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* ARCES has a small aperture, giving a very short “slit”. Sky is difficult, if not impossible, to detect/subtract

* as with many echelle spectrographs, scattered light is present in an amount that varies in time, likely to do changing levels of contamination on the detector

* IRAF-based alternatives

• Attached below is the IRAF Data Reduction Guide for ARCES by Julie Thorburn of University of Chicago. This document is meant to be a guide to get the user started with echelle data reduction with suggested parameters for certain IRAF tasks. There are very useful and important descriptions of the peculiarities of the ARCES data, and the user is recommended to read this document before forging ahead with the data processing.
• Chris Churchill's Introduction of Echelle Data Reduction using IRAF is an excellent document describing in detail the process of reducing, extracting and calibrating echelle spectra. Although the document is for the Hamilton spectrograph, many of the steps can be applied to ARCES spectra.
• Wako Aoki's manual on reducing Subaru echelle data is also provided here. A different method of continuum flattening your spectra is described in this manual.
• K. Kinemuchi's ARCES echelle data reduction cookbook is available, along with auxiliary files that will aid in the data reduction process.
• J. Mckeever's python script for reduction is available as an attachment, as well as a .tgz which includes all the necessary files to run. See K. Kinemuchi guide for details of the process.

* pyvista

* PypeIt

• G. Catanzaro's spectra atlas of atmospheric telluric lines provides a great resource to identify the telluric lines in the ARCES data.