JWST Imaging

Several JWST instruments have imaging capabilities, covering different fields of view and wavelengths.

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Standard imaging

Main articles: MIRI Imaging, NIRCam Imaging, NIRISS Imaging
See also: JWST Mosaic OverviewJWST Dithering Overview

MIRI, NIRCam, and NIRISS are the imaging instruments on JWST. The wavelength ranges and available modes of use are summarized in Table 1. The "main article" links above connect you to the details for each instrument. Note that NIRISS imaging is only offered as a parallel observing mode. 

In addition:


Table 1. Summary of JWST's standard imaging capabilities

InstrumentWavelength rangeMode of use
NIRCam0.6 μm < λ < 5 μm Primary or parallel
MIRI5.6 μm < λ < 25.5 μm Primary or parallel
NIRISS0.8 μm < λ < 5 μm Parallel only


NIRCam provides imaging in 2 wavelength ranges simultaneously over the same 9.7 arcmin² field of view (via a dichroic): 0.6–2.3 μm (0.031"/pix) and 2.4–5.0 μm (0.063"/pix). It uses 2 near-identical side-by-side modules, separated by a 44" gap. NIRCam's short wavelength channel also has small 4"–5" gaps between detectors. 

MIRI offers imaging at a complementary wavelength range, from 5.6 to 25.5 μm over a 3.1 arcmin² field of view, and has a detector plate scale of 0.11"/pixel.

NIRISS offers 0.8–5.0 μm (0.065"/pix) imaging in a 4.84 arcmin² field of view and many of its filters are essentially identical counterparts to the NIRCam filters. Consequently, NIRCam and NIRISS can be used in parallel to increase the sky coverage at a particular wavelength. NIRISS imaging is not offered as a primary mode.

All the standard imaging modes offer a mosaicking capability for observing larger areas.  Dithering is also recommended for imaging to improve data quality.



Overview figures

Figure 1 shows the relative positions of the imager fields of view within the JWST focal plane, which is useful to know when planning parallel observations.

Figure 1. Imager fields of view in the JWST focal plane

The 3 imaging instruments (NIRCam, NIRISS, and MIRI) are highlighted here in the JWST focal plane. FGS indicates the Fine Guidance Sensor fields of view, used for guiding.
Figure 2 highlights the relative wavelength ranges for the imaging instruments on JWST.  JWST time-series observations (TSO) and high-contrast imaging (HCI) also use the imagers and are shown for completeness.  However, they involve specialized operations that are described elsewhere in JDox.
Figure 2. Summary of JWST's imaging capabilitities

Wavelength coverage of each instrument, highlighting different imaging capabilities. Note that standard imaging with NIRISS is allowed in parallel mode only.



Published

 

Latest updates

  • Updated links, including to the new imaging Roadmap article. Simplified and clarified text.