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James modes

The James Webb instruments are used to study the universe.

With the James Webb Space Telescope now fully aligned and capturing crisp images, the team has moved on to getting its instruments calibrated. While this process is ongoing, NASA has shared an update about the 17 different modes that will be possible using Webb’s four instruments, with examples of what kind of scientific research will…


With the James Webb Space Telescope fully aligned , and taking crisp images, the team is now working to calibrate its instruments. While this process is ongoing, NASA has shared an update about the 17 different modes that will be possible using Webb’s four instruments, with examples of what kind of scientific research will be possible with each.

As the engineers work on calibrating Webb’s instruments, they will check through each of the 17 modes and make sure it is ready for science operations to begin this summer.

Near-Infrared Camera (NIRCam) modes:

  1. Imaging. Webb will use this instrument to take pictures in the near-infrared wavelength. It will take pictures of individual galaxies as well as deep fields such the Hubble Ultra-Deep Field.
  2. Wide field slitless spectroscopy. This mode in which light is divided into different wavelengths was initially intended for alignment of the telescope. However, scientists discovered that they could use it for science-related tasks, such as observing distant quarks.
  3. Coronagraphy. Stars are a source of light that is very bright. The glare from stars can obscure fainter sources. This mode uses a disk to block bright light sources so that dimmer objects, such as exoplanets orbiting around bright star clusters, can be seen.
  4. Time series observations – imaging. This mode can be used to observe objects changing quickly, such as magnetars.
  5. Time series observations – grism. This mode can be used to look at the light passing through the atmosphere on exoplanets in order to find out what it is made of.

Near-Infrared Spectrograph (NIRSpec) modes:

  1. Multi-object spectroscopy. The instrument has a microshutter array that allows thousands of windows to be individually opened and closed. Each window is approximately the same width as a human hair. This allows the instrument to observe up to 100 objects at the same time, meaning it can collect data far faster than previous instruments. It can capture deep field images, such as one from the Extended Groth Strip.
  2. Fixed slit spectroscopy. This mode is not able to look at multiple targets simultaneously. Instead, it uses fixed slits that allow for sensitive readings of individual targets. For example, looking at light coming from gravitational waves known as kilonovas.
  3. Integral field unit spectroscopy. This mode is able to see light from a smaller area than a single point. It allows researchers to look at distant galaxies and other objects that appear larger because of an effect called gravitational lensesing.
  4. Bright object time series. This mode allows researchers the ability to examine objects that change rapidly over time. For example, an exoplanet orbiting its star in full orbit.

Near-Infrared Imager and Slitless Spectrograph (NIRISS) modes:

  1. Single object slitless spectroscopy. This mode blocks out the light from bright objects to allow researchers to see smaller objects such as rocky Earth-like plants found in the TRAPPIST systems.
  2. Wide field slitless spectroscopy. This type of spectroscopy can be used to view the farthest galaxies.
  3. Aperture masking interferometry. This mode blocks out light from some of the 18 segments of Webb’s primary mirror to allow high-contrast imaging, like looking at a binary star system where stellar winds from each star are colliding.
  4. Imaging. This mode can be used as a backup to the NIRCam imaging and can be used even if the other instruments are in use. It can be used to image targets such as a gravitationally lensing cluster of galaxy clusters.

Mid-Infrared Instrument (MIRI) modes:

  1. Imaging. MIRI works in the mid-infrared wavelength, which is useful for looking at features like dust and col

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