[fitsbits] Proposed Changes to the FITS Standard

[Thierry Forveille]

Maren Purves a écrit :
> - do we still have
> FITS files without extensions?
> 
Yes we do :-) For instruments that naturally generate measurements
on a regular 2D grid (such as simple optical/IR imagers with a
single CCD/IR sensor) the pre-extensions standard works perfectly
and they typicall use it. Several (mostly older) CFHT instruments
do that, and I expect most optical observatories to be in a
similar situation. If extensions ever were made compulsory those
instruments could of course put their data in an IMAGE extension,
but there is little point in doing that.

> It being "once FITS always FITS" I object to making the
> EXTEND keyword optional.
> 
I don't particularly object to the EXTEND change (which doesn't
invalidate any old FITS file, just gives a (very) small added
flexibility to new ones, so doesn't break the "once FITS always
FITS rule"), but don't see its point either. Of course it saves
80 bytes in every FITS file, but I suppose there must be some
stronger reason :-)