SPACE TELESCOPE SCIENCE INSTITUTE Operated for NASA by AURA COS Pipeline Calibration Outline of CALCOS Processing Steps and Keywords Reference Files Associations Reuse of CALSTIS Code Retain CALSTIS nomenclature and file naming conventions to the extent that it is useful to do so.

COS PIPELINE PDR P. Hodge December 7, 2000CALCOS Space Telescope Science Institute 2 of 13 Outline of CALCOS Calibrate each wavecal file:Calibrate each wavecal file: Apply the same calibration as for science data Apply the same calibration as for science data Extract 1-D spectrum Extract 1-D spectrum Determine offset in dispersion direction Determine offset in dispersion direction If data are in TIMETAG mode:If data are in TIMETAG mode: If FUV, determine locations and count rates of stim pins If FUV, determine locations and count rates of stim pins Create corrected timetag table Create corrected timetag table Create accum image from timetag table Create accum image from timetag table Process ACCUM data:Process ACCUM data: Basic 2-D calibration (unless already done) Basic 2-D calibration (unless already done) Extract 1-D spectrum Extract 1-D spectrum Apply wavelength zero point offset from wavecal Apply wavelength zero point offset from wavecal

COS PIPELINE PDR P. Hodge December 7, 2000CALCOS Space Telescope Science Institute 3 of 13 FUV Reduction Process Input Files Processing Step Keyword Switch Output File _rtg or _raw DQITAB Assign data quality DQICORR _ctg or _flt BRFTAB Thermal distortion correction TEMPCORR _ctg or _flt GEOTAB Geometric (INL) correction GEOCORR _ctg or _flt Livetime correction LIVECORR _ctg or _flt PFLTFILELFLTFILE Divide by flat field FLATCORR _ctg or _flt

COS PIPELINE PDR P. Hodge December 7, 2000CALCOS Space Telescope Science Institute 4 of 13 FUV Reduction Process (cont.) Input Files Processing Step Keyword Switch Output File Orbital Doppler correction DOPPCORR _ctg or _flt Heliocentric Doppler correction HELCORR _ctg or _flt PHATAB Filter by pulse height (or verify good pulse height) PHACORR _ctg or _flt BADTTAB Filter by time BADTCORR_ctg _ctg Bin timetag into 2-D accum image BINCORR_flt

COS PIPELINE PDR P. Hodge December 7, 2000CALCOS Space Telescope Science Institute 5 of 13 FUV Reduction Process (cont.) Input Files Processing Step Keyword Switch Output File _fltXTRACTAB Extract 1-D spectrum X1DCORR_x1d _flt Subtract background BACKCORR_x1d LAMPTAB Correct wavelength zero point WAVECORR_x1d _x1dDISPTAB Assign wavelengths DISPCORR_x1d _x1dPHOTTAB Convert count rate to flux FLUXCORR_x1d _x1d Combine FP-split data FPCORR_x1s

COS PIPELINE PDR P. Hodge December 7, 2000CALCOS Space Telescope Science Institute 6 of 13 NUV Reduction Process Input Files Processing Step Keyword Switch Output File _rtg or _raw DQITAB Assign data quality DQICORR _ctg or _flt Livetime correction LIVECORR _ctg or _flt PFLTFILELFLTFILE Divide by flat field FLATCORR _ctg or _flt Orbital Doppler correction DOPPCORR _ctg or _flt Heliocentric Doppler correction HELCORR _ctg or _flt

COS PIPELINE PDR P. Hodge December 7, 2000CALCOS Space Telescope Science Institute 7 of 13 NUV Reduction Process (cont.) Input Files Processing Step BADTTAB Filter by time BADTCORR_ctg _ctg Bin timetag into 2-D accum image BINCORR_flt _fltXTRACTAB Extract 1-D spectrum X1DCORR_x1d _flt Subtract background BACKCORR_x1d LAMPTAB Correct wavelength zero point WAVECORR_x1d _x1dDISPTAB Assign wavelengths DISPCORR_x1d _x1dPHOTTAB Convert count rate to flux FLUXCORR_x1d

COS PIPELINE PDR P. Hodge December 7, 2000CALCOS Space Telescope Science Institute 8 of 13 Reference Images Table Name SuffixDescription Selection Criteria PFLTFILEpfl Pixel-to-pixel flat field DETECTOR LFLTFILElfl Low-order flat field DETECTOR

COS PIPELINE PDR P. Hodge December 7, 2000CALCOS Space Telescope Science Institute 9 of 13 Reference Tables Table name SuffixDescription Selection keywords Selection columns Parameter columns DQITABbpx Locations of bad pixels DETECTORSEGMENT lx, ly, dx, dy, q, type BADTTABtim Bad time intervals start, stop BRFTABbrf Baseline reference frame parameters DETECTORSEGMENT sx1, sy1, sx2, sy2 PHATABpha Pulse height thresholds DETECTORSEGMENT llt, ult

COS PIPELINE PDR P. Hodge December 7, 2000CALCOS Space Telescope Science Institute 10 of 13 Reference Tables (cont.) Table name SuffixDescription Selection keywords Selection columns Parameter columns GEOTABgeo Geometric (INL) correction DETECTORSEGMENT xnelem, xdispl*, ynelem, ydispl* XTRACTAB1dx Locations of spectra and background regions DETECTOR SEGMENT, OPT_ELEM, CENWAVE slope, b_spec, (or b_a, b_b, b_c), bkg1, bkg2, height, bheight, bwidth

COS PIPELINE PDR P. Hodge December 7, 2000CALCOS Space Telescope Science Institute 11 of 13 Reference Tables (cont.) Table name SuffixDescription Selection keywords Selection columns Parameter columns LAMPTABlmp Template lamp spectrum nelem, wavelength*, flux* DISPTABdsp Dispersion coefficients DETECTOR SEGMENT, OPT_ELEM, CENWAVE ncoeff,coeff* PHOTTABpht Photometric throughput DETECTOR SEGMENT, APERTURE, OPT_ELEM, CENWAVE nelem, wavelength*, throughput*

COS PIPELINE PDR P. Hodge December 7, 2000CALCOS Space Telescope Science Institute 12 of 13 Associations CALCOS uses the association table to identify files that will be used in calibrationCALCOS uses the association table to identify files that will be used in calibration Contents of an association:Contents of an association: science data science data wavecal data wavecal data Science data:Science data: timetag timetag accum: accum: spectrum spectrum stim-pulse data (FUV) stim-pulse data (FUV) pulse-height data (FUV) pulse-height data (FUV) both FUV segments in the same file both FUV segments in the same file FP-split or repeatobs in separate files FP-split or repeatobs in separate files

COS PIPELINE PDR P. Hodge December 7, 2000CALCOS Space Telescope Science Institute 13 of 13 Reuse of CALSTIS Code Algorithm reuse, more than code reuse:Algorithm reuse, more than code reuse: Estimate of code reuse: 5%Estimate of code reuse: 5% Estimate of algorithm reuse: 30%Estimate of algorithm reuse: 30% Differences that affect the code but not necessarily the algorithm:Differences that affect the code but not necessarily the algorithm: Wavecal observations will be handled differentlyWavecal observations will be handled differently Different zero point for on-board Doppler shift (affects convolution of flat fields)Different zero point for on-board Doppler shift (affects convolution of flat fields) NUV spectra arranged differently on detectorNUV spectra arranged differently on detector