[fitsbits] nyphens in TTYPEn

[William Pence]

LC's No-Spam Newsreading account wrote:
> Are there (other than the recommendation to use "only letters, digits,
> and underscore" in 8.3.2. of the FITS standard) any rules or
> recommendations which forbid or deprecate or discourage the use of an
> hyphen or minus sign in the value of TTYPEn keywords of binary tables ?
> 
> A little script of mine is getting screwed up by a FITS file which
> contains TTYPEn like O-INDEX or X-DEC, and (beside fmodhead'ing it) I'd
> like to complain to the author of such file.

The HEASARC has a local convention of using the underscore rather than the 
hyphen as a separator character in the TTYPEn column name values in the FITS 
files that it produces, however there are some cases where the hyphen is the 
obvious choice and is still used (e.g., in columns containing color indices, 
such as 'B-V').  This has meant that when using software, such as fv, that 
performs spreadsheet-type calculations on table columns it is sometimes 
necessary to enclose the column name in quote characters if the name 
contains characters that could be confused with mathematical operators.

Bill Pence
-- 
____________________________________________________________________
Dr. William Pence                          William.D.Pence at nasa.gov
NASA/GSFC Code 662         HEASARC         +1-301-286-4599 (voice)
Greenbelt MD 20771                         +1-301-286-1684 (fax)