Stages of JWST Data Processing
The processing of JWST data goes through 3 stages. Stage 1 processes the raw data to produce count rate (slope) images. Stage 2 calibrates the slope images. Stage 3 carries out additional processing, including the ability to work with multiple exposures to create combined images and spectra..
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Science calibration pipeline stages
See also: JWST Data Calibration Considerations, Algorithm Documentation, Understanding JWST Data Files, JWST Science Calibration Pipeline Overview
Words in bold are GUI menus/
panels or data software packages;
bold italics are buttons in GUI
tools or package parameters.
- Stage 1: Apply detector-level corrections to the raw data for individual exposures and produce count rate (slope) images from the "ramps" of non-destructive readouts
- Stage 2: Apply physical corrections (e.g., slit loss) and calibrations (e.g., absolute fluxes and wavelengths) to individual exposures
- Stage 3: Combine the fully calibrated data from multiple exposures
Stage 1
This stage applies detector-level corrections to raw non-destructively read "ramps" in order to produce count rate images per exposure, or per integration for some modes.
- Input: raw ramps for all integrations
- Output: uncalibrated slope images for all integrations and exposures
- calwebb_detector1: applied for all data
Stage 2
See also: JWST Data Associations
This stage applies physical corrections and calibrations to individual exposures to produce fully calibrated (unrectified) exposures.
- input: uncalibrated slope images for all integrations and exposures
- output: calibrated slope images for all integrations and exposures
- calwebb_image2: applied to all imaging data (including coronagraphy and AMI)
- calwebb_spec2: applied to all spectroscopic data
Stage 3
See also: JWST Data Associations
This stage combines the fully calibrated data from multiple exposures.
- input: calibrated slope images for all integrations and exposures
- output: combined, rectified level-3 data
- calwebb_image3: applied to direct imaging data
- output: coadded image(s) (e.g., mosaic), catalog of sources, updated exposure level products
- calwebb_coron3: applied to coronagraphic data
- output: coadded image(s), and updated exposure level products
- calwebb_ami3: applied to NIRISS aperture masking interferometry data
- output: fringe parameters.
- calwebb_spec3: applied to spectroscopic data
- output: coadded spectral cube, extracted 1D spectrum, and updated exposure level products
- calwebb_tso3: applied to all time-series observations (photometry and spectroscopy)
- output: photometry and 1D spectroscopy for each integration and exposure, and updated exposure level products
Stages of processing by observation type
See also: JWST Observing Template
The full list of exposure type versus calibration pipeline stage is shown in the science calibration pipeline software documentation. Table 1 below shows the science calibration pipeline modules used to process the data from each JWST observing template.
Table 1. Science calibration pipeline modules vs. observing template
Pipeline module | Observing template |
---|---|
calwebb_detector1 | All |
calwebb_image2 | NIRCam Imaging NIRCam Coronagraphic Imaging NIRCam TSO Imaging NIRISS AMI NIRISS Imaging MIRI Imaging MIRI Coronagraphic Imaging All Target Acquisition Imaging FGS Science/Guide Imaging |
calwebb_spec2 | NIRCam WFSS NIRCam TSO Grism NIRSpec MOS NIRSpec FS spectroscopy NIRSpec IFU spectroscopy NIRSpec BOTS/TSO spectroscopy NIRISS SOSS NIRISS WFSS MIRI LRS MIRI MRS |
calwebb_image3 | NIRCam Imaging NIRISS Imaging MIRI Imaging |
calwebb_coron3 | NIRCam Coronagraphic Imaging MIRI Coronagraphic Imaging |
calwebb_ami3 | NIRISS AMI |
calwebb_sepc3 | NIRCam WFSS NIRSpec MOS NIRSpec FS Spectroscopy NIRSpec IFU Spectroscopy NIRISS WFSS MIRI LRS MIRI MRS |
calwebb_tso3 | NIRCam TSO Imaging NIRCam TSO Grism NIRSpec BOTS/TSO Spectroscopy NIRISS SOSS MIRI Imaging (TSO option) MIRI LRS (TSO option) MIRI MRS (TSO option) |