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24 September 2003
Present: MJI, JRL, PSB, DWE, JMI, STH
Agenda
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1. Actions from last meeting
2. Comments on WFAU minutes
3. Report from RAL camera design review meeting held 17-19th Sept
4. JRL's visit to JAC
5. Progress on deliverables for Quarterly report
6. AOB - filling in .away
document nos. and their wrangling
There are two reports filed for comments plus Pete's updated ESO docs,
discussed under item 5.
http://www.ast.cam.ac.uk/~wfcam/docs/reports/interleaving/
http://www.ast.cam.ac.uk/~wfcam/docs/reports/astrom/
http://www.ast.cam.ac.uk/~wfcam/internal/WP2/
Minutes
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1. Actions from last meeting
STH no progress with Sandy Legget's data, ongoing <<<<
JMI have updated and converted the pipeline milestones tasks and dates
MJI document to HTML (http://www.ast.cam.ac.uk/~wfcam/docs/milestones.html)
JRL and filled in most of the relevant entries.
MJI is awaiting AA's return from holiday (re. UKIDSS Survey Manager). It was
decided to transfer this to JRL who is about to visit JAC. <<<<
MJI it was decided to postpone updating Section 2. of DFS user requirements
document since it was not needed by the Camera Design Review.
STH still needs to write a context intro for simulation report <<<<
STH JRL will discuss the setting up of the photometric standards fields
within the characterization plan with Paul Hirst or Andy Adamson
during his visit to JAC. <<<<
DWE has emailed STH with his additions to the characterization plan. STH
will pass these on to JRL who will raise them during his JAC visit. <<<<
STH has not yet extended the number of fields that he has established for
WFCAM to the south for use by VISTA. It was decided that this should
be an early Q4 task with a timescale of 1 month. <<<<
DWE altered the documentation web page so that there are release and revised
dates next to each entry. The web page was still viewed as having too
much information on it and being hard to navigate. The filenames were
regarded as unnecessary. The document numbers also need to be added.
DWE and STH will sort this out. <<<<
DWE did equivalent 2x2 interleaving plots cf. 3x3 demonstration and placed
the results on web (part of interleaving report in
http://www.ast.cam.ac.uk/~wfcam/docs/reports/interleaving/)
DWE had a look at the 2MASS web pages for examples of "interleaving"
efficacy, but no suitable information was found.
DWE has written report on interleaving work (see above).
MJI provided feedback on VISTA IR detector test procedure document to
JRL Jim Emerson and Malcolm Stewart, and at the Camera Design Review
PSB meeting to the author.
PSB sorted out the accommodation, agenda and exact location for CDR meeting
at RAL.
DWE emailed Andy Batey to request a link to CASU from the research page of
the IoA web site. This alteration has not been done yet - monitoring <<<<
STH updated the prototype pipeline progress (WFS) scripts and web pages.
JMI
PSB has obtained the overview of the VISTA IR camera design. However, this
was in paper rather than electronic form. MJI will ask at the quarterly
meeting about electronic access to these documents. [However, Steven
Beard in a pre-emptive strike provided the relevant information -
see ~wfcam/public_html/internal/vista/ESO_starter.txt]
PSB have ordered a rack-mountable data server PC to go with the recently
MJI received LT02 tape drive/library unit. The LT02 is currently being
tested on cass38 and is being used to backup the CASU data disks.
The data ingest server PC will be a 3GHZ twin Xeon processor system
with 4x300 Gbyte IDE discs served through a 3-Ware controller. The
operating system will start off as RedHat Linux. Delivery is expected
next week, delay was caused by 2 week wait for enclosure.
2. Comments on WFAU minutes
It was unclear whether the disc problems encountered at ROE had any
parallels with CASU systems. MJI said that he would contact NCH to get
some more details. <<<<
The proposal for a central VDFS web site was noted.
There was some interest in the deliberations going on regarding what
distribution of Linux was best. There is a growing feeling that RedHat
has too many updates and releases to ergonomically maintain.
3. Report from RAL camera design review meeting held 17-19th Sept
PSB reported that the 3 day meeting, attended by 20-25 delegates, was very
interesting. While many of the presentations were very detailed, some were
still preliminary. In general though the CASU group were impressed.
PSB attended all 3 days, JRL and MJI for most of the final 2 days. The
latter two gave a presentation of the general plans for pipeline processing
VISTA (and WFCAM) data.
The camera control software presentation was given by Steven Beard. It was
unclear whether he was the only person working on the coding aspect of the
VISTA camera software interface. Some concern was expressed if this was the
case, due to the size of the task and the tight timelines.
An example of the usefulness of the meeting was the instigation of a
solution to monitor stepper motor errors via their reporting within the
FITS headers. And as a real bonus, CASU brought back some examples of
engineering data from a 2kx2k Raytheon detector already delivered to RAL
and were pleasantly surprised by the quality of the data. Many useful and
fruitful discussions regarding data capture and aquistion were had and
overall impressions of the IRAC controllers + Raytheon detectors were very
favourable.
There was some quite a lot of discussion regarding the Data Interface
Dictionary. CASU agreed to supply a draft version of this to RAL/ATC
within the next 2 weeks. <<<<
4. JRL's visit to JAC
JRL will be at the JAC from September 29th to October 5th inclusive. The
purpose of this visit is to progress a number of outstanding issues that
have proven impossible, or impractical, to do remotely. JRL and
JAC staff held a conference phone call last week to detail plans for the
visit. The main one being to install the CASU WFCAM DR pipeline on a JAC
machine and demonstrate the functionality of system up to the level of
milestone 4. A further aim will be to ensure that JAC staff are able to
check the CASU system out from the CVS, build it, and exercise it with
UFTI data.
There was also some discussion on the ORAC-DR infrastructure the CASU
WFCAM DR pipeline is using. JRL confirmed that WFCAM ORAC-DR uses the
ORAC_ generic FITS headers and agreed to look into moving the MEFITS
header reader code into the Astro::FITS::Header module rather than keep
this generic code in ORAC-DR. Since this was an unexepected imposition,
JRL asked JMI to help out with this task and will take the modified code
with him.
Further discussions with JAC staff will be continued at ADASS, where JRL,
FE and TJ will all be present.
JRL will also sort out various UKIRT Archive and OMP database issues
regarding updating WFCAM FITS headers in Cambridge with observer comments
and other ancilliary information; and discuss aquiring Sybase replication
licences at both ends for automating DB mirroring.
It was thought that this visit would also be the best opportunity to discuss
several other issues raised in earlier action items.
5. Progress on deliverables for Quarterly report
MJI briefly described his astrometric distortion report. It was noted that
for WFCAM the spatial distortion would be significantly wavelength dependent.
It was note that an "r-cubed" radial distortion model gives a very good fit
to the ray-traced distortion pattern and that further work on characterising
the distortion can only be done using real on-sky data.
One of the many conclusions from the report is that there is approximately
a 10" diameter limit to dithering patterns for WFCAM before non-linear
resampling at the detector level is required. For VISTA, no practically
useful dither is possible without non-linear resampling. It was also
noted that the scale distortion has an impact on photometric measurements.
For WFCAM the size of the effect varies from 0% to 1.6% ie. comfortably
within a +/-1% overall systematic calibration error budget. However, for
VISTA the size of the effect varies from 0% to 3.5% and without correction
would overflow the entire systematic photometry error budget.
Both "problems" for VISTA will require a more sophisticated version of the
pipeline to deal with them. This has already been planned for and will be
incorporated as an option in Version 3. of the WFCAM pipeline (ie. Version 1.
of the VISTA pipeline).
A few minor changes for clarification of some points were requested and
these will be incorporated prior to release on the documentation web
page. <<<<
DWE described his interleaving report. In addition to what was reported
last time some 3x3 interleaving tests have been carried out. These show
an improvement at the bright end over 2x2 interleaving, however it is
anticipated that in real data additional effects will be present that will
also limit the bright end positional accuracy. MJI suggested that the
profile fitting software written for DIVA tests could form the basis for
PSF fitting tests on this data. However, he was of the opinion that
straightforward profile fitting of hedgehog-like PSFs on interleaved data
would not work very well and that in the end simultaneous PSF fitting to
each individual component frame may well be the best solution.
The slightly revised version will be put on the public web pages. <<<<
There was also some discussion regarding why interleaving currently
affects the detection limit.
When real data is available it will be worth comparing results obtained
from simply stacking all the frames, compared to processing them as
interleaved frames. Interestingly, the hedgehog-like frames are not
visually appealing either ("look like shite" was one comment).
It is a moot point whether interleaving real data is worthwhile - we
will see.
The deliverables from Q3 were then discussed in detail. As usual we all
need to send in a summary for the Q3 report and suggestions for new
deliverables for Q4 to STH and MJI by Thursday evening. <<<<
6. AOB
Filling in .away: we were all encouraged (again) to fill in our .away
files regularly and preferably in advance.
Each document we have produced has to be allocated a document number.
STH will write a document describing the document numbering scheme and
keep track of the numbers. <<<<
Amazingly, we have received our contract renewal letters. Except PSB,
but he's already got one anyway.
Continuing Actions
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STH check Sandy Legget's data and (probably) send in a request for more
data.
STH write context intro for simulation report
STH extend the number of fields that he has established for WFCAM to the
south for use by VISTA. It was decided that this should be a Q4 task
with a timescale of 1 month.
DWE will monitor the visibility progress of CASU on IoA web pages
New Actions
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JRL during JAC visit, find out from AA about the UKIDSS Survey Manager
appointment on Hawaii.
JRL discuss the setting up of the photometric standards fields within the
characterization plan with Paul Hirst and Andy Adamson during visit
to JAC.
STH pass on DWE's additions to the characterization plan to JRL who will
JRL raise them during his JAC visit.
DWE remove the filenames from the documentation web page and add the
STH document numbers and reformat to be more user friendly
MJI contact NCH for more details on the ROE disc problems and plans
for alternative Linux systems.
PSB write real draft version of Data Interface Dictionary document and
MJI supply to RAL within 2 weeks.
JRL
JRL get as far as Milestone 4 by the end of JAC trip.
JRL pass on CASU additions to the characterization plan.
MJI make minor changes to astrometric distortion report and place on web
DWE place interleaving report on public access side of web
ALL send in a summary for our Q3 report and new deliverables for Q4 to STH
and MJI by Thursday evening.
STH provide a document number for each released CASU document and write
a document describing the scheme. Also keep track of these numbers.
