def copy_ccube(ccube, outsrcmap, hpx_order):
        """Copy a counts cube into outsrcmap file
        reducing the HEALPix order to hpx_order if needed.
        """
        sys.stdout.write("  Copying counts cube from %s to %s\n" % (ccube, outsrcmap))
        try:
            hdulist_in = fits.open(ccube)
        except IOError:
            hdulist_in = fits.open("%s.gz" % ccube)

        hpx_order_in = hdulist_in[1].header['ORDER']

        if hpx_order_in > hpx_order:
            hpxmap = HpxMap.create_from_hdulist(hdulist_in)
            hpxmap_out = hpxmap.ud_grade(hpx_order, preserve_counts=True)
            hpxlist_out = hdulist_in
            #hpxlist_out['SKYMAP'] = hpxmap_out.create_image_hdu()
            hpxlist_out[1] = hpxmap_out.create_image_hdu()
            hpxlist_out[1].name = 'SKYMAP'
            hpxlist_out.writeto(outsrcmap)
            return hpx_order
        else:
            os.system('cp %s %s' % (ccube, outsrcmap))
            #os.system('cp %s.gz %s.gz' % (ccube, outsrcmap))
            #os.system('gunzip -f %s.gz' % (outsrcmap))
        return None
Copy a counts cube into outsrcmap file
        reducing the HEALPix order to hpx_order if needed.