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<p>I'm hoping this question is relatively straightforward for those proficient with IDL and python and fits file handling (I'm using the astropy.fits module)</p>
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<p>I'm looking to find an equivalent to SXPAR (<span style="font-size: 12pt;">whose function is to o</span><span style="font-size: 12pt; white-space: pre-wrap;">btain the value of a parameter in a FITS header</span><span style="font-size: 12pt;">)</span><span style="font-size: 12pt;">
from IDL into python</span><span style="font-size: 12pt;">...</span></p>
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<p><a href="http://idlastro.gsfc.nasa.gov/ftp/pro/fits/sxpar.pro" id="LPlnk253682">http://idlastro.gsfc.nasa.gov/ftp/pro/fits/sxpar.pro</a><span style="font-size: 12pt;"><br>
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<a id="LPUrlAnchor_14554540429860.03254285338334739" href="http://idlastro.gsfc.nasa.gov/ftp/pro/fits/sxpar.pro" target="_blank" style="text-decoration: none;" title="http://idlastro.gsfc.nasa.gov/ftp/pro/fits/sxpar.pro
Cmd+Click or tap to follow the link">"sxpar.pro"
- idlastro.gsfc.nasa.gov</a></div>
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idlastro.gsfc.nasa.gov</div>
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Apostrophes are stripped ; from strings. If the parameter is logical, 1b is ; returned for T, and 0b is returned for F. ; If Name was of ...</div>
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<p><span style="font-size: 12pt; white-space: pre-wrap;">This is the original code in IDL:</span><br>
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nxpix_uw1_ext1 = sxpar(hima_sk_uw1_ext1,<span style="color:#272ad8">'NAXIS1'</span>)</p>
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nypix_uw1_ext1 = sxpar(hima_sk_uw1_ext1,<span style="color:#272ad8">'NAXIS2'</span>)</p>
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<p><span style="white-space:pre-wrap; font-size:12pt">This is my conversion attempt into python using astropy.fits:</span></p>
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<span style="color:#bb2ca2">from</span> astropy.io <span style="color:#bb2ca2">import</span> fits</p>
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hima_sk_um2 = fits.open(<span style="color:#272ad8">''</span>) #Will contain the directory extension to the fits/img file I wish to open</p>
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# Compute the size of the images (you can also do this manually rather than calling these keywords from the header):</p>
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nxpix_um2_ext1 = hima_sk_um2[<span style="color:#272ad8">1</span>].header[<span style="color:#272ad8">'NAXIS1'</span>]</p>
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nypix_um2_ext1 = hima_sk_um2[<span style="color:#272ad8">1</span>].header[<span style="color:#272ad8">'NAXIS2'</span>]</p>
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<p><span style="white-space:pre-wrap; font-size:12pt">Firstly, is this correct? And secondly, is this the best way to handle an extension value?</span></p>
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<p><span style="white-space:pre-wrap; font-size:12pt">Any advise would be warmly received.</span></p>
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<p><span style="white-space:pre-wrap; font-size:12pt">Many thanks,</span></p>
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<p><span style="white-space:pre-wrap; font-size:12pt">Michael</span></p>
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