RA, DEC and UNSIGNED
Peter Bunclark
psb at ast.cam.ac.uk
Mon Jul 13 04:00:40 EDT 1998
1. Please let's continue to allow RA and DEC in sexadecimal. One of the
most common
quotes is ``FITS is good because when you have problems you can
just more the header'';
the easy readability of the header is seen as a great strength.
The RA and DEC are almost
the most important keywords for end users, and should be in the
format the consumer wants.
2. The lack of unsigned data type was, in my opinion, nearly the biggest
cockup in original
FITS, right behind the EPOCH and DATE problems. The overheads
of
the BZERO hack are:
a) Compute overhead; either an extra bit of arithmetic, or,
more likely, the
reader gives up and casts it all to float, causing lots of
extra arithmetic
and I/O.
b) It *is* a hack; I bet that some of the systems that FITS
was originally
designed for, eg 60-bit machines, need different code from
that on base-2
wordlength machines (? or not?).
c) It brings FITS into disrepute every time you have the
embarrassment of
introducing the system to a new astronomer or software
engineer.
Peter.
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