Coding the JWST Calibration Pipeline(s) 2010 Calibration Workshop Robert Jedrzejewski/STScI

JWST Calibration Pipeline Plan STScI will develop the calibration pipelines for JWST SI Teams will provide the calibration algorithms to be used in the calibration pipelines Experience from developing the HST Calibration Pipelines will help guide the design

HST Calibration Pipelines CALCOS CALACS CALWF3 CALSTIS / acs/calacs/acsccd acsccd.c blevdrift.c blevfit.c doatod.c dobias.c doblev.c doccd.c doflash.c findblev.c findover.c getacsflag.c getccdsw.c mainccd.c /wf3/calwf3/wf3ccd blevdrift.c blevfit.c doatod.c dobias.c doblev.c doccd.c doflash.c findblev.c findover.c getccdsw.c getflags.c mainccd.c wf3ccd.c /stis/calstis/cs1 blevdrift.c blevfit.c doatod.c dobias.c doblev.c findblev.c findover.c getflags1.c

6 JWST Observing Modes JWST has 4 science instruments, each of which can be used in several ways for science NIRSpec Multi-Object Spectroscopy Long-slit spectroscopy Integral Field Spectroscopy MIRI Imaging Coronography Long-slit Spectroscopy Integral Field Spectroscopy FGS-TFI Imaging Coronography Non-redundant Mask Imaging NIRCam Imaging Coronography Grism Spectroscopy Instruments share several common modes!

7 Calibration flow All JWST data is a representation of a celestial scene, as processed by the OTE and instrument to create an image on the detector The detector turns that image into a digital dataset (imperfectly!) JWST OTE Instrument Detector Data Celestial Scene Image formed by telescope Image/spectrum formed by instrument Photons go this way

8 Decomposing the Calibration Pipeline Detector Calibration Instrument Calibration Imaging Calibration Spectroscopic Calibration Coronographic Calibration

9 Detector Calibration The detector calibration is simplified because we will only have 2 types of detectors on JWST 15 Hawaii 2RG HgCdTe detectors on NIRCam, NIRSpec, FGS/TFI 3 Si:As detectors on MIRI The description of the calibration steps will be the same for either detector type E.g., Both types of detectors have a Reference Pixel Correction step The best algorithm for doing the correction will often be different for different instruments It’s unlikely that the Reference Pixel Correction will be the same for Si:As and HgCdTe detectors And often the same The Nonlinearity Correction algorithm may well be the same for all detectors – we’ll see

JWST Calibration Pipelines or Pipeline? caljwst calDetector calNearIRDetectorcalMidIRDetector cal calImagingcalSpectroscopycalCoronography calInstrument

No more CALxxx Since we will develop the JWST calibration pipelines in parallel, we can share code much more easily The functionality shared among the instrument pipelines makes it advantageous to design modules that calibrate generic effects, rather than instrument-specific effects But the overall driver is the BEST calibration – we will not force the calibration steps to be the same for each instrument.

Summing Up We can take advantage of the fact that JWST instruments share identical detectors to have the calibration pipelines share much of the detector calibration code We can use the fact that several observing modes are shared by JWST instruments to have the calibration pipelines share significant amounts of instrument calibration code It makes more sense to think of CALJWST instead of CALSTIS/CALACS/CALNICA/CALWF3/CALCOS If a pipeline module needs to be different for different instruments, it will be