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

[Demitri Muna]

On Nov 4, 2014, at 3:44 PM, Mcglynn, Thomas A. (GSFC-6601) <Thomas.A.McGlynn at NASA.gov> wrote:

> Given FITS' rule of once FITS, always FITS, I don't believe that's the appropriate meaning for deprecation
> in this context.  Indeed the standard explicitly defines deprecate as:
>> Deprecate: To express disapproval of. This term is used to refer
>> to obsolete structures that should not be used in new FITS
>> files but which shall remain valid indefinitely.
> stating that deprecated usages are to remain valid forever.  We may wish to be careful not to mix in meanings of deprecate from other contexts, e.g., in programming languages and such.


In that case, "deprecate" really doesn't have much meaning - feature X is currently and will always be supported. "We prefer you don't do this" then has zero practical weight. To "deprecate" something under those terms doesn't mean anything. I'm not attaching a positive or negative connotation to this; that's just what the result is.

> 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.

Cheers,
Demitri

_________________________________________
Demitri Muna

Department of Astronomy
La Ohio State University

http://trillianverse.org
http://scicoder.org



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