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foswcorr stsdas.hst_calib.fos



foswcorr -- Update the FOS calibrated wavelength file.


foswcorr image


The foswcorr task is a script which updates FOS calibrated wavelength files (.c0h/.c0d) to account for systematic changes in the zero-point of the wavelength scale. This task is only applicable to spectroscopic or rapid readout data. At this time foswcorr is also only applicable to observations acquired with the blue detector. No additional calibration files are necessary in order to run this task. If the input image is a multi-group GEIS file, all of the groups will be updated appropriately.

Upon invocation, foswcorr will first make a copy of the input image file for safety. The input image must be in GEIS format (.c0h/.c0d), and therefore, will have an ipppssoot.c0h/c0d filename; the safe copy will be named ipppssoot_orig.c0h/c0d. If an ipppssoot_orig.c0h/c0d file already exists in the current directory, the task will warn the user and discontinue processing. If this should occur, the original input image file remains unchanged.


input [string]
Image file (.c0h) which should be updated.


1. Update the wavelengths for observation y09t0p01t which is a blue observation using the L65 grating taken in spectroscopy mode.

  fo> foswcorr y09t0p01t.c0h

At the completion of this execution, the original file will be updated with the proper wavelengths, and there will be new files y09t0p01t_orig.c0h/c0d in the current directory.

2. Update the wavelengths for observation y09t0g01t which is a blue observation using the PRISM grating taken in spectroscopy mode.

  fo> foswcorr y09t0g01t.c0h
ERROR: This correction is not appropriate for PRISM data.

The error message is generated by the script as this correction is not applicable to PRISM data.


This task is not applicable to spectropolarimetry or prism data. Also, at this time this task only applies to observations acquired with the blue detector.

If the task should abort prematurely, the temporary files created in the tmp$ directory will not be deleted, and the user will have to do this manually.


The algorithm coded in this script is based upon Instrument Science Report CAL/FOS-149 by Rosa, M., Kerber, F., and Keyes, C. (June 1998).

Author: Michele D. De La Pena, SSG.


For assistance using this or any other tasks, please contact or call the help desk at 410-338-1082.


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