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How to get solar wind parameter at Moon
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There are two spacecraft ACE and WIND to monitor the solar wind.

ACE
===

A simplest way of getting ACE data is using :mod:`pyana.swim.ace` module.
:class:`pyana.swim.ace.AceMoon` class is for the solar wind parameter at Moon.
Please make sure that the shifted data file (usually ``ace2moon.dat``) is
existing and correctly specified as ``[swim]/acemoon`` entry of ``~/.pyanarc`` file.

.. code-block:: py

        >>> from pyana.swim.ace import AceMoon
        >>> import datetime
        >>> t0 = datetime.datetime(2009, 1, 29, 13, 0, 0)
        >>> t1 = datetime.datetime(2009, 1, 29, 13, 10, 0)
        >>> a = AceMoon()
        >>> prms = a.getAverage(t0, t1)

The returned value is a tuple
``(ave_np, std_np, ave_vx, std_vx, ave_vy, std_vy, ave_vz, std_vz, ave_Tp, std_Tp, ave_rHe, std_rHe, ave_bx, std_bx, ave_by, std_by, ave_bz, std_bz)``

The parameters are calculated by the shift of the solar wind condition considering
the distance between ACE and the Moon and the solar wind velocity itself.

WIND
====

The simplest way of getting WIND data is using :mod:`pyana.swim.wind` module.
Here :class:`pyana.swim.wind.WindMoon` is the interface class for users to get the
key parameters of the Moon.
The data should be prepared prior to the use, see documentation in :mod:`pyana.swim.wind`.
Also, pyanarc should be set.  ``swim`` section ``windmoonpath`` is to be set.

Code block to take the data is rather simple.

.. code-block:: py

        >>> from pyana.swim.wind import WindMoon
        >>> import datetime
        >>> t0 = datetime.datetime(2009, 1, 29, 13, 0, 0)
        >>> t1 = datetime.datetime(2009, 1, 29, 13, 10, 0)
        >>> prms = WindMoon.get_average(t0, t1)


The returned values is three element tuple.
First element is the time at the Moon, the second is the average, and the thrid is the variance.
Average and variance has 7 elements (see :mod:`MoonData.label_array`), but the first three is
density, velocity and thermal velocity.