[fitsbits] WCS Papers I, II, III version release

[Eric Greisen]

Greetings,

New drafts of the three World Coordinate System papers dated 2002/04/23
are now available from

   http://www.aoc.nrao.edu/~egreisen/

and

   http://www.atnf.csiro.au/~mcalabre/

As previously, the new drafts of Papers I & II are colour-coded to
highlight changes made since the last public release on 2001/12/12.  This
colour-coding is done manually and does not include spelling, grammatical,
or typographical changes or changes of an inconsequential nature.  An
overview of the main changes is given below.

Papers I and II have had substantial community review and feedback and
we consider them to be very close to "final form".  They represent what
we believe is a consensus on formalism and presentation.  It is our
intention to submit them for publication in A&A on 2002/07/01, thus
further community input is required within the next few weeks.

Paper III has advanced substantially in the past few months, so much so
that the changes are not colourized; interested parties should reread it
in toto.  The 2002/04/23 draft is presented as a snapshot of current
development and is aimed particularly at prompting community feedback.
There will be plenty of time for review and further development; we will
allow at least 6 months, possibly up to 12 months if there is vigorous
feedback.

Paper IV is in development and community input will be requested soon.

The text of a proposal by Steve Allen and Doug Mink for "Concatenation of
FITS World Coordinate Systems" is also now available for general review.
This was raised on the fitswcs mailing list on 2002/01/01 and following  
and ideally would have been included in Paper I.  However, we felt that
the FITS community had not had adequate time to review it, yet we didn't
want to delay Paper I further.  Thus it is presented as a separate
proposal; see
      http://www.ucolick.org/~sla/fits/

Overview of the main changes to Paper I & II:

   1) The formalism of the linear transformation has been recast to place
      equal emphasis on the use of the PC and CD matrices.  The use of
      mathematical matrix notation in Eq. (1) then led to interchanging
      the "i" and "j" indices on the keywords and changing the alternate
      axis descriptor suffix from "s" to "a".

   2) A header construction example has been added to Paper I.

   3) The tables summarizing new keywords have been revamped.

   4) Header construction example 3 of Paper II has been augmented with
      a detailed discussion of representations using the CD and PC
      matrices.

   5) The text has been carefully proofed by Bob Hanisch & Steve Allen.

Comments on the papers may be directed to the fitswcs mailing list -
fitswcs at nrao.edu.  See
     http://listmgr.cv.nrao.edu/mailman/listinfo/fitswcs. 
for more information.


Mark Calabretta, ATNF
Eric Greisen, NRAO
Frank Valdes, NOAO
Bob Hanisch, STScI
Steve Allen, UCO/Lick