You are here!

Official site of the design, build, test and launch of JWST.


Overview of the spacecraft, mission and science of JWST.

JWST related content on the NASA HOME PAGE plus links to NASA’s other great activities and missions.


JWST related Missions.


News, Careers, Locations & more.

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

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 will be 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. 

Instrument wavelength ranges

The FGS/NIRISS at NASA Goddard before integration into the instrument module.

Webb Telescope's Fine Guidance Sensor Gets Lots of Guidance

The integrated instrument module:

JWST Team Photo with Completed Flight Instrument module


FGS/NIRISS is being built by the Canadian Space Agency.

Links & Resources: