deletions | additions       diff --git a/Pipeline steps.tex b/Pipeline steps.tex  index f4a6660..a3b3165 100644  --- a/Pipeline steps.tex  +++ b/Pipeline steps.tex 
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\subsection{Flat fielding}  Flat fielding is still an open question in SEDM pipeline, and so I make the following assumptions, all need to be tested experimentally.   \subsection{Wavelength solution}  This step produces a set of coefficients for each trace. These coefficients return a wavelength solution as a function of pixel position along the trace.   \subsubsection{Input}  \begin{itemize}  \item \verb{\$arcname.fits} -- Arclamp image where a \$arcname is something like Hg, Cd, Zn, Xe, etc...  \item \verb{cat_Hg.fits.txt} -- Is the result of SexTractor on finding the locations of the Mercury lines.  \item \verb{dome.fits_segments.npy} -- Trace locations from trace finding module.  \end{itemize}  \subsubsection{Output}  dome.fits\_segments.npy contains a list (length the number of segments) of dictionaries. Each dictionary contains information about the location of each segment.  \begin{itemize}  \item ok (boolean) -- The segment has more than 50 illuminated pixels  \item mean\_ys ([float]) -- The mean Y location of each pixel in the trace. It's length is usually between 200 to 270 pixels long.  \item xs ([float]) -- The X location of each pixel. It's length is the same as means. The ridgeline of the trace is constructed from the points in (xs, means).  \item trace\_sigma (float) -- The 1 $\sigma$ width of the trace. An in focus image should have a FWHM of about 2.5 pixels and thus sigma should be about 1.06.  \item coeffs_y ([float]) -- A list of polynomial coefficients of order len(poly)-1 that is the best fit line to (xs, means). The bulk of this step's work is to derive poly.  \end{itemize}  \subsection{Extraction}  \subsection{Sky subtraction}  \subsection{Reporting}  This step is not fleshed out yet, but should include a report of:  \begin{enumerate}  \item Spectrograph image quality derived from flats + arcs.  \item Flat field throughput.  \item Telescope image quality derived from IFU images.  \item Flexure over the course of the night.  \item On-sky measured throughput.  \end{enumerate}  \subsection{Object Picker}  A web application that presents the finding chart, a collapsed datacube image, and allows the user to click on the target and sky. The object picker then extracts the spectrum for the user.  \subsubsection{Output}  Directory file structure:  \verb|reductions/\$user/\$object name/\$date/\$time/\$version/|  where \verb{$user} is the user name (for security purposes), \verb{$object} is the name of the target, \verb{$date} and \verb{$time} are the date and time of observation, and \verb{$version}$ is the version number of the reduction.