for WFCAM (and later for VISTA).  He noted 
that Paul Jorden and Derek Ives had done similar measurements on optical 
detectors several years ago and said that he would contact Derek Ives to 
see if there was any WFCAM detector information on this topic.             <<<<

MJI attended a UKIDSS meeting in Nottingham on 13th October. Most of the 
discussion was about the new proposals and nothing much on VDFS issues. The 
current surveys will be resubmitted along with new ones (eg. UHS the UKIRT 
Hemisphere Survey). There was some discussion about where the extra observing 
time would be coming from.  This may have implications for CASU in that 
the fraction of time that WFCAM is used may entail extra processing/year.

The UK VDFS review was held on 24/25 October at Cambridge. This was a 
thorough review of the state-of-play and the plans of VDFS.  Colin Vincent 
from PPARC attended a large part of the meeting.  At some point in the near 
future a written report is expected.  Meanwhile, the verbal summary after 
the meeting was positive.  Various suggestions were made by the review panel 
of which the most significant from a CASU point-of-view was the 
recommendation that the software should be made publically available.  While 
having no major objections to this, CASU are a bit worried that this may 
involve some level of external support of the code, which may become a drain 
on CASU resources.  We will see.


4.  Data archives update     

AAT: No further news

ING: This is now stable. EGS was asked to make a backup of the archive.    <<<<
MJI said that new LTO tapes have been bought for the purpose.

MJI raised the issue of retiring cass36 and cass38 by the end of the year.
JRL noted that one of the tasks will be to migrate the Solaris Sybase DBs 
off the Suns and onto apm20.  There was some discussion regarding the VizieR 
UK mirror that we host, how it would be affected by this and how to resolve
this.

WFCAM: Is up-to-date. WFCAM is now back on the telescope and we expect the
first tranche of 06B data shortly.

UKIRT: Is up-to-date.


5.  Optical processing update

EGS said that the IPHAS release (r, i and H_alpha) will be made available to
the community via AstroGrid tools. He pointed out that only one piece of
software needs to be downloaded in order to use this. Initially 120 square
degrees are being released in order to test the system and receive comments.
Since there were no adverse comments so far and after some useful discussion
at ADASS, the whole survey is now being ingested.  There are still a few 
calibration issues that need sorting out.

It was noted that more IPHAS data is currently being taken.

EGS added that CMC14 was also being released via AstroGrid.


6.  WFCAM news

06B news: MJI and JRL reported on the latest news on WFCAM, which is now back 
on the telescope.  Tests are underway on the new baffling tube which should 
cut out remaining Moon glint problems.  New acquisition hardware has been 
installed and still has a few teething troubles.  The first batch of new 
tapes are expected in about a week.

It was noted that the photometric recalibration was needed for the DR2
release and was thus needed as soon as possible.  STH is working on this
(see earlier comments).

PSF fitting: DWE said that the remaining tasks with PSF fitting were to
implement a variable area cutout and optimize the background estimation. 
He was asked to email Phil Lucas in order to progress comparisons with 
other software packages. GPS and M17 fields would be suitable for this.    <<<<

It was noted that the data transfers are currently paused.  Related
to this MJI reported a conversation that he and RGM had with NCH about 
trying to further automate even the transfer initiation, which NCH agreed 
should be possible. PSB commented that over the last quarter, the IoA was 
the University department with the largest amount of network traffic.


7.  VISTA news

WJS reported on his week-long stay at Paranal and has written a concise
report. The general impression was good. The dome was almost light tight 
and the mechanics and electronics of the telescope seem OK. There were a 
few minor niggles about the mirror supports, but generally things were 
impressive. 

The mirror polishing remains on the critical path. 

The camera is in good shape and will probably ship from RAL by the end of 
the year, included in this is the requirement that the documentation
gets shipped at the same time.

Commissioning is expected in Autumn 2007. There was further discussion
regarding the CASU involvement in the commissioning; related to this
was the issue of purchasing and installing the summit pipeline computer 
hardware at Paranal. It was felt that this should be done soon. MJI 
noted that JPE was currently at ESO, meeting with Michele Peron and 
others on this and related topcis                         

MJI said that the ESO PSP is meeting shortly to decide which VISTA public 
surveys will go forward to the OPC.  After this set of hurdles a new 
management plan for the projects will have to be drawn up. This will be 
around December/January with a quite tight timescale and will involve
VDFS advice and feedback.

JRL reported on the VIRCAM AIT dark frames. There are many hot pixels, which
all have a "cross" shape.  Dark subtraction removes the transepts leaving
single hot pixels. These cannot be flat fielded out and some chips have
about 1% of these remaining hot pixels.  Some of these hot pixels are in
clusters but can all be flagged via the planned confidence maps.  He also 
noted that, unsurprisingly, to carry out the dark correction a dark with 
matching exposure time is needed otherwise the transepts are not removed.

Curtaining is present in VISTA data and at a similar level to WFCAM.
The pattern carries across channels and all 4 detectors on the same
controller, but not across the whole array of 16 detectors.  It is thus 
introduced at the controller level and can therefore be measured by taking 
a robust average across rows for all channels and the 4 detectors. 
This patterning will not be removed in the summit pipeline.  MJI said
that he would contact Mark Casali to see if this is a known "feature" of 
the ESO controllers.                                                       <<<<

There is a largeish dead patch on Detector 1 which does subtract out but 
remains dead, so don't put interesting objects there.

The dark current is quite high (ie. measureable) at 0.5 ADU/s/pixel. The 
read noise averages about 25 e- and the gain around 4 e-/ADU.

A worry flagged was that detector#14 has a misbehaving channel.

JRL will release a report on this soon.                                    <<<<


8.  AOB

MJI said that the registration deadline for the ESO Calibration Workshop to
be held at Garching in Jan 2007 is 6th November. PSB, MJI, MR and JRL are 
planning to attend.

The central heating in the APM building is finally working properly after
a mere 18 months of effort.

The warped windows have been bodged shut for the winter. Presumably they
will be bodged open again for the summer.

FvL wants to know as soon as possible who wants to work on aspects of the 
Gaia GDFS project.  This is needed for planning for the new recruitments 
which will be initiated in the New Year, assuming all goes to plan.
 
All were asked to think about this and then go and talk with FvL and MJI.  <<<<

NAW raised the issue of buying hardware to run the service distributing
IPHAS data. There was some discussion as to who pays for this and how
powerful a machine was required. It was decided that a machine similar to
the CASU web service provider would be ideal.  It can then be bought as a 
spare for running the CASU web services and also can be used for the IPHAS 
web service in the interim.   


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

JRL  finish the fix to problem with UKIRT archive (missing header information)

STH  generate poster of supernova remnant image received from Albert Zijlstra

STH  investigate effects of stacking on 2MASS/WFCAM non-linearity comparison

JRL  repair AAT archive mirroring (PostgreSQL problems)

MJI  email new WFCAM colour equations to DWE and JRL
STH

STH  agree new WFCAM colour equations with Calibration working group

RGM  report back on classification aspect of cross-talk weeding

JRL  add detection filter FWHM choice as command line option of pipeline 
     version of imcore.

DWE  update Plone technical pages on astrometry when astrometry gets updated
MJI


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

MJI  email Derek Ives about WFCAM intrapixel sensitivity measures

EGS  backup ING archive

DWE  remind Phil Lucas about the PSF fitting comparisons discussed previously

MJI  contact Mark Casali about curtaining in ESO controllers 

JRL  release report on VIRCAM AIT dark frames

ALL  think about Gaia involvement and discuss with MJI and FvL

EGS  organise purchase of new server as spare for CASU web services and for 
     running IPHAS web service