Subject: Keywords longer than eight characters

From: thompson at stars.gsfc.nasa.gov (William Thompson, code 682.1, x2040)
Date: 18 Jun 92 17:53:00 GMT

Is there any kind of defacto way to store keywords longer than eight characters
in a FITS header?  Someone suggested using the COMMENT keyword followed by the
non-standard keyword, although another possibility is using the null keyword
(eight blanks).  Is this what other people do?

I'm not talking about keywords essential to reading and scientifically
processing the data.  I'm more interested in storing engineering information
about the state of the instrument.  It would be desirable to retain the
original mnemonic names used by the engineers.  Important information could
also be replicated using more standard FITS keywords.

Although it's obviously legal to put anything in a COMMENT field, I'm
interested in knowing what other people do.

Bill Thompson

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From: forveill at gag.observ-gr.fr (Thierry Forveille)
Date: Fri, 19 Jun 1992 09:14:43 GMT

Althought I never had to face that specific problem, I would suggest you
store the information with a standard keyword and append the original
mnemonic as an end of line comment (after the /). This is standard too,
and the information will be easier to extract for a general FITS handling
program if you later want to plot this engineering information. Extracting
the information from a COMMENT or blank keyword would probably need ad hoc
(though trivial) modifications of the program. Of course the standard keyword
need not be particularly informative and something line ENGIN001 to ENGIN999
would work.

	Thierry Forveille
	Observatoire de Grenoble