Subject: Charter for postage_stamp mailing list

From: [email-masked] (Doug Mink)
Date: Wed, 5 Oct 94 11:57:11 EDT

Astronomical Data Postage Stamp Image Mailing List

Welcome to the POSTAGE_STAMP mailing list.  It originated at the 1994
ADASS meeting as a means for discussing standards and procedures for
serving and viewing "postage stamp" images of an arbitrary portion of
the sky.  We want the mailing list to include everyone who has a large
public image database.  We expect to discuss standards for access, such as
keywords and coordinate systems, and standards for provided products, such
as compression and dealing with image overlaps and gaps.  To avoid unnecessary
duplication, work in progress as well as existing products should be discussed.

GOALS
Our first goal is to produce servers and client browsers to deal with simple
single-wavelength images including World Coordinate System (WCS) sky position
information.  We also need client software which can be executed from
within application programs, in order to compare survey catalogs, overlay
information, or facilitate astrometric calibration of optical imagery.
A major issue to discuss is the standardization of a compression method
(or methods--that is an additional debate).  Other tasks include finding
ways to deliver multiple simultaneous wavelengths and overlays of
catalogued data.  It is hoped that any software which is produced be
shared with the rest of the community.  Incremental goals will be set,
so that the large databases can be used as soon as possible.

WHAT EXISTS NOW
IPAC's 'ISSA Postage Stamp Service' currently serves 80x80-pixel WCS FITS
images with a selected center from the IRAS Sky Survey Atlas at URL
	http://brando.ipac.caltech.edu:8888/ISSA-PS
A more versatile Mosaic-based, multi-wavelength image server has been
implemented by the NASA/Goddard SkyView program at URL
	http://skyview.gsfc.nasa.gov/skyview.html
It also returns a FITS file with WCS information.

There is no viewer which automatically displays FITS files with WCS.
SAOimage can be used to display the images returned by SkyView, but it
does not yet deal with WCS information.  IPAC's Skyview (no capital V)
program can deal with WCS, but needs a better browsing interface.
The SAO Skymap program, described at URL
	http://tdc-www.harvard.edu/software/skymap.html
has extensive overlay capabilities, but only a rudimentary image display.

-Doug Mink ([email-masked])
 Telescope Data Center
 Smithsonian Astrophysical Observatory
 Cambridge, Massachusetts USA