The fors_dark recipe
===============================================================

.. data:: fors_dark

Synopsis
--------

Compute master dark frame

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

This recipe is used to combine input raw DARK frames into a master dark
frame by subtracing the master bias and using the given stacking method.

The overscan regions, if present, are removed from the result.


Input files
^^^^^^^^^^^^
::

  DO category:               Type:       Explanation:         Required:
  DARK                       Raw         Dark frame              Y
  MASTER_BIAS                FITS image  Master bias             Y

Output files
^^^^^^^^^^^^
::

  DO category:               Data type:  Explanation:
  MASTER_DARK                FITS image  Master dark frame


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

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

   Create an object for the recipe fors_dark.

::

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

Parameters
----------

.. py:attribute:: fors_dark.param.stack_method

    Frames combination method (str; default: 'median') [default="median"].
.. py:attribute:: fors_dark.param.minrejection

    Number of lowest values to be rejected (int; default: 1) [default=1].
.. py:attribute:: fors_dark.param.maxrejection

    Number of highest values to be rejected (int; default: 1) [default=1].
.. py:attribute:: fors_dark.param.klow

    Low threshold in ksigma method (float; default: 3.0) [default=3.0].
.. py:attribute:: fors_dark.param.khigh

    High threshold in ksigma method (float; default: 3.0) [default=3.0].
.. py:attribute:: fors_dark.param.kiter

    Max number of iterations in ksigma method (int; default: 999) [default=999].


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

::

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

   fors_dark.param.stack_method = "median"
   fors_dark.param.minrejection = 1
   fors_dark.param.maxrejection = 1
   fors_dark.param.klow = 3.0
   fors_dark.param.khigh = 3.0
   fors_dark.param.kiter = 999


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

::

   import cpl
   fors_dark = cpl.Recipe("fors_dark")
   [...]
   res = fors_dark( ..., param = {"stack_method":"median", "minrejection":1})


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

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

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

Copyright
---------

This file is currently part of the FORS Instrument Pipeline
Copyright (C) 2002-2011 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  02110-1301  USA


.. codeauthor:: Jonas M. Larsen <usd-help@eso.org>