Sub-group on the Densification of the Optical Frame
                             Newsletter 7
                             July 25, 2000


Dear Colleagues,
  This is the seventh newsletter of the Sub-group on the Densification
of the Optical Reference Frame.

There are a few items I would like to share before the IAU General
Assembly.

1) The website has changed slightly.  The new address for the homepage is 
   'http://ad.usno.navy.mil/dens_wg/dens.html'.

2) The informal gathering of those working on astrometric surveys has had a 
   change of times.  It is now set for Session 3 (14.00-15.30)
   in room Roscoe 3.5 on Monday, August 14.  Please note that this
   is NOT a meeting of our sub-group, but the topics will interest
   many of us.  This is being organized by Dafydd Wyn Evans
   (dwe@ast.cam.ac.uk).

3) Elizabeth Griffin has asked me to distribute the following message:

   From Elizabeth Griffin --
   On Monday August 14, 1400-1730, the diary shows a Joint Commission Meeting
   for the WG for Spectroscopic Data Archives. The purpose of our meeting is
   to discuss current projects to "rescue" the information on photographic
   plates by fairly large-scale scanning.  There are at least two
   international projects on the drawing-board: one to scan direct plates
   from European observatories, to be set up at Brussels Royal Observatory
   (see http://midasf.oma.be/~fido/ovid.html),
   and one to scan world spectra, hopefully to be set up in Canada (see
   http://herbie.ucolilck.org/techdocs/vo/).

   We would like to invite anyone interested to participate in that meeting,
   in particular those whose home institutions have stores of plates -
   whether or not the plates are in current use.  One objective is to gather
   statistics about the plates, their anticipated usage, and about any
   associated equipment.  The projects mentioned above require shipping the
   plates to a central location for scanning; another objective is therefore
   to discover whether permission to borrow an entire plate store, either on
   a short-term or a long-term basis, is likely to be granted.  We are also
   interested in any local efforts (e.g. by casual labour) to generate
   on-line catalogues of the contents of plate stores.

   The meeting will not be structured as a formal papers session, but will
   be handled as an open discussion under a series of topics:

   * The need for rescue missions
   * Information on:
     - the WG's own project for world spectra
     - UDAPAC in Brussels, for direct plates in Europe
   * How all observatories can participate
   * Basic information required:
     - sizes and conditions of plate-stores
     - any auxilliary equipment no longer wanted
     - will observatories support these projects by lending/donating plates?
   * Generating a world resource
   * Sources of funding

   Given that the IAU is already nominally supporting these rescue missions,
   the purpose of the meeting is to kindle a discussion among owners or
   managers of plate stores.  Contributions of facts and figures that are
   being offered on the spot should preferably be presented as view-graphs.

   For further information, please contact Elizabeth Griffin
   (remg@astro.ox.ac.uk).



                  Sincerely,
                                       
                  Sean Urban
                  U.S. Naval Observatory, Washington D.C.
                  July 25, 2000
                  http://ad.usno.navy.mil/dens_wg/dens.html