code: def aitoffSphereToImage(lon, lat):
      
      lon = lon - 360.*(lon>180)
      lon = np.radians(lon)
      lat = np.radians(lat)
  
      half_lon = lon/2.
      cos_lat = np.cos(lat)
       
      gamma = (180. / np.pi) * np.sqrt(2. / (1. + (cos_lat * np.cos(half_lon))))
      x = 2. * gamma * cos_lat * np.sin(half_lon)
      y = gamma * np.sin(lat)
      return x, y
docs: Hammer-Aitoff projection (deg).