calacs -- Process ACS images through the different steps of the ACS Pipeline calibration.
- Input file name or association table name to be processed through calacs.
- (quiet = no)
- Print messages only to trailer files?
- (savetmp = no)
- Save all temporary files created by calstis?
- (verbose = yes)
- Print time stamps at each operation as it takes place?
The task calacs provides routine calibration for ACS data. Both single images and sets of observations specified by an association table can be processed through calacs. The task determines whether CCD or MAMA data will be processed. calacs starts processing CCD data using the acsccd task. Associated data for CR-SPLIT observations will then be combined using acsrej. MAMA data, single CCD data that have been processed with acsccd and CR-combined products from acsrej then get calibrated using acs2d. RPT-OBS associated data (both MAMA and CCD) would then get combined using acssum.
By setting the appropriate switches in the primary header of the input image, either one or all of the functions specified above can be performed.
INPUT AND OUTPUT IMAGES. Association tables are read and interpreted to determine what uncalibrated _raw.fits files should be processed. The relationship between the input files and the output products are also specified in the table depending on whether it was a CR-SPLIT, RPT-OBS or DITHER-pattern observation set.
The input ACS images consist of FITS files, with three extensions in an image set: science (EXTNAME=SCI), error (ERR), and data quality (DQ). Each FITS file contains only one obsrvation, with association tables providing the relationship between any associated images.
The name of the output file is normally set by the task itself for single input images or by the association table. Single image output filenames are created by appending to the rootname of the input file the appropriate suffix that will indicate the last step in the calibration process that the file went through. The current output filename suffixes are:
- The flat fielded science data. The output file has been fully calibrated with acsccd+acs2d for CCD data or with just acs2d for MAMA data. This suffix is used for all MAMA observations.
- The cosmic-ray rejected and flat fielded science data. Valid only for CCD observations that have been cosmic-ray rejected.
- The summed product of all the flat-fielded RPT-OBS observations.
REFERENCE FILES and PROCESSING STEPS
The names of the reference files (images and tables) to be used by calacs (and consequently by all the other processing tasks) are specified in the primary header of the input image, under the section CALIBRATION REFERENCE FILES.
When an environment variable is used as part of a reference file name (e.g. "jref" in PFLTFILE = "jref$lc518406j_pfl.fits"), there are several points that should be borne in mind. The environment variable must be set in the Unix shell before logging into IRAF, and the directory name must include the trailing "/", e.g.:
setenv jref /data/cdbs7/jref/
Setting an IRAF environment variable jref will simply not work. If the reference files are in the default directory, jref can be set to ./ rather than editing the header to remove "jref$" from each of the reference file names. Furthermore, note that the file name is specified in the header using IRAF notation rather than Unix, i.e. "jref$lc518406j_pfl.fits" instead of "$jref/lc518406j_pfl.fits".
Input and output files to this task depend on which steps are set to PERFORM in the input parameter switches in the primary header of the input image under the section CALIBRATION SWITCHES. The acceptable input values for each switch are (PERFORM | OMIT | COMPLETE). COMPLETE has the same effect as OMIT. In the output image, those keywords which were set to PERFORM in the input image and for which processing was succesfully performed are set to COMPLETE.
1. To calibrate CCD observations in the association table with the rootname "j8aoa2010" when CRSPLIT = 2. This processing will include CCD processing with acsccd, cosmic-ray rejection with acsrej, and 2-D calibration of the cosmic-ray combined product with acs2d
In this case the reference files are in the directory "/data/cdbs7/jref/". Note that we must have assigned oref as an environment variable before starting the cl, and the value must include the trailing "/".
cl> show jref /data/cdbs7/jref/ cl> calacs j8aoa2010_asnThe ouput file will have the suffix _crj; specifically, "j8aoa2011_crj.fits".
2. Calibrate a single MAMA observation with the rootname j8a605amq.
cl> calacs j8a605amq_raw.fits
Task written by W. Hack based on CALSTIS routines written by P. Hodge, J.C. Hsu, and I. Busko.