[AstroPy] Opening file in PyFits, works in v2.4, not in v3.0.6

[Perry Greenfield]

I generally think that if the interpretation is unambiguous (and for  
nulls, presumably spaces are intended, or at least, cause no change),  
that doing an implicit correction and giving a warning is the right  
thing to do.

Perry

On Apr 3, 2012, at 10:09 AM, Erik Bray wrote:

> On 04/03/2012 09:53 AM, Phil Hodge wrote:
>> On 04/02/2012 07:48 PM, Eddy Barratt wrote:
>>> I have a number of fits files that I cannot open in PyFits 3.0.6,  
>>> though a colleague using 2.4 can open them. PyFits does work on  
>>> other fits files on my computer. I would have assumed that the  
>>> problem is with the files, but they do open using the older  
>>> version and my colleagues using IDL and matlab have managed to  
>>> open them too, so perhaps the issue is with PyFits instead. I've  
>>> attached one of the files, they all have the same error message.
>>>
>>> Here is the error message:
>>>
>>> ...
>>
>> Here is the output from fverify for your file:
>>
>>                        FVERIFY V4.0.0 (CFITSIO V2.470)
>>                        -------------------------------
>>
>> HEASARC conventions are being checked.
>>
>> File: 00000075.fits
>>
>> 1 Header-Data Units in this file.
>>
>> =================== HDU 1: Primary Array ===================
>>
>> *** Error:   Byte #1 in Card#33 is a null(\0).
>> *** Error:   Keyword #6, BSCALE: lower-case exponent d or e is  
>> illegal
>> in value
>>               +1.000000000000e+000.
>> *** Error:   Keyword #7, BZERO: lower-case exponent d or e is  
>> illegal in
>> value
>>               +3.276800000000e+004.
>> *** Error:   Keyword #9, ORIGIN: Value and Comment not separated by  
>> a "/".
>> *** Error:   Keyword #11, FOCALLEN: lower-case exponent d or e is  
>> illegal in
>>               value +1.550000000000e+002.
>> *** Error:   Keyword #12, APERTURE: lower-case exponent d or e is  
>> illegal in
>>               value +0.000000000000e+000.
>> *** Error:   Keyword #22, TEMPERAT: lower-case exponent d or e is  
>> illegal in
>>               value -2.041762134545e+001.
>> *** Error:   Keyword #24, E-GAIN: lower-case exponent d or e is  
>> illegal in
>>               value +1.430000000000e+000.
>> *** Error:   Keyword #25, XPIXSZ: lower-case exponent d or e is  
>> illegal in
>>               value +6.800000000000e-003.
>> *** Error:   Keyword #26, YPIXSZ: lower-case exponent d or e is  
>> illegal in
>>               value +6.800000000000e-003.
>> *** Error:   Keyword #29, EXPOSURE: lower-case exponent d or e is  
>> illegal in
>>               value +3.000000000000e+002.
>> *** Error:   The header fill area is not totally filled with blanks.
>>
>>   32 header keywords
>>
>>   16-bit integer pixels,  2 axes (2184 x 1472),
>>
>> ++++++++++++++++++++++ Error Summary  ++++++++++++++++++++++
>>
>>   HDU#  Name (version)       Type             Warnings  Errors
>>   1                          Primary Array    0         12
>>
>> **** Verification found 0 warning(s) and 12 error(s). ****
>
> Specifically, the problem in this file that PyFITS is breaking on is
> that the header block is not filled with spaces.  According to the  
> FITS
> standard any extra bytes at the end of a header block must be spaces,
> and not nulls as is the case in this file.
>
> I'm not sure what PyFITS should do here.  Should it treat a file like
> this as an error, or should it just produce a warning?  Given that  
> other
> tools (including earlier PyFITS versions) seem to be accepting of  
> this,
> I'm leaning toward the latter.  There's no reason PyFITS can't ignore
> the standard here and read the file anyways.  That said, it's still
> malformatted...
>
> Erik
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