NASA's James Webb Space Telescope


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Near-Infrared Imager and Slitless Spectrograph (NIRISS)

The JWST Near-Infrared Imager and Slitless Spectrograph (NIRISS) provides unique observational capabilities between 0.6 and 5 microns that complement those available with NIRCam and NIRSpec. Its efficient, all-reflective design enables low-resolution, wide-field grism spectroscopy; medium-resolution grism spectroscopy optimized for applications  requiring extreme spectrophotometric stability; aperture masking interferometry; and parallel imaging through filters matched to those available with NIRCam. 

  For detailed instrument information, please consult the NIRISS JWST User Documentation (JDox). 

NIRISS is a contribution of the Canadian Space Agency to the JWST project.  Honeywell International designed and built the instrument in collaboration with a team lead by the Principal Investigator, René Doyon of the Université de Montréal. Additional technical support was provided by the National Research Council of Canada’s Herzberg Astronomy and Astrophysics Research Centre.

Illustration showing various simulated NIRISS images.
NIRISS Wide-Field Slitless Spectroscopy simulations of the gravitationally lensed cluster MACS J0416.1-2403.  Left:  Image through the F200W filter.  Middle and right: Slitless spectra through the F200W filter with the GR150R grism and the GR150C grism.  Observations with orthogonal dispersion directions can be used to disentangle blended spectra in crowded fields.