[AstroPy] Pywcs not reading transformation matrix correctly

Oliver King ogk@astro.caltech....
Thu Jul 26 12:15:22 CDT 2012


This might be the reason:
0.0.dev1119

I'll try updating to the latest version.

On Jul 26, 2012, at 10:10 AM, Thomas Robitaille wrote:

> Which version of Astropy are you using?
> 
> import astropy
> print astropy.__version__
> 
> I'm using the latest developer version, and it seems to be working:
> 
> CD_11  CD_12: -7.7588993045300006e-05 4.5042903792000001e-07
> CD_21  CD_22: -3.9690360471000002e-07 -7.7631469153300006e-05
> CRVAL    : 343.48506545599997 16.146689138399999
> CRPIX    : 1094.26737976 1037.5606839899999
> NAXIS    : 0.0 0.0
> 
> If you are using v0.1, could you try updating to the latest git
> version to see if it was fixed?
> 
> Thanks!
> Tom
> 
> On 26 July 2012 19:03, Oliver King <ogk@astro.caltech.edu> wrote:
>> Hi JB,
>> 
>> The WCS does not have a RADECSYS keyword; the CTYPE is TAN-SIP. Here are all the WCS parameters (excluding the polynomial coefficients). This is an image which has had a WCS attached by the astrometry.net software.
>> 
>> CTYPE1  = 'RA---TAN-SIP' / TAN (gnomic) projection + SIP distortions
>> CTYPE2  = 'DEC--TAN-SIP' / TAN (gnomic) projection + SIP distortions
>> WCSAXES =                    2 / no comment
>> EQUINOX =               2000.0 / Equatorial coordinates definition (yr)
>> LONPOLE =                180.0 / no comment
>> LATPOLE =                  0.0 / no comment
>> CRVAL1  =        343.485065456 / RA  of reference point
>> CRVAL2  =        16.1466891384 / DEC of reference point
>> CRPIX1  =        1094.26737976 / X reference pixel
>> CRPIX2  =        1037.56068399 / Y reference pixel
>> CUNIT1  = 'deg     ' / X pixel scale units
>> CUNIT2  = 'deg     ' / Y pixel scale units
>> CD1_1   =   -7.75889930453E-05 / Transformation matrix
>> CD1_2   =     4.5042903792E-07 / no comment
>> CD2_1   =    -3.9690360471E-07 / no comment
>> CD2_2   =   -7.76314691533E-05 / no comment
>> IMAGEW  =                 2048 / Image width,  in pixels.
>> IMAGEH  =                 2048 / Image height, in pixels.
>> 
>> Cheers,
>> Oliver
>> 
>> On Jul 26, 2012, at 9:58 AM, Jean-Baptiste Marquette wrote:
>> 
>>> 
>>> Hi Oliver,
>>> 
>>>> Is this a known bug? Is there a workaround or do I need to manually edit my FITS file headers?
>>> 
>>> What are your CTYPEn and RADECSYS ?
>>> 
>>> Cheers
>>> JB
>> 
>> ------
>> Oliver King
>> Astronomy Department, Caltech
>> +1-626-395-4197
>> 
>> _______________________________________________
>> AstroPy mailing list
>> AstroPy@scipy.org
>> http://mail.scipy.org/mailman/listinfo/astropy

------
Oliver King
Astronomy Department, Caltech
+1-626-395-4197



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