FGS is a "guider," which helps point the telescope. NIRISS is used to investigate the following science objectives: first light detection, exoplanet detection and characterization, and exoplanet transit spectroscopy.

INSTRUMENTS

FGS/NIRISS

Fine Guidance Sensor /
Near InfraRed Imager and Slitless Spectrograph (FGS/NIRISS)

Webb Telescope's Fine Guidance Sensor Gets Lots of Guidance
The FGS/NIRISS at NASA Goddard before integration into the instrument module.
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Range

Instrument wavelength ranges

FGS/NIRISS operates over a wavelength range of 0.8 to 5.0 microns

The Fine Guidance Sensor (FGS) allows Webb to point precisely, so that it can obtain high-quality images. The Near Infrared Imager and Slitless Spectrograph part of the FGS/NIRISS is used to investigate the following science objectives: first light detection, exoplanet detection and characterization, and exoplanet transit spectroscopy.

FGS/NIRISS has a wavelength range of 0.8 to 5.0 microns, and is a specialized instrument with three main modes, each of which addresses a separate wavelength range. FGS is a "guider," which helps point the telescope. 

Video: FGS/NIRISS 3d Diagram Rotation

JWST Team Photo with Completed Flight Instrument module
JWST Team Photo with Completed Flight Instrument module
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fgs engineering diagram
FGS/NIRISS was built by the Canadian Space Agency.

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