title: Is something wrong with my fits file?
body: <p>I am currently trying to display this fits image, but I keep running into different errors. At first it couldn't print the non-ASCII characters in the header so I went ahead and deleted them (they seemed like just blank spaces in the header, it started a ' but didn't it close it with another ' so I figured it was that and put another ' to close it (?), specifically in the "BUNIT" section and the "INSTRU" one). This is how I'm trying to show the image:</p>
  
  <pre><code>from astropy.io import fits
  from astropy import wcs
  import matplotlib.pyplot as plt
  
  fig = plt.figure()
  ax = fig.add_axes(111, projection=wcs.WCS('uwc.fits'))
  
  ax.imshow(fits.getdata('uwc.fits'))
  </code></pre>
  
  <p>This is how the header looked after I deleted the whole BUNIT and INSTRU thing:</p>
  
  <pre><code>SIMPLE  =                    T          / FILE IN FITS FORMAT
  BITPIX  =                   16          / SIZE OF PIXELS
  NAXIS   =                    3          / NUMBER OF AXES
  NAXIS1  =                  181          /
  NAXIS2  =                   91          /
  NAXIS3  =                    1          /
  BSCALE  =          .831495E-02          / REAL = TAPE*BSCALE+BZERO
  BZERO   =          .319702E+02          / ZERO CORRECTION
  BUNIT   = '        '                    / UNITS OF BRIGHTNESS
  DATAMAX =          .302206E+03          / MAXIMUM DATA VALUE IN FILE
  DATAMIN =          .319702E+02          / MINIMUM DATA VALUE IN FILE
  BLANK   =               -15751          / BLANK VALUE (C279 HEX)
  OBJECT  = 'C Band   (0.16-0.2'          / IMAGE NAME
  DATE    = '05/02/89'                    / DATE
  DATOBS  = '        '                    / DATE OBJECT OBSERVED
  INSTRU  = '                  '          / INSTRUMENT
  OBSERV  = '                  '          / NAME OF OBSERVER
  ORIGIN  = 'PENN STATE'                  / TAPE ORIGIN
  CTYPE1  = 'GLON-AIT'                    /
  CRVAL1  =              .000000          /
  CRPIX1  =            91.000010          /
  CDELT1  =            -1.800000          /
  CROTA1  =              .000000          /
  CTYPE2  = 'GLAT-AIT'                    /
  CRVAL2  =              .000000          /
  CRPIX2  =            46.000000          /
  CDELT2  =             1.800000          /
  CROTA2  =              .000000          /
  CTYPE3  = '        '                    /
  CRVAL3  =              .000000          /
  CRPIX3  =              .000000          /
  CDELT3  =              .000000          /
  CROTA3  =              .000000          /
  END
  </code></pre>
  
  <p>Then it had another error. Specifically it looked like this:</p>
  
  <pre><code>SingularMatrixError: ERROR 3 in wcsset() at line 2218 of file      
  cextern/wcslib/C/wcs.c:    
  Linear transformation matrix is singular.
  ERROR 3 in linset() at line 638 of file cextern/wcslib/C/lin.c:
  PCi_ja matrix is singular.
  
  
  &lt;Figure size 432x288 with 0 Axes&gt;
  </code></pre>
  
  <p>I don't know what this error means and I don't know how to fix the header anymore. I had tried deleting the whole CTYPE3 to CROTA3 section but it didn't work out because a "TypeError: from_bounds() argument after * must be an iterable, not int" came up. Any help or reference here will be appreciated, thank you!!</p>