[fitsbits] Dataset identifications.

[Thierry Forveille]

Thomas McGlynn writes:
 > My feeling is that if the two elements of data are so tightly
 > coupled that they would normally be put in the same FITS file,
 > then one would consider them to be the same dataset. At the HEASARC
 > datasets generally comprise more than one FITS file.  I can't think
 > off the top of my head of an example where a given FITS file would
 > naturally split up into multiple IDs.
 > 
The need I had in mind is further down the line than either telescopes or
places like HEASARC: an astronomer builds a single FITS file with all the
images+photon-lists+tables+... that he uses in a given A&A paper, gives
them a new DS_IDENT of course (probably derived from the bib code of the
paper) in the primary header, and keeps the original DS_IDENT for each
extension. Or actually, that merging might end up being done by the 
journals.

It's a slight extension of what you proposed and it might perhaps never
actually develop into reality, but I see no major reason to outright 
forbid that use.