Hi Bill,

I've revised the documentation about this convention to try to
address all the comments that have been received so far. Please
see the new PDF (or postscript) documentation file available from
the FITS Registry at
http://fits.gsfc.nasa.gov/fits_registry.html.

Certainly an improvement. If we can agree that a broader discussion
of implementing long string support within the standard will follow,
I withdraw any objections from this end to the convention being
registered.

I don't really see any technical problem with writing the CHECKSUM
keyword as a continuation over 2 (or more) keywords. The algorithm
for initializing the header and calculating the CHECKSUM keyword
value(s) would need to be modified slightly, but it would still
follow the same basic procedure.

Indeed, the FITS checksum encoding could accommodate such a
complication, but both writers (or generalized keyword editors) and
readers would have to know about the 32-bit alignment requirements
for CHECKSUM keywords. To modify my previous example a bit, this
keyword:

CHECKSUM= 'nADTnADQnADQnADQ' / ASCII 1's complement checksum

is not the same as this expression of overtly the same value:

CHECKSUM= 'nADTnADQn& ' / ASCII 1's complement checksum
CONTINUE 'ADQnADQ'

The 32-bit integer alignment is different, breaking the 1's
complement legerdemain. Other keywords won't have this peculiar
requirement, but additional semantic or logistical complications can
be anticipated.

- Rob