calculate_coordinates
=====================

.. py:method:: luminet.isoradial.Isoradial.calculate_coordinates()

   Calculates the angles :math:`alpha` and radii :math:`b` of the isoradial.

   Saves these values in the :py:attr:`angles` and :py:attr:`impact_parameters` attributes.

   :returns: *Tuple[np.ndarray]* --     Tuple containing the angles and radiifor the image on the observer plane.