code: def get_alt_az(utc_time, lon, lat):
      
      lon = np.deg2rad(lon)
      lat = np.deg2rad(lat)
  
      ra_, dec = sun_ra_dec(utc_time)
      h__ = _local_hour_angle(utc_time, lon, ra_)
      return (np.arcsin(np.sin(lat) * np.sin(dec) +
                        np.cos(lat) * np.cos(dec) * np.cos(h__)),
              np.arctan2(-np.sin(h__), (np.cos(lat) * np.tan(dec) -
                                        np.sin(lat) * np.cos(h__))))
docs: Return sun altitude and azimuth from *utc_time*, *lon*, and *lat*.
      lon,lat in degrees
      What is the unit of the returned angles and heights!? FIXME!