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

[Demitri Muna]

On Nov 4, 2014, at 2:48 PM, Phil Hodge <hodge at stsci.edu> wrote:

> I wouldn't use a FITS writer that changed my data.


Agreed. A FITS writer should not write an invalid FITS file or one that does not meet the spec. If a file does meet the spec, reading it in full and writing it back out should not change any data.

This does not preclude warning the user what is *preferred*.

> 2. Angstrom and erg are deprecated in the IAU list

Deprecated means (to me) that you should not be using feature X, but if you do (and you can) /don't be surprised if in the future if your file that uses feature X no longer works (which in this case could mean the file can be read but will not be written out the same way as above).

That said, I don't see why an updated FITS format can't attach any unit (e.g. anything defined in astropy.units) to any column (barring ambiguity of course).

Demitri

_________________________________________
Demitri Muna

Department of Astronomy
An Ohio State University

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



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