File contents

29th April 2008  APM comfy chairs  11:30-12:40

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

Agenda
------

1.  Actions from last meeting
2.  Comments on WFAU minutes
3.  Recent meetings/visits   - VMC meeting in Herts
                             - upcoming Video meeting
                             - NAM
4.  Data archives update     - AAT, ING, WFCAM, UKIRT
5.  Other processing update  - VST news
                             - IDR IPHAS paper
                             - HawkI
6.  WFCAM update             - illum corrs tests/checks
                             - photometric calibration paper
                             - ftp transfers
                             - flippin' jitters
                             - processing status 08A
                             - upcoming UKIRT board meeting
7.  VISTA update             - general news
                             - new SADT release
                             - pipeline progress
                             - data connections to ESO; ftp tests
8.  ADASS 2007               - done ?
9.  AOB


Minutes
-------

1.  Actions from last meeting

MANY have provided comments on the latest draft of the photometric 
     calibration paper.  STH said that comments from DWE, NCH and 
     Paul Hewett had been incorporated. Two more items need to be dealt with 
     and the paper will then be submitted.
     
JRL  has finished off checking why the pipeline catalogue software and 
     toolkit give different results in a few specific cases. They now agree 
     to within rounding errors.
     
STH  has not finished checking if the information on the Plone astrometry 
     technical pages is up to date - ongoing                               <<<<

MJI  is still waiting for the transmission curves for VIRCAM Z and N118 
     filters from JPE - ongoing                                            <<<<

MJI  has found out what SDSS do about elliptical apertures for galaxy
     photometry.  The short answer is that the standard pipeline analysis 
     eg. Petrosian magnitudes, is based on circular apertures.  The slightly
     longer answer is that from DR5 an alternative method is used (and
     recommended), known as Cmodel magnitudes.  These are model fitted 
     fluxes based on a linear combination of exponential and de Vaucouleurs 
     model fits.  Each component is elliptical.  This is similar to the
     planned future upgrade for elliptical model fits based on Sersic
     profiles.
     
MJI  still needs a final check that the SMPs are up-to-date - ongoing      <<<<
RGM

JRL  has not revived the changes log web page for WFCAM pipeline - ongoing <<<<
     
JRL  has held lengthy and detailed email discussions with JAC staff about
     enabling the pipeline to cope with offset sky strategies

STH  has not yet looked at the new SADT - ongoing                          <<<<

MJI  has acquired a copy of the latest VISTA integration schedule but has 
     not yet got his mitts on the commissioning plans - ongoing            <<<<

JRL  has negotiated and fixed a date for the CASU barbeque - see later


2.  Comments on WFAU minutes

MJI noted from recent WFAU minutes that WFAU thought our commenting on the 
IAC request for access to all the WFCAM processed image data was an April 
fool.  Sadly: a.) we didn't think of it and b.) the request was genuine.
We have not heard any further on this topic but await Eduardo's return
from La Palma with interest.

MJI also suggested that STH get in touch with NJC and ETWS about the tests 
he carried out using the LAS to confirm the efficacy of the illumination 
correction.  MJI independently confirmed the detector level improvement a
while back using his U/05B/7 data on M33.                                  <<<< 

There was a brief discussion about the radial photometric distortion
correction and whether or not it had already been applied in DR3. RGM
supplied a graphic showing the size of the affect for different
passbands and asked if it, or something similar, could be included in
the Plone technical pages.                                                 <<<<


3.  Recent meetings/visits

Not a lot is happening on the external meetings front.  MJI noted that he
had attended the VMC planning meeting at U. of Herts. on 8th April and
gave the usual CASU VDFS spiel.  RSC was also there and did the same for
WFAU.  A fair bit of science was discussed but no new surprises about 
processing came up.

MJI noted there was an upcoming Video survey team meeting end of May/early
June but no date or venue was available yet.  He wondered if VHS, Viking
and VVV were going to do the same at some point, but all had been quiet in
the Hobyar House.

He also asked if anything significant, other than the zero-cost model for
ground-based survey astronomy, had been aired at NAM - apparently not.

MJI pointed out the upcoming Euro-VO Workshop on how to publish data to the 
Virtual Observatory, 23-27 June 2008 at ESO, Garching.  The registration 
deadline is 14th May 2008 (http://www.euro-vo.org/dcaworkshop2008/index.html)


4.  Data archives update    

AAT:
JRL commented that we had recently received more AAT data which had been
ingested into the archive, which was now up to date.  He also reported that 
we have "A satisfied customer. We ought to have him stuffed." - Basil

ING:
The raw archive is up to date to end of March.  April data is awaiting the
30th to arrive before it too gets the ingestion treatment.

UKIRT:
JRL said the Cass archive was up to date in terms of available data and
that he was awaiting the next batch.

WFCAM:
MR reported that the raw archive was tracking the newly arrived WFCAM
data a few days in arrears due to the various checks, MEFing and fixes 
(see later) that occur before ingest.  Tape backups of 08A raw WFCAM MEF'd
and checked data are tracking about a week behind that.


5.  Other processing update  

VST news:
MJI relayed the following snippet, "I hear consistent reports that the VST 
should be operational starting from 2009 (the M1 cell should be sent to 
Paranal end 2008)".  VISTA is still the front runner but watch this space.

IDR IPHAS paper:
This has carefully negotiated its way through the refereeing process and is
now "in press".

HawkI:
RGM reported on a comparison of manually driven IRAF-based reduction of
science verification data from HawkI with the same data processed by JRL 
using a variant of the CASU NIR pipeline.  The CASU version goes 0.2 mag 
deeper.


6.  WFCAM update           

Data transfers:
FTP'ing of raw WFCAM data from JAC continues to work seamlessly with data 
typically arriving here within 24 hours of it being taken.

A new, but fortunately minor, problem related to scaling of coadded exposures
was noticed whilst processing the first few nights of 08A data.  The cause
of this was traced to the FITS compression conversion due to a software 
upgrade of the external cfitsio library, which we had supplied prior to 08A 
data taking.  A patch has been issued to JAC to fix it. Already transferred 
data is fixed here in situ prior to ingestion to the raw WFCAM archive and
subsequent transmission (UKIDSS and CAL data) to ESO, and of course pipeline
processing.

Processing status:
In spite of the scaling problem and a few others relating to missing darks 
and missing RECIPE keywords, processing is rapidly catching up with data
taking, though final checks and monthly zero-point updates remain to be 
done. As usual the status pages for 08A show the current state of play 
http://casu.ast.cam.ac.uk/surveys-projects/wfcam/data-processing/
and derived quality control diagnostics.  All of Febuary 08A is now checked
and flagged as read to copy to Edinburgh.

Some requests for urgent early access to various bits of processed 
service or PI data for 08A have been received (20080401 Patel U/07B/18; 
20080331 Tedds U/SERV/1779; 20080331 McMahon U/SERV/1783; 20080310,20080320
Haines U/08A/32) and were dealt with by directly transferring processed 
data to the PIs.

JRL expounded briefly on the discussions relating to automating offset sky
data taking, and subsequent pipeline processing, for observations involving
large extended objects.  In a nutshell two modus operandi have emerged:
flipping large extended objects between pairs of detectors either as 
1,4 <-> 2,3 and 1,2 <-> 3,4; or for bigger objects genuine offset sky
alternating with on target exposures.  The former is a cunning plan as it 
provides an efficient way to be always integrating on both target and sky, 
simultaneously even. 

Photometric calibration paper:
The status of this is as noted earlier.  The remaining "todos" are confirming
the overall spatial coherence and accuracy of the absolute calibration.

Other:                           
MJI noted that there was an upcoming UKIRT board meeting in Oxford, 
May 15-16.  A copy of the submitted (to JAC) CASU and WFAU reports was
circulated with the draft agenda (of this CASU meeting). He also commented
that he had not seen any UKIDSS report yet.

MR reported that he had been contacted by Tiziano Valentinuzzi from Padova 
about stacking and mosaicing some U/05A/2 project data on Abell Clusters.
A preliminary comparison somewhat surprisingly revealed that the CASU
stacked and mosaic'd image using the CASU toolkit software on a trial
cluster (starting from the normal pipeline science products) gave results 
that went 0.75 mag deeper than the SWARP'd MONTAGE'd image created using 
the same data in Padova.  

MJI also noted that he had seen a bunch of recent emails relating to putting 
the UofH proposed 50% share of time for joining the UKIDSS consortium back 
on the negotiating table again.


7.  VISTA update   

We all noted the encouraging news about safe mirror delivery to Paranal
and the subsequent press releases.  The phrase "Full scientific operations
are due to start early next year" caught the eye.

ESO have released CPL 4.1.0 which incorporates JRL's CPL interfaces
to WCSLIB. Ironically this will now require a compatible release of
the VIRCAM Data Reduction Library, which incorporates a private version
of the interface, which should be announced soon.

We are still waiting to receive the digital versions of the Z and N118
filters and likewise feedback on the current Calibration Plan draft.

A repeated request for the "CASU wishlist" for VIRCAM data was responded to
with a repeated reply. It seems unlikely that any more lab data will be
produced much before camera first light.  Some further analysis of the
July 2007 data is being undertaken, however the high-order effects that need
investigating are really too correlated in the existing data and there is
a danger of over-interpretion.

Networking tests to ESO are underway sporadically. Florian Heissenhuber,
"Network Specialist" has been working with PSB.  Simple ftp's seem to
achieve ~5MByte/s which is easily fast enough for the transfer of raw
VISTA data from Garching to Cambridge (an average 250Gbyte night should 
Rice-compress to ~60Gbyte which at 5Mbyte/s would take about 3.5 hours to
transfer).  The preliminary conclusion is that the marginally adequate 
transfer speed of raw UKIDSS WFCAM data is, as previously suspected, due to 
the rate-limiting bottleneck of the ESO database ingestion process 
- that would not be a problem for transferring VISTA data to Cambridge. 
Further tests are stalled pending ESO IT support installing the "iperf" tool.

The RECIPE keyword and allowed values have been in the news recently.
These are still very much a work in progress and final agreement on them
will probably not be possible until after on-sky science verification 
has been completed.


8.  ADASS 2007 

The proceeding are outta the door.


9.  AOB

Infrastructure:
A 3COM 5500G network switch has been installed in the APM building as
part of the IoA's upgrade to 10Gigabit backbone and the University's
upgrade of the phone system to VOIP; the switchover of machines will
happen later (there may well be a glitch in the UKLight VLAN at that
time (and the APM WIFI!)).

CACC:
There will be a meeting of this august body on Thursday.  MJI and PSB will 
attempt to find out what the current University network usage costing
model is in light of all the lovely FTP'd incoming data.                   <<<<

Meeting area:
The partition isolating the computer rack noise was completed on Friday hence
it is time to consider setting up a group meeting area.  MJI will 
investigate meeting table options and DWE will liaise with Andy Batey      <<<<
about wall-mounted display screen options.                                 <<<<

The new fridge-like quality of the main room area (not surprising given
the location of the sensor) is already being taken care of.

BBQ:
There was a brief discussion about arrangements and preferences for the CASU
summer? BBQ, but as you don't need to know about that .....................


Continuing actions
------------------

STH  check that Plone astrometry technical pages are correct

MJI  acquire transmission curves for VIRCAM Z and N118 filters

MJI  finish off checking and acquiring the latest SMPs
RGM

JRL  revive changes log web page for WFCAM pipeline

STH  download, install and try out new SADT

New actions
-----------

STH  contact NJC,ETWS about details of LAS tests on illumination correction

STH  include graphic showing the size of the photometric radial distortion
     correction in the Plone technical pages.                              

MJI  find out at CACC meeting what the network costing model currently is

MJI  investigate meeting table options for the APM building

DWE  liaise with Andy Batey about an APM wall display screen