code: def estimate_angle(coord, angle, new_frame, offset=1e-7):
      
      delta = delta_coord(coord, angle, offset)
      new_coord = coord.transform_to(new_frame)
      new_delta = delta.transform_to(new_frame)
      return new_coord.position_angle(new_delta).deg
docs: https://github.com/astropy/astropy/issues/3093