[fitsbits] Re: [fitswcs] WCSLIB 3.3

[Doug Mink]

Stephen Walton wrote:
> 
> On Thu, 2003-10-23 at 08:48, Doug Mink wrote:
> 
> > My WCSTools package supports all of Mark's projections (though I am still
> > in the process of upgrading it from WCSLIB 2.9 to WCSLIB 3.3) and reads
> > IRAF imh files as well as FITS files.
> 
> Thanks for taking the time to answer, Doug.  I do have one question:
> when you say WCSTools "reads IRAF imh files" does that mean it works
> with both the PC and CD matrix formalisms?

WCSTools supports both PCi_j and CDi_j matrix formalisms, as well as the
PC00i00j keywords which were in some of the early drafts of the FITS WCS
papers.  The order of preference, if for some reason multiple formalisms
are present is CDi_j, PC00i00j, PCi_j, and finally CDELTi/CROTAi.  If
CTYPEi is not present, DSS keywords are checked; if they are not present,
a non-rotated north-up, east-left TAN projection centered at RA,DEC at the
center of the image, with a scale in arcseconds per pixel specified by any
of several commonly used variations on SECPIX is initialized.

WCSTools can read IRAF imh files created on any computer (IRAF characters
in headers in old imh files are two byes and hence endian like the data in
either of the two imh formats.

-Doug Mink
 Telescope Data Center
 Smithsonian Astrophysical Observatory
 Cambridge, Massachusetts USA