[AstroPy] How to read and write keyword with no value with astropy.io.fits?

[Thomas Robitaille]

Hi Russell,

Does this mean that the following:

In [8]: header = fits.Header()

In [9]: header['DATE-OBS'] = None,'this date is now known'

In [10]: header
Out[10]: DATE-OBS= '' / this date is now known

should ideally be returning:

In [10]: header
Out[10]: DATE-OBS=    / this date is now known

? Just to make sure I understand, what is the downside of having the
empty quotes?

Cheers,
Tom





On 26 September 2016 at 19:59, Tim Jenness <tim.jenness at gmail.com> wrote:
>
>
> On Mon, Sep 26, 2016 at 11:37 AM, Russell Owen <rowen at uw.edu> wrote:
>>
>> In a FITS header an unknown value can be represented by a keyword with no
>> value (a fact I just learned today and found very surprising). For example:
>>
>> DATE-OBS    / this date is not known
>>
>
> DATE-OBS=       / this date is not known
>
> (without the "=" it's a standard COMMENT. With "=" it's header with an
> undefined value).
>
> --
> Tim Jenness
>
>
> _______________________________________________
> AstroPy mailing list
> AstroPy at scipy.org
> https://mail.scipy.org/mailman/listinfo/astropy
>