Imaging Roadmap

A roadmap to guide users, step-by-step, through the process of designing a JWST imaging observing program using NIRCam or MIRI.

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Main article:  JWST Imaging

Each step listed below is followed by a list of articles with additional details. 

Preliminary considerations

Note: NIRISS imaging is only offered for coordinated parallel observations. For this reason NIRISS links below are shown in parentheses.

  1. Choose the instrument(s) suitable for your science based on needed wavelength coverage. NIRISS imaging may be obtained in parallel with NIRCam, offering sensitivity and wavelengths similar to NIRCam and extending the spatial coverage to a nearby area.

    NIRCam Imaging (0.6–5.0 μm), NIRCam Imaging Recommended Strategies
    MIRI Imaging (5.6–25.5 μm), MIRI Imaging Recommended Strategies
    (NIRISS Imaging (0.8–5.0 μm), NIRISS Imaging Recommended Strategies)

  2. Decide on whether you will observe with multiple instruments simultaneously.
    Coordinated Parallel Observations

  3. Consider using the quick-look JWST Interactive Sensitivity Tool (JIST) to obtain a sense of the signal-to-noise and exposure time parameter space you may require for your target(s).

    Work through the steps below for the primary imaging instrument before adding the coordinated parallel observations, which may be imaging or some other allowed mode.

For each instrument you will use for standard imaging, proceed through the steps below.

Standard imaging

  1. Check the feasibility of your observations to achieve your science goals.
    NIRCam Imaging Sensitivity
    MIRI Sensitivity
    (NIRISS Imaging Sensitivity)

  2. Select your wavelength coverage and filters.
    NIRCam Filters
    MIRI Filters and Dispersers
    (NIRISS Filters)

  3. Consider the areal coverage needed and whether mosaicking of the instrument field of view will be needed.
    NIRCam Mosaics
    MIRI Imaging Mosaics
    APT Simple Mosaic Example
    Use the Aladin viewer in APT to view instrument fields of view on sky images.

  4. Based on the brightness of your target, determine whether a subarray is needed to avoid saturation. (Subarrays are not offered for the NIRISS imaging mode.)
    NIRCam Bright Source LimitsNIRCam Detector Subarrays
    MIRI Bright Source LimitsMIRI Detector Subarrays

  5. Select a dithering strategy.

    NIRCam Dithers and Mosaics
    MIRI Dithering
    If proposing coordinated parallel observations, consider: 
    JWST Coordinated Parallels Custom Dithers

  6. For selected instrument(s), calculate the required exposure times using the JWST Exposure Time Calculator (ETC).

    JWST ETC Imaging Aperture Photometry Strategy

  7. Fill out the Astronomers Proposal Tool (APT) for your observations.
    NIRCam Imaging APT Template
    MIRI Imaging APT Template
    (NIRISS Imaging APT Template)

  8. If adding coordinated parallel observations, now is the time to do that.  See the separate Roadmap for coordinated parallels

Go to the Getting Started with JWST Proposing to complete the steps for proposal submission.

Latest updates

    Reviewed and updated for Cycle 1 release.

Originally published