STIS Instrument Handbook for Cycle 24

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15.2	How Phase II Parameter Choices Affect Calibration

 

Table 15.1: Calibration Dependencies on Phase II Parameter Choices.

Parameter	Effect in pipeline calibration
Engineering MODE	Not calibrated; receive raw data files only.
Available-but-unsupported MODE	Calibrated through flat fielding only; no 2-D rectification, cosmic ray rejection (if applicable), flux calibration, or 1-D extraction.
MODE=ACQ or ACQ/PEAK	Not calibrated; receive raw data files only.
MODE=TIME-TAG	Data events are tabulated in rootname_tag.fits file with one binary table extension for each buffer read (determined by exposure time and BUFFER-TIME parameters). All raw data events are gathered into a single image, rootname_raw.fits, which is then passed through the normal calibration steps.
CCD only CR-SPLIT > 1 or Number_of_Iterations > 1	The number of imsets in the raw file equals CR-SPLIT or Number_of_Iterations. Raw file imsets are cosmic ray rejected and summed before the bias, dark, and flat-fielding corrections are made, producing a rootname_crj.fits file. The individual imsets are also flagged for cosmic rays and processed without summing to produce a rootname_flt.fits file.
MAMA only Number_of_Iterations > 1	The raw file contains Number_of_Iterations imsets, as do the flat-fielded and 2-D rectified files; the 1-D extracted files contain Number_of_Iterations tables. Repeat exposure imsets are summed after flat-fielding and 2-D rectification producing files rootname_sfl.fits and rootname_x2d.fits respectively (this is also true for imaging data). Note that for the MAMA detectors, 1-D spectral extraction data are not summed even when there are repeat exposures.
POS-TARG	Normal calibration processing.
PATTERN	Separate PATTERN step exposures are not associated with each other. Each PATTERN step exposure is processed through calibration independently.
WAVECAL=NO	No 1-D extraction or 2-D rectification of spectral data will be done, because the associated wavelengths would be incorrect and therefore misleading.
Target_Name=CCDFLAT	An internal STIS CCD flat-field lamp exposure useful in post-pipeline processing to correct for fringing above ~7000 е with gratings G750L and G750M.