File format

You are unlikely to need to worry about the format of the arc lines files. These files are produced by arc and used by iarc. For details of the format please see the FIGARO documentation.

A typical file looks like this (the arc lines for the short-J grism with the argon lamp):

      4 lines identified from /home/spt/oracdr_cal/uist/grisms/arcs/short_J_Ar

        Channel   Wavelength   Calculated  Discrepancy  Line#
        67.1694   11671.9004   11671.9150       0.0146      1    
       185.4290   11491.2002   11491.1787      -0.0215      2    
       727.9574   10676.5000   10676.5186       0.0186      3    
       866.0963   10472.9004   10472.8877      -0.0127      4    

      RMS error:       0.02, Line width used:  2.00

      Order of fit:   2

      0.4040299644214860E-04-0.1538503512984496E+01 0.1177507315490152E+05

The only part of this file to be directly used by any of the recipes (rather than by a FIGARO task) is the final line, giving the polynomial wavelength fit, which is used to calculate the wavelength range to which the spectra should be scrunched.