.. _extraction:

Spectral Extraction (`~slitlessutils.extract`)
==============================================


Introduction
------------
Spectral extraction refers to the conversion of two-dimensional spectroscopic image(s) to a one-dimensional, fluxed spectrum.  While there are many discussions of this process in the literature (e.g. `Horne 1986 <https://ui.adsabs.harvard.edu/abs/1986PASP...98..609H/abstract>`_), many of these focus on *aperture*-based spectrographs (e.g. long-slits or fibers).  Certainly, many of the aspects of the reduction/analysis of these data are applicable or have corollaries to slitless spectrographs, but the lack of an aperture leads to many complicating factors.


Preprocessing WFSS Images
-------------------------

Before one can extract WFSS data, there are several *preprocessing* steps that should considered.  Below is a table that lists the three major preprocessing steps that one should implement for their data:


.. toctree::
	:titlesonly:

	astrometry.rst
	background.rst
	cosmicrays.rst


How to extract the data?
------------------------
`Slitlessutils` offers two modes for extracting one-dimensional spectra from a collection of WFSS images.  The primary difference between the two is based on the number of distinct orients (or dispersion directions) available.

.. toctree::
	:titlesonly:

	single.rst
	multi.rst