[fitsbits] Question on angstrom and erg units in FITS standard

[Thierry.Forveille at ujf-grenoble.fr]

Quoting Demitri Muna <demitri.muna at gmail.com>:
>> Given FITS' rule of once FITS, always FITS
>
> The closer this is hewed to, the more likely that FITS itself will  
> be deprecated. I'm strongly 100% in favor of all future software  
> being able to read all (valid) FITS files that currently exist, but  
> the idea that all past software being able to read any future FITS  
> file is a sure path to obsolescence.
>
The latter has never been the case, with the only requirement
being that old FITS files remain readable.