The muse_exp_align recipe
===============================================================

.. data:: muse_exp_align

Synopsis
--------

Create a coordinate offset table to be used to align exposures during exposure combination.

Description
-----------

Compute the coordinate offset for each input field-of-view image with respect to a reference. The created list of coordinate offsets can then be used in muse_exp_combine as the field coordinate offsets to properly align the exposures during their combination.


Constructor
-----------

.. method:: cpl.Recipe("muse_exp_align")
   :noindex:

   Create an object for the recipe muse_exp_align.

::

   import cpl
   muse_exp_align = cpl.Recipe("muse_exp_align")

Parameters
----------

.. py:attribute:: muse_exp_align.param.rsearch

    Search radius (in arcsec) for each iteration of the offset  computation. (str; default: '30.,4.,2.,0.8') [default="30.,4.,2.,0.8"].
.. py:attribute:: muse_exp_align.param.nbins

    Number of bins to use for 2D histogram on the first iteration of the  offset computation. (long; default: 60) [default=60].
.. py:attribute:: muse_exp_align.param.weight

    Use weighting. (bool; default: True) [default=True].
.. py:attribute:: muse_exp_align.param.fwhm

    FWHM in pixels of the convolution filter. (float; default: 5.0) [default=5.0].
.. py:attribute:: muse_exp_align.param.threshold

    Initial intensity threshold for detecting point sources in sigma above  background RMS. (float; default: 15.0) [default=15.0].
.. py:attribute:: muse_exp_align.param.step

    Increment/decrement of the threshold value in subsequent iterations.  (float; default: 0.5) [default=0.5].
.. py:attribute:: muse_exp_align.param.iterations

    Maximum number of iterations used for detecting sources. (long;  default: 100000) [default=100000].
.. py:attribute:: muse_exp_align.param.srcmin

    Minimum number of sources which must be found. (long; default: 5) [default=5].
.. py:attribute:: muse_exp_align.param.srcmax

    Maximum number of sources which may be found. (long; default: 80) [default=80].
.. py:attribute:: muse_exp_align.param.roundmin

    Lower limit of the allowed point-source roundness. (float; default:  -1.0) [default=-1.0].
.. py:attribute:: muse_exp_align.param.roundmax

    Upper limit of the allowed point-source roundness. (float; default:  1.0) [default=1.0].
.. py:attribute:: muse_exp_align.param.sharpmin

    Lower limit of the allowed point-source sharpness. (float; default:  0.2) [default=0.2].
.. py:attribute:: muse_exp_align.param.sharpmax

    Upper limit of the allowed point-source sharpness. (float; default:  1.0) [default=1.0].


The following code snippet shows the default settings for the available 
parameters.

::

   import cpl
   muse_exp_align = cpl.Recipe("muse_exp_align")

   muse_exp_align.param.rsearch = "30.,4.,2.,0.8"
   muse_exp_align.param.nbins = 60
   muse_exp_align.param.weight = True
   muse_exp_align.param.fwhm = 5.0
   muse_exp_align.param.threshold = 15.0
   muse_exp_align.param.step = 0.5
   muse_exp_align.param.iterations = 100000
   muse_exp_align.param.srcmin = 5
   muse_exp_align.param.srcmax = 80
   muse_exp_align.param.roundmin = -1.0
   muse_exp_align.param.roundmax = 1.0
   muse_exp_align.param.sharpmin = 0.2
   muse_exp_align.param.sharpmax = 1.0


You may also set or overwrite some or all parameters by the recipe 
parameter `param`, as shown in the following example:

::

   import cpl
   muse_exp_align = cpl.Recipe("muse_exp_align")
   [...]
   res = muse_exp_align( ..., param = {"rsearch":"30.,4.,2.,0.8", "nbins":60})


.. seealso:: `cpl.Recipe <http://packages.python.org/python-cpl/recipe.html>`_
   for more information about the recipe object.

Bug reports
-----------

Please report any problems to `Ralf Palsa <usd-help@eso.org>`_. Alternatively, you may 
send a report to the `ESO User Support Department <usd-help@eso.org>`_.

Copyright
---------

This file is part of the MUSE Instrument Pipeline
Copyright (C) 2005, 2015 European Southern Observatory

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, 
MA  02111-1307  USA

.. codeauthor:: Ralf Palsa <usd-help@eso.org>
