deletions | additions       diff --git a/fringing.tex b/fringing.tex  index 2a2cf9a..9bf0f83 100644  --- a/fringing.tex  +++ b/fringing.tex 
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\subsection{Checking wavelength calibration}  \label{sec:checkwave}  Both automatic and interactive reductions include a check of the wavelength calibration using the sky lines or telluric absorptions. This is computed by cross-correlating the sky lines either with a frame of sky lines observed in the past, or the telluric absorptions with a telluric model. These frames are stored in the directory ``{\it "{\it  standard}". If the check on the wavelength calibration is performed on 1D frames, the third dimension of the file (produced by the iraf task $apall$) is used. If the check is performed on 2D wavelength calibrated frames, a median along the spatial axis is used. During the interactive reduction some plots are shown to the user for feedback. Examples of these plots are shown in Figs. \ref{fig:check} and \ref{fig:check2}. \subsection{Fringing correction}  \label{sec:fringing}  At the moment fringing correction is only applied to the red part of the spectrum. A KEYWORD keyword  is added to the science frame if the fringing correction is applied. Science frames with name starting with `{\it '{\it  n}' have been corrected for fringing. While reducing the data in interactive mode, if the correction for fringing is poor, users may try to use the option \emph{-- fringing {\tt -{}-fringing  2} and check if this improves the fringing correction. The KEYWORDs keywords  identifying the flat field used to correct for fringing are reported below. \begin{lstlisting}  FLATRED = 'flat_20130401_R642_56463.fits'