[fitsbits] Proposed Changes to the FITS Standard

[William Thompson]

The SECCHI instrument on the STEREO mission produces some files with table 
extensions, and other files which don't.  The value of the EXTEND keyword is set 
to either T or F to account for this.


Steve Allen wrote:
> On Mon 2007-08-20T01:00:32 -0400, Craig Markwardt hath writ:
> 
>>Has EXTEND ever been optional for files with extensions?
> 
> 
> Has EXTEND ever been relevant for FITS files at all?
> 
> I would like to know of any applications which actually use it.
> 
> If I am not mistaken the CFITSIO toolkit always sets EXTEND to true.
> 
> In my experience there are two types of reading applications:
> Apps which don't know what they would do with an extension, don't even
> look for them, and don't care whether EXTEND is set or not.
> Apps which know that they are expecting extension(s), don't care
> whether EXTEND is set or not, and may fail with an unhelpful message
> if they do not find the particular extension(s) they seek.
> 
> So what applications are there, other than fv, which do not a priori
> know what they are expecting when they read a FITS file?
> In particular, are there any which, when they find extensions, actually
> take different actions based on what they discover?
> 
> These are the sorts of questions which prompted the FITS MIME effort,
> and the sorts of questions which we realized we could not address there.
> 
> --
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-- 
William Thompson
NASA Goddard Space Flight Center
Code 671
Greenbelt, MD  20771
USA

301-286-2040
William.T.Thompson.1 at gsfc.nasa.gov