The data reduction is described in this document.

The PEPSI  “Software for Stellar Spectroscopy” (SDS4PEPSI) is a generic package in C++ under Linux based on the 4A package for the NOT spectrograph SoFin (Ilyin 2000, PhD thesis, Univ. Oulu). The data reduction pipeline is implemented on a virtual machine with 32 processors at mountain.

The incorporated Image Processing and Reduction Toolkit (IPRT) within SDS4PEPSI relies on adaptive selection of parameters by using statistical inference and robust estimators. The standard components include bias overscan detection and subtraction, scattered light surface extraction and subtraction, definition of echelle orders, weighted extraction of spectral orders, wavelength calibration, and a self-consistent continuum fit to the full 2D image of extracted orders.

Details are given in Paper I in A&A 612, A44.

The final product will look like this: