instrument

nirspec

The Near-Infrared Spectrograph on the James Webb Space Telescope, used for spectroscopy of astronomical objects.
51 related articles

Description

The Near-Infrared Spectrograph (NIRSpec) is one of the four main instruments aboard the James Webb Space Telescope (JWST). It is designed to split incoming infrared light into its component wavelengths, revealing the chemical composition, temperature, and motion of distant astronomical objects. NIRSpec operates in the near-infrared range (0.6 to 5 microns), a part of the spectrum where many key molecules and elements have distinctive spectral fingerprints, and where light from the most distant galaxies is redshifted into view.

History

NIRSpec was built by the European Space Agency (ESA) with contributions from NASA and other partners. It was launched aboard JWST in December 2021 and became operational in 2022. The concept of a multi-object near-infrared spectrograph for a space telescope dates back to the early planning stages of JWST in the 1990s.

How it works

NIRSpec uses a micro-shutter array—a grid of tiny, individually controllable doors—to block out unwanted light from bright sources while letting light from up to hundreds of faint targets pass through simultaneously. The light then travels through a dispersing element (a grating or prism) that spreads it into a spectrum, which is recorded by a detector. This allows astronomers to obtain spectra of many objects at once, a major advantage for surveying large numbers of galaxies or stars.

In practice

NIRSpec is used to study the atmospheres of exoplanets, the composition of interstellar clouds, the properties of the earliest galaxies, and the remnants of supernovae, among many other targets.

Fun fact

NIRSpec's micro-shutter array contains over 62,000 individual shutters, each about the width of a human hair, that can be opened or closed independently to select targets.

Concept graph →

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