Hi Mark -

You are right, flame-bait was probably too strong a term (it
had been
a long day).  I don't think there is any point in us getting
into a
long discussion of the history of WCS; I was merely
objecting to your
suggestion that IRAF merely adopted WCS after it had been
developed,
implemented, and proven in AIPS.  That was too much to let
pass
without a comment.  But I don't want to let this distract us
from
the very important polarization discussions.

> Original versions of G&C (it started as a single
paper) used the CDi_j
> variant of the CD00i00j matrix proposed by Hanisch
& Wells (1988) which
> came from the NASA-sponsored meeting held in
Charlotesville in Jan/1988.
> Isn't that where IRAF got the CD matrix?

Indeed this is where the CD matrix came from - it grew out
of work
done primarily by the STSDAS group at STScI.  Bob and the
STSDAS
group at the time were members of the overall IRAF project,
of course.
The CDi_j notation is what is used in IRAF MWCS (see below),
although
I don't remember anymore exactly how we came up with this
notation.

> > - the current WCS implementation
> >in IRAF predates the WCS standard.
> 
> Doesn't it use WCSLIB?  Lindsay provided me with much
valuable feedback
> on the earlier versions of WCSLIB.  I was given to
understand that she
> was modifying IRAF to use it.  (Sadly, AIPS, Miriad and
karma also have
> not progressed beyond the AIPS convention and I'm sure
there are many
> more.)

No, IRAF does not use WCSLIB, that came along much later. 
The IRAF
implementation of WCS is MWCS, which was introduced in
1989.
Many modern WCS concepts were introduced in MWCS, although
they may
well have been developed independently in AIPS at about the
same time.

Cheers,

	- Doug

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