Index files

Once the pipeline has run for a bit you will find text files in $ORAC_DATA_OUT called index.flat, index.dark amongst others. These list the calibration frames. ORAC-DR uses these to find the most-recent, appropriate calibration. For example, a flat requires that the filter of the flat matches that of the frame being flat fielded, and a dark must have the same exposure time as the target frame; and both must have been taken in the same instrument mode.

Here is an example of a flat index.

#FILTER MODE ORACTIME RDOUT_X1 RDOUT_X2 RDOUT_Y1 RDOUT_Y2 WPLANGLE
flat_Lp98_23 Lp98 STARE 13.3484 1 256 1 256 0
flat_K98_pol0_62 K98+pol NDSTARE 7.971 1 1024 1 1024 0.000
flat_K98_pol22_62 K98+pol NDSTARE 7.971 1 1024 1 1024 22.5
flat_K98_pol45_62 K98+pol NDSTARE 7.971 1 1024 1 1024 45
flat_K98_pol67_62 K98+pol NDSTARE 7.971 1 1024 1 1024 67.5
flat_J98_88 J98 flush_read 7.46111E+00 1 1024 1 1024 0
flat_H98_93 H98 flush_read 7.58330E+00 1 1024 1 1024 0
flat_K98_98 K98 flush_read 7.70559E+00 1 1024 1 1024 0
flat_H98_133 H98 flush_read 8.99034E+00 1 1024 1 1024 0
flat_H98_138 H98 flush_read 9.07139E+00 1 1024 1 1024 0
flat_H98_138_c1 H98 flush_read 9.12074E+00 1 1024 1 1024 0
flat_K98_290_row0 K98 flush_read 1.13094E+01 1 1024 1 1024 0
flat_K98_290_row1 K98 flush_read 1.15080E+01 1 1024 1 1024 0

The first line contains the column headings. ORACTIME is the UT in decimal hours, and WPLANGLE is the polarisation waveplate angle.

In general you should not manipulate these files. Mis-editing can lead to the calibration system breaking down. If you must edit this file, say to exclude a poor dark or an uneven flat, restrict yourself deleting the line corresponding to that calibration file. It's safer to remove the calibration file and recreate a new one with the calibration frames you want by running the pipeline.

If you want to nominate specific calibration frames, overriding those selected from the calibration indices, there is a -calib option for the oracdr command to do this. See calibration options for examples.