From psb@ast.cam.ac.uk Mon Jun 30 11:09:40 2003
Date: Fri, 27 Jun 2003 12:16:47 +0100 (BST)
From: Peter Bunclark <psb@ast.cam.ac.uk>
To: Jim Emerson <j.p.emerson@qmul.ac.uk>, Mike Irwin <mike@ast.cam.ac.uk>,
     Jim Lewis <jrl@ast.cam.ac.uk>, William Sutherland <wjs@ast.cam.ac.uk>
Cc: Simon Hodgkin <sth@ast.cam.ac.uk>, Dafydd Wyn Evans <dwe@ast.cam.ac.uk>
Subject: VDFS meeting at IoA Wed 25 Jun 2003

VDFS Planning Meeting 2003-06-25 at IoA

Present: JPE Jim Emerson
         JRL Jim Lewis
         MJI Mike Irwin
         PSB Peter Bunclark
         WJS William Sutherland

1. WFCAM/VISTA FITS compatibility.  General discussion on the ways in
   which WFCAM data may be ingested into the ESO archive.  Positive suggestions
   include translation using ESO's Fits Translation Utility (FTU), and
   that WFCAM headers should be checked for potential truncation when
   right-shifted.
	Action JPE to draft response to Peter Quinn explaining the situation.

2. VDFS User Requirements.
   Discussed lack of up to date applicable documents; most urgently
   Observing Protocols which will define total set of observation types
   that VDFS will be required to process, and also the VISTA scientific
   case which is out of data and heavily biased towards the Visual Camera.
   Many of the VDFS user requirements, particularly precision limits, stem
   directly from the Science Requirements and need rethinking.
	Action on WJS (and Gavin Dalton) to produce draft Observing Protocols
        by end 2003-07

   Various items lacking in VDFS UR identified;  need whole new section
   on Quality Control at Paranal (QC0 & QC1),  reference section,
   change-control section.  Base on existing WFCAM DQC measures.
	Action on JPE to add extensive comments to existing document,
        pass back to PSB for further enhancement.
        Action JRL expand calibration requirements section.

   Discussion on setting finite limit on VDFS deliverables; consensus
   that pipeline stops having produced a calibrated `Paw Print' and
   further image combination and processing is a feature of individual
   research projects.

   Discussed technical aspects of dithering, need to know optical
   distortion coefficients.
	Action WJS to dig out optical characteristics, pass to MJI.

   Question raised, can camera/telescope/autoguider be used to step
   precise small distances, in particular integral pixel distance?
   Discussed IRACE controllers for IR, SDSU for wavefront, autoguider.
   Need to know data output R*4 or I*4 ?
	Action WJS  ** see addendum

   `Public' VDFS UR needed by Camera Software Status Review 2003-09-19.

3. Camera Lab-Calibrations
   Discussed calibration plan, re-iterated wish for a spot-projector
   to test persistence, crosstalk, a means of testing for non-linearity.

4. Data Interface Dictionary.
   PSB has discussed with Steven Beard the state of the DID.  Steven
   has included a good start as a temporary appendix to the
   IR Camera Software Functional Specification.  PSB asserts that the
   DID is needed while writing VDFS UR;  JPE raised conflict between
   lack of DID and Camera FDR.  Consensus is that editorship of DID should
   be a VDFS task with contributions from the telescope and instrument teams.
	Action PSB produce draft DID as 2003-Q3 deliverable.

** WJS action, response from  Nagaraja Bezawada:
1. The data is 32 bits. Unprocessed data (e.g. Single CDS frame) is
stored in 32 bit signed integers. Processed frames (e.g. Average of 10
CDS frames) are stored in real (32 bit) floating point numbers.
2. The co-adds or averaging are all done in the number crunching work
stations.
3. I haven't seen any option of non-linearity correction to the data.
But, I will check with ESO and let you know.