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from spam import *

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def make_mosaic():
  
  # copy all .RES.FITS files into the 'fits' subdirectory 
  mosaic_center = hmsdms_to_degdeg( [ 10,0,0, 15,0,0 ] )
  mosaic_size = [ 5, 5 ] # initial mosaic size in degrees before cropping
  mosaic_name = 'MY-MOSAIC'
  restoring_beam = [ 10.,10.,0. ] # BMAJ, BMIN, BPA; can be smaller than largest BMAJ
  beam_radius = 0.8 # primary beam radius to include per pointing in degrees
  res_fits_search_string = os.getenv( 'PWD' ) + '/fits/*.RES.FITS'
  
  # create pointing file
  pointing_cat = [ [ 'POINTING', 'RA', 'DEC' ] ]
  dt = datetime.datetime.now()
  dt_string = '%4d%02d%02d_%02d%02d%02d' % ( 
      dt.year, dt.month, dt.day, dt.hour, dt.minute, dt.second )
  fits_file_names = glob.glob( res_fits_search_string )
  fits_file_names.sort()
  for fits_file_name in fits_file_names:
    pointing_name = fits_file_name.split( '/' )[ -1 ]
    index = pointing_name.index( '.RES.FITS' )
    pointing_name = pointing_name[ : index ].replace( '_', '.' ) + '.' + dt_string
    link_file_name = '%s/fits/%s.RES.FITS' % ( os.getenv( 'PWD' ), pointing_name )
    link_file( fits_file_name, link_file_name )
    header = read_fits_header( fits_file_name )
    ra = None
    dec = None
    for line in header:
      words = line.split()
      if ( words[ 0 ] == 'OBSRA' ):
        ra = float( words[ 2 ] )
      if ( words[ 0 ] == 'OBSDEC' ):
        dec = float( words[ 2 ] )
    if ( ( ra == None ) or ( dec == None ) ):
      raise error( 'could not find OBSRA/OBSDEC in FITS header of %s' % 
          ( pointing_file_name ) )
    pointing_cat.append( [ pointing_name, ra, dec ] )
  pointing_file_name = os.getenv( 'PWD' ) + '/fits/pointings.rdb'
  write_starbase_catalog( pointing_cat, pointing_file_name )
  
  # create mosaic
  mosaic = create_mosaic( mosaic_name, mosaic_center, mosaic_size,
      pointing_fits_path = os.getenv( 'PWD' ) + '/fits',
      pointing_file_name = os.getenv( 'PWD' ) + '/fits/pointings.rdb', 
      get_pointings = False, restoring_beam = restoring_beam, make_beam_plot = False,
      beam_radius = beam_radius, max_image_size = 16000, convolve_background = True,
      pixels_per_beam = 4., allow_missing_pointings = True, do_galactic = False )
  
  # crop/remove blank edges
  fits_path = os.getenv( 'FIT' )
  mosaic_file_name = '%s/%s.MOSAIC.FITS' % ( fits_path, mosaic_name )
  cropped_image = crop_image( mosaic )
  mosaic.zap()
  write_fits_image( cropped_image, mosaic_file_name )
  cropped_image.zap()
  
  # clean up
  for [ pointing_name, ra, dec ] in pointing_cat[ 1 : ]:
    link_file_name = '%s/%s.RES.FITS' % ( fits_path, pointing_name )
    unlink_file( link_file_name )
  remove_file( pointing_file_name )
  
  return

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