Minutes of SHARE Meeting					11/28/01



1. Present: Tony Keyes, Dorothy Fraquelli, Mark Dickinson, Gerhard Meurer,
   Anton Koekemoer, Daryl Swade, Bill Sparks, Mauro Giavalisco, Jerry Kriss.

2. Thanks to everyone for the circulated drafts of current studies of
   implementation plans, resources, etc. Please see the standard format
   (Attached at the end of the minutes) for these based on what I've seen in the
   first drafts. Please tidy up within your small group of interest, then
   circulate to the whole SHARE group by 12/10/01 (week from Monday).

	*** We'll meet to discuss again in two weeks, on Dec. 12. ***

3. There was a discussion of whether WCS improvements are a prerequisite for
   image combination.  Bill says yes (or, at least it is a great help); Megan
   (hearsay) says no, and that image combination should be robust to WCS
   inaccuracies. Consensus seems to be that good WCS helps a lot, but is not
   absolutely required.

4. Note that new FITS standards (to be approved) have additional header keywords
   that do geometric correction of instrument (x,y) frame before application of
   CD matrix to obtain the WCS.

5. Anton summarized reaction of STUC to his status report last month:

	* They agreed with our rough ordering, at least for top 3 or 4 and
	  bottom 3 or so.

	* Strongest reaction was to the photo-z.  Thought that was better left
	  to individual scientists.

	* STScI should concentrate on those topics where it can make a real
	  difference that everyone appreciates.

	* There was some confusion over the difference between utilitarian
	  ("engineering") catalogs and science-grade catalogs until Anton
	  explained the differences. (We should do a good job of making this
	  clear in our final report.)
	  There was some sentiment also that STScI shouldn't make science-grade
	  catalogs, but this wasn't as strong as the negative reaction to the
	  photo-z.

6. Long discussion of philosophy of OTFR and some proposed tasks.  OTFR takes
   the approach that no products are saved. Everything is re-created from
   scratch each time.  Assumption is that reprocessing time and effort saved by
   storing results is less important than the gain from using current best
   calibration files and algorithms.  However, it would be nice to save catalogs
   long term, even engineering grade ones--- enables more sophisticated
   searches, and eases effort needed to align images for image combination.
   And then there is the issue of deriving globally useful information such as
   WCS corrections for some area of sky, or for some guide stars from some
   process (e.g., an image combination).  How would one save and then re-use
   this information later?

   This topic deserves more discussion.

7. Generating a "master catalog" based, for example, on all HST observations,
   goes beyond OTFR.  Could be an institute-level goal.

8. Status of the effort on the various topics:

	WCS	- Anton - substantial implementation plan; needs work on
			  resources and timescales.
	ImgComb - Bill	- draft implementation plan circulating
	Identification	\ Gerhard, Mark, Harry F. have discussed options and
	Catalogs	/ researched possible tools.
	Photo-z - Mark	- has a long, dismissive draft circulating
	Combining spectra - Tony - initial discussions w/ Howard. Feel that
				   existing tools can do this job.
	Time history - Dorothy - needs more work
	Spectral cubes - Jerry - needs more work
	Customized processing - Daryl - He and Howard have discussed
					possibilities and circulated a writeup
	Using SDSS - Megan - fairly detailed draft circulated

NEXT MEETING: Wednesday, December 12.  Stay tuned for time & place.

===============================================================================

Suggested format for new writeups that describe an implementation plan,
the required resources, and timescales for implemetnation.  Please add
these sections directly after the current writeups on each implementation
option.

Assumptions

	Describe aspects of the system that might not be obvious (or might not
	yet exist) that you feel are necessary to proceed with the
	implementation discussed below.  An example might be that
	image combination assumes that the WCS in the image header has been
	fixed to some accuracy.

Required Decisions

Min and Max Goals

	Most of our suggestions have a wide range of possible implementation.
	Set some min and max goals.  For example, for spectral combination,
	the min goal is to be able to combine spectra that were intended to be
	combined from the start (e.g., a dithered observation set).
	The max goal might be to combine all available spectra for a given
	location/target on the sky.

Implementation Plan

Required Resources 

	- For Min Goals

	- For Max Goals

Time Scales (for min and max goals)

	- For Min Goals

	- For Max Goals