[AstroPy] Need Help about Astropy.table.Table.write

[Thomas Robitaille]

Hi Guang,

To overwrite a file, you can use:

  cat.write('new.fits', format='fits', overwrite=True)

For the unit, the issue is that ``ct`` is not a valid unit according to
the FITS standard. The 'correct' unit for FITS is ``count``. We may be
overly strict at the moment in that Table.write will simply crash if a
unit is not standard-compliant, when we could simply emit a warning and
still write it out, so I will open an issue for that.

So in the mean time, the solution is to do:

  cat['name'].unit = 'count'

where 'name' is the name of the problematic column. Do this before
writing it out to FITS.

Cheers,
Tom

Guang Yang wrote:
> Hi All,
> 
> I've found Astropy.table.Table.write is unable to write tables with arbitrary units. 
> For example, after using sextractor to generate a fits table, 
> 
> from astropy.table import Table
> cat = Table.read('sextractor_output.fits', format='fits')
> cat.write('new.fits', format='fits')
> 
> Then, the error comes: Unit u'ct' is not part of the FITS standard. And I've found no parameter to avoid the unit problem.
> 
> Also, when the file 'new.fits' already exists, there seems to be no keyword to overwrite the file.
> 
> Thanks,
> Guang Yang
> 
>  
> 
> 
> 
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