code: def write_skycatalog(self, filename, show_flux=False, show_id=False):
          
          f = open(filename,'w')
          f.write("#Sky positions for cumulative reference catalog. Initial catalog from: "+self.name+'\n')
          header1 = "#RA        Dec"
          header2 = "#(deg)     (deg)"
          if show_flux:
              header1 += "        Flux"
              header2 += "       (counts)"
          if show_id:
              header1 += "        ID        Origin"
              header2 += ""
          header1 += "\n"
          header2 += "\n"
  
          f.write(header1)
          f.write(header2)
  
          show_details = show_flux or show_id
          flux_end_char = ''
          if show_details and show_flux:
              if show_id:
                  flux_end_char = '\t'
  
          for i in range(self.all_radec[0].shape[0]):
              src_line = "{:.7f}  {:.7f}" \
                  .format(self.all_radec[0][i], self.all_radec[1][i])
              if show_details:
                  #src_line += " #"
                  if show_flux:
                      #src_line += " flux: {:.5g}{:s}" \
                          #.format(self.xy_catalog[2][i], flux_end_char)
                      src_line += "  {:.5g}".format(self.xy_catalog[2][i])
                  if show_id:
                      #src_line += " ID: {:d}\torigin: '{:s}'" \
                          #.format(self.xy_catalog[3][i], self.xy_catalog[-1][i])
                      src_line += "  {:d}  {:s}".format(self.xy_catalog[3][i],
                                                        self.xy_catalog[-1][i])
              f.write(src_line + '\n')
          f.close()
docs: Write out the all_radec catalog for this image to a file.