[fitsbits] Proposed Changes to the FITS Standard

[Tim Pearson]

On Aug 17, 2007, at 11:43 AM, Rob Seaman wrote:

>>   There are only 3 proposed new absolute requirements in this list:
>>
>>   1. Keywords that have a value shall not be repeated in a header.
>
> I have many examples (hundreds of thousands?) of files in which
> keywords are repeated.  Rather than the wording in the current
> proposal, I would replace the attempt at a requirement with a strong
> recommendation and a clarification that the final copy of any such
> repeated keyword should take precedence.

I strongly support this. The proposed text makes such files invalid  
FITS, retrospectively. Taking the last instance of a keyword is a  
much more reasonable interpretation. But I note that a program that  
blindly drops all but the last instance may lose the information  
conveyed by: the number of instances, the list of values and their  
order, and any associated comments.

Are there existing applications where a keyword can occur more than  
once with different values, in which more than just the last  
occurrence are intended to carry significant information?

[I understand that technically COMMENT and HISTORY keywords do not  
"have a value".]

- Tim Pearson