Although there are some private data reduction software packages for immediate reduction of FOS data, we recommend the STARLINK packages SCP and SAM, written by J.R. Lewis (described in Starlink User Notes Nos 148 & 149). Alternatively, FIGARO software can be used (the FIGARO commands CDIST and SDIST can be used to track the curved orders). The procedure ( apall} in iraf can also be used for this.