[fitswcs] Quad Cube projections

[Doug Mink]

I recently have had inquiries concerning the CSC, or COBE quad cube,
projection, one of those in Greisen and Calabretta and thus supported
by Mark Calabretta's WCSLIB package.  I looked through the online COBE
archive and found that, while they use the projection, there wasn't
any data in the form of images.  I am wondering if anyone on this
list has ever seen an example of an image in the CSC (or QSC or TSC,
for that matter) projections.  Based on the changes I had to make in
the WCSLIB code to get it to work on a test CSC image, I would guess
that the code in cscfwd(), and probably cscrev(), was never tested
on a real image.  One problem with these projections is that they
number the six faces of the cube in a very non-FITS 0-5 instead of
1-6.  I modified the WCSLIB code to use 1-6 and am wondering how
people feel that this anomalous numbering system should be treated
in the FITS WCS standard.

-Doug Mink