Radau integration
-----------------

Radau integration differs from normal Gauss integration only in that one of
the interval end points is always included.  Here, the integration is performed
over :math:`\mu =` the cosine of the inclination relative to the normal, and the
point :math:`\mu=1` is always included.

This has the advantage that no :math:`\phi`-integration (integration over azimuth)
is needed for that inclination, which also generally carries the largest
specific radiation intensity.

.. toctree::
   :maxdepth: 4