Index files

When calibration files are reduced they are listed in an index file in the directory containing the reduced data. Where separate index files are used by imaging and spectroscopy recipes (e.g. index.flat_im and index.flat_sp) the spectroscopy files will be used. Two of the index files used include more information than just the filename of the calibration frames.

The index.iar file indexes not only the .iar files generated by FIGARO iarc containing the wavelength calibration of every row but also the wavelength range (in Angstroms) to which the spectra should be scrunched. The filename and the minimum and maximum wavelengths are separated by colons.

      #GRISM ORACTIME
      u20030131_00011_bpf.iar:14081:24988 HK+ifu 4.911111
      u20030131_00067_bpf.iar:20159:22489 short_K+ifu 7.316945

Similarly, the index.offset file contains both the name of the file from which the offset value was measured and the offset itself separated by a colon.

      #GRISM ORACTIME
      u20030131_00010.I1:26 HK+ifu 4.905833
      u20030131_00066.I1:19 short_K+ifu 7.297500

There is also one index file, index.arlines, which is not stored in the reduced data directory but in the calibration directory ( $ORAC_DATA_CAL). This is the index of the arc lines lists (see section ), which are static calibration files.