[fitswcs] Improving FITS header astrometric information

[William Pence]

Doug Mink wrote:

> Of course I use the EPOCH keyword for the equinox and system
> if EQUINOX and RADECSYS are not present, but I am interested in
> suggestions on how to interpret such possibilities as
> 
> EPOCH = 'J1991.25 '
> 
> which I assume indicates FK5 coordinates at epoch 1991.25, equinox
> 2000.0.  Such character values for EPOCH do really appear in real
> data;

The FITS Standard, since at least 1993, states that the EPOCH keyword shall no
longer be used, and in any case, must have a floating point value.  I agree with
Peter Bunclark that who ever generates files like this needs to be admonished
and reeducated about the importance of adhering to community standards.  

-Bill Pence