Uploaded September 2021 | Updated September 2026, 5 hours ago
The NIRSpec instrument is the workhorse near-infrared spectrograph on board the James Webb Space Telescope and is provided by ESA.
NIRSpec can make spectroscopic observations of complex targets in space, such as galaxies, nebulae, or crowded fields of stars or galaxies, in one single shot.
One technology it uses is that of ‘integral field units’ (IFUs). Here, an image-slicing technique is used to reorganise the signal from a two-dimensional image of the sky into a set of slices.
These slices are fed to a spectrograph that generates a spectrum for each pixel, where the light is split into its different wavelengths. The slices are then arranged into a data cube. This cube is a stack of many images of the same target object in space, each at a different wavelength, and provides a comprehensive overview of the whole object under study.
This animation shows the path followed by light from an astronomical object as it travels through the NIRSpec components and onto the detector.
~ 0:22 min: The light from the telescope enters NIRSpec via the Pick-off Mirror
~ 0.27 min: The second flat mirror directs the beam towards the FORE optics that form an image of the sky onto the Micro Shutter Assembly (MSA).
~ 0:36 min: The light passes through a Filter Wheel Assembly (FWA) for selecting specific wavelength bands and through the refocusing mechanism (RMA).
~ 0:42 min: A sharp image of the sky is formed onto the MSA.
~ 0:49 min: With MSA shutters all closed a small portion of light passes through the now open IFU entrance aperture.
~ 0:52 min: Two small flat mirrors and two powered mirrors form a magnified image of the IFU field of view onto the “slicer” mirror.
~ 1.01 min: The slicer mirror creates 30 new beams, each for a specific fraction of the IFU field of view.
~ 1:05 min: 30 individual beams exit the IFU and enter the NIRSpec spectrometer optics.
~ 1:12 min: The collimator optics brings the beam to the Grating Wheel Assembly (GWA).
~ 1:15 min: The Grating or Prism unravels the incoming beam in all its wavelengths by dispersing it vertically.
~ 1:18 min: The Camera optical system forms 30 spectra (one for each individual IFU beam) onto the detector.
Spaxel: Spatial Element (as opposed to a pixel which is a picture element). Is one 3D element of the IFU cube (x, y, wavelength). It is a spectrum at a certain point of the IFU image.
Counts: The count of photons that were received by the detector for this specific wavelength.
NIRSpec will allow scientists to study objects embedded in shrouds of gas and dust, to find out more about how galaxies formed and evolved, and to characterize the atmospheres of extrasolar planets to determine if water is present.
Source: https://www.esa.int/ESA_Multimedia/Videos/2021/09/Webb_NIRSpec_integral_field_units_principle_animation
The NIRSpec instrument is the workhorse near-infrared spectrograph on board the James Webb Space Telescope and is provided by ESA.
NIRSpec can make spectroscopic observations of complex targets in space, such as galaxies, nebulae, or crowded fields of stars or galaxies, in one single shot.
One technology it uses is that of ‘integral field units’ (IFUs). Here, an image-slicing technique is used to reorganise the signal from a two-dimensional image of the sky into a set of slices.
These slices are fed to a spectrograph that generates a spectrum for each pixel, where the light is split into its different wavelengths. The slices are then arranged into a data cube. This cube is a stack of many images of the same target object in space, each at a different wavelength, and provides a comprehensive overview of the whole object under study.
This animation shows the path followed by light from an astronomical object as it travels through the NIRSpec components and onto the detector.
~ 0:22 min: The light from the telescope enters NIRSpec via the Pick-off Mirror
~ 0.27 min: The second flat mirror directs the beam towards the FORE optics that form an image of the sky onto the Micro Shutter Assembly (MSA).
~ 0:36 min: The light passes through a Filter Wheel Assembly (FWA) for selecting specific wavelength bands and through the refocusing mechanism (RMA).
~ 0:42 min: A sharp image of the sky is formed onto the MSA.
~ 0:49 min: With MSA shutters all closed a small portion of light passes through the now open IFU entrance aperture.
~ 0:52 min: Two small flat mirrors and two powered mirrors form a magnified image of the IFU field of view onto the “slicer” mirror.
~ 1.01 min: The slicer mirror creates 30 new beams, each for a specific fraction of the IFU field of view.
~ 1:05 min: 30 individual beams exit the IFU and enter the NIRSpec spectrometer optics.
~ 1:12 min: The collimator optics brings the beam to the Grating Wheel Assembly (GWA).
~ 1:15 min: The Grating or Prism unravels the incoming beam in all its wavelengths by dispersing it vertically.
~ 1:18 min: The Camera optical system forms 30 spectra (one for each individual IFU beam) onto the detector.
Spaxel: Spatial Element (as opposed to a pixel which is a picture element). Is one 3D element of the IFU cube (x, y, wavelength). It is a spectrum at a certain point of the IFU image.
Counts: The count of photons that were received by the detector for this specific wavelength.
NIRSpec will allow scientists to study objects embedded in shrouds of gas and dust, to find out more about how galaxies formed and evolved, and to characterize the atmospheres of extrasolar planets to determine if water is present.
Source: https://www.esa.int/ESA_Multimedia/Videos/2021/09/Webb_NIRSpec_integral_field_units_principle_animation
![Gale Crater - Mars Science Laboratory (MSL) Curiosity Rover Landing Site [HD]](https://i.ytimg.com/vi/w5DK3SxolJI/mqdefault.jpg "Gale Crater - Mars Science Laboratory (MSL) Curiosity Rover Landing Site [HD]
...http://www.telescopefeed.com/
A birds-eye view of Curiositys landing site: Mars Gale Crater.
Transcript: John Grotzinger: Im John Grotzinger, the project scientist for Mars Science Laboratory the Curiosity rover and were going to take Curiosity to our chosen landing site in Gale crater, which sits at the border between the southern highlands of Mars and the northern lowlands, a really exciting spot because its very low and thats the kind of place where water might have pooled and possibly formed lakes.
So here we see a different view of Gale crater that has a different perspective. You can see our landing ellipse down at the bottom, which is the white circle. And in the middle of Gale crater is this mountain of rock that is 5 kilometers high, made layer by layer by layer. But the layers at the bottom are the ones that were most interested in, because we think that those were deposited in an aqueous environment, which is very important for understanding habitability. What you can see here now is that were about to land very close to the center of the landing ellipse, and we have a couple of different routes that we can take. The scientists on the team prefer the one on the right. And so what we would do is drive along it.
And now you can see at the base of this mountain where these lower layers are. And the layers are important because they allow us to sort of read a geological book. You start at the bottom of the mountain and those are the oldest layers. And then the layers that occur up near the top, those are the youngest parts, the youngest chapters in the book.
We will drive along, up to this outcrop that we call the fence. And when we get there, were going to study it. Its a really attractive spot for us because it contains the kind of minerals that formed in water. And then, when were done with that, were going to go beyond. And were going to enter a canyon. And this kind of terrain around here reminds us a lot of Sedona, Arizona. And all the rocks around here formed in aqueous environments. And so, theres a lot of rock, hundreds of meters of it, layer after layer, that we can study to tell us about the history of Mars at Gale crater.
Now we cross a boundary and we go into a very different type of rock. You can see how it weathers very differently. Its really rugged. So at that point in the mission, well be beyond our initial mission of two Earth years. This will take us into many years afterwards of exploration as we drive around this very rugged terrain. If we make it, well be able to look back over the area that we have previously studied, back down in towards the bottom of Gale crater, back towards our landing ellipse.
Source: http://www.nasa.gov/multimedia/videogallery/index.html?media_id=102633381")
