Canada's NIRISS ready to see cosmos in over 2000 infrared colours
One of the James Webb Space Telescope's four primary scientific instruments known as the Near-Infrared Imager and Slitless Spectrograph (NIRISS), provided by the Canadian Space Agency, has concluded its post-launch preparations and is now ready for science.
The last NIRISS mode to be checked off before the instrument was declared ready to begin scientific operations was the single-object slitless spectroscopy (SOSS) capability. The heart of the SOSS mode is a specialized prism assembly that disperses the light of a star to create three distinctive spectra (rainbows), revealing the hues of more than 2000 infrared colours collected simultaneously in a single observation. This mode will be specifically used to probe the atmospheres of transiting exoplanets, i.e. planets that happen to eclipse their star periodically, dimming the star's brightness for a period of time. By comparing the spectra collected during and before or after a transit event with great precision, one can determine not only whether or not the exoplanet has an atmosphere, but also what atoms and molecules are in it.
With NIRISS post-launch commissioning activities concluded, the Webb team will continue to focus on checking off the five remaining modes on its other instruments. NASA's James Webb Space Telescope, a partnership with the European Space Agency and the Canadian Space Agency, will release its first full-colour images and spectroscopic data on .
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First images from the James Webb Space Telescope coming soon
The James Webb Space Telescope will release its first full-colour images and spectroscopic data on . The official release of images and data will showcase Webb's full science capabilities.
Deciding what Webb should look at first has been a project more than five years in the making, undertaken by an international partnership between NASA, ESA (European Space Agency), the Canadian Space Agency (CSA), and the Space Telescope Science Institute in Baltimore, home to Webb's science and mission operations.
Once each of Webb's instruments, including CSA's Near-Infrared Imager and Slitless Spectrograph (NIRISS), has been calibrated, tested, and given the green light by its science and engineering teams, the first images and spectroscopic observations will be made. These experts will proceed through a list of targets and then the production team will receive the data from Webb's instrument scientists and process it into images for astronomers and the public.
In addition to imagery, Webb will be capturing spectroscopic data – detailed information astronomers can read in light. The first images package of materials will highlight the science themes that inspired the mission and will be the focus of its work: the early universe, the evolution of galaxies through time, the lifecycle of stars, and other worlds. All of Webb's commissioning data – the data taken while aligning the telescope and preparing the instruments – will also be made publicly available.
After capturing its first images, Webb's scientific observations will begin. Canadian scientists will be some of the first to use the James Webb Space Telescope to make new discoveries about the universe. Teams have already applied through a competitive process for time to use the telescope, in what astronomers call its first "cycle," or first year of observations. These observations will mark the official beginning of Webb's general science operations.
The James Webb Space Telescope is the world's premier space science observatory. Webb will solve mysteries in our solar system, look beyond to distant worlds around other stars, and probe the mysterious structures and origins of our universe and our place in it. Webb is an international program led by NASA with its partners, ESA and the CSA.
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Webb Telescope in full focus, ready for instrument commissioning
Alignment of the James Webb Space Telescope is now complete. After full review, the observatory has been confirmed to be capable of capturing crisp, well-focused images with each of its four powerful onboard science instruments, including the Canadian Space Agency's NIRISS. Webb is ready to move forward into its next and final series of preparations, known as science instrument commissioning. This process of setting up and testing the instruments will take about two months before scientific operations begin in the summer.
The alignment of the telescope across all of Webb's instruments can be seen in a series of images that captures the observatory's full field of view.
Webb's mirrors are now directing fully focused light collected from space down into each instrument, and each instrument is successfully capturing images with the light being delivered to them. The image quality delivered to all instruments is as good as physically possible, given the size of the telescope.
Now, the Webb team will turn its attention to science instrument commissioning. Each instrument is a highly sophisticated set of detectors equipped with unique lenses, masks, filters, and customized equipment that helps it perform the science it was designed to achieve. The specialized characteristics of these instruments will be configured and operated in various combinations during the instrument commissioning phase to fully confirm their readiness for science.
As part of scientific instrument commissioning, the telescope will be commanded to point to different areas in the sky where the total amount of solar radiation hitting the observatory will vary to confirm thermal stability when changing targets. Furthermore, ongoing maintenance observations every two days will monitor the mirror alignment and, when needed, apply corrections to keep the mirrors in their aligned locations.
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Webb reaches alignment milestone, optics working successfully
On , assisted by the Canadian Space Agency's Fine Guidance Sensor, the Webb team completed the stage of mirror alignment known as "fine phasing." At this key stage in the commissioning of Webb's Optical Telescope Element, every optical parameter that has been checked and tested is performing at, or above, expectations. The observatory is able to successfully gather light from distant objects and deliver it to its instruments without issue.
Although there are months to go before Webb ultimately delivers its new view of the cosmos, achieving this milestone means the team is confident that Webb's first-of-its-kind optical system is working as well as possible.
With the fine phasing stage of telescope alignment completed, the team has now fully aligned Webb's primary imager, the Near-Infrared Camera, with the observatory's mirrors.
Over the next six weeks, the team will proceed through the next of several remaining alignment steps before final science instrument preparations. The team will further align the telescope to include the Near-Infrared Spectrograph, the Mid-Infrared Instrument, and the Canadian-built Near Infrared Imager and Slitless Spectrograph. In this phase of the process, an algorithm will evaluate the performance of each instrument and then calculate the final corrections needed to achieve a well-aligned telescope across all science instruments. Following this, Webb's final alignment step will begin, and the team will adjust any small, residual positioning errors in the mirror segments.
By late or early , the team is on track to conclude all aspects of Optical Telescope Element alignment and move on to approximately two months of science instrument preparations. Webb's first full-resolution imagery and science data will be released in early to mid-.
Webb is an international program led by NASA with its partners, the European Space Agency and the Canadian Space Agency. Webb's science operations are overseen for NASA by the Space Telescope Science Institute in Baltimore.
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Canada's FGS on Webb successfully used in mirror alignment phase
The Fine Guidance Sensor (FGS) on the James Webb Space Telescope, a mission-critical element designed and built in Canada, was used in tracking mode for the first time as part of the telescope's mirror alignment process.
On , the Webb team performed "Line of Sight" testing that confirmed the FGS's ability to "lock on" to a specific guide star in tracking mode. This mode allows the FGS to transmit highly precise information to Webb's positional system 16 times per second.
The successful FGS operation is the latest in a series of smooth manoeuvres for the massive observatory. After its launch on , the telescope underwent a delicate, month-long unfolding process as it travelled to its final destination, the second Lagrange point (L2).
Most recently, the team released an image mosaic of Webb seeing its first star: it shows 18 views of the same star – one for each of the 18 hexagonal segments that make up Webb's primary mirror.
In the coming weeks, with the help of the FGS, each mirror segment will be carefully adjusted to "stack" these views and calibrate the rest of the telescope's optical elements, to ultimately create a highly focused image of a single star.
The months-long mirror alignment process affords time for Webb's scientific instruments to shed heat. Because Webb will perform its observations in infrared light, its sensitive instruments, like Canada's NIRISS, must be extremely cold. They will gradually cool to an operating temperature of about -233 degrees Celsius.
Once the instruments have reached the correct temperature, Canada's FGS will be used throughout their commissioning, set to begin around the end of .
Photons received: Webb sees its first star – 18 times
The James Webb Space Telescope is nearing completion of the first phase of the months-long process of aligning the observatory's primary mirror using the Near Infrared Camera (NIRCam) instrument.
The team's challenge was twofold: confirm that NIRCam was ready to collect light from celestial objects, and then identify starlight from the same star in each of the 18 primary mirror segments. The result is an image mosaic of 18 randomly organized dots of starlight, the product of Webb's unaligned mirror segments all reflecting light from the same star back at Webb's secondary mirror and into NIRCam's detectors.
What looks like a simple image of blurry starlight now becomes the foundation to align and focus the telescope in order for Webb to deliver unprecedented views of the universe this summer. Over the next month or so, the team will gradually adjust the mirror segments until the 18 images become a single star.
During the image capturing process that began on , Webb was repointed to 156 different positions around the predicted location of the star and generated 1,560 images using NIRCam's 10 detectors, amounting to 54 gigabytes of raw data. The entire process lasted nearly 25 hours, but notably the observatory was able to locate the target star in each of its mirror segments within the first six hours and 16 exposures. These images were then stitched together to produce a single, large mosaic that captures the signature of each primary mirror segment in one frame. The images shown here are only a centre portion of that larger mosaic, a huge image with over 2 billion pixels.
Each unique dot visible in the image mosaic is the same star as imaged by each of Webb's 18 primary mirror segments, a treasure trove of detail that optics experts and engineers will use to align the entire telescope. This activity determined the post-deployment alignment positions of every mirror segment, which is the critical first step in bringing the entire observatory into a functional alignment for scientific operations.
NIRCam is the observatory's wavefront sensor and a key imager. It was intentionally selected to be used for Webb's initial alignment steps because it has a wide field of view and the unique capability to safely operate at higher temperatures than the other instruments. It is also packed with customized components that were designed to specifically aid in the process. NIRCam will be used throughout nearly the entire alignment of the telescope's mirrors. It is, however, important to note that NIRCam is operating far above its ideal temperature while capturing these initial engineering images, and visual artifacts can be seen in the mosaic. The impact of these artifacts will lessen significantly as Webb draws closer to its ideal cryogenic operating temperatures.
Moving forward, Webb's images will only become clearer, more detail-laden, and more intricate as its other three instruments arrive at their intended cryogenic operating temperatures and begin capturing data. The first scientific images are expected to be delivered to the world in the summer. Though this is a big moment, confirming that Webb is a functional telescope, there is much ahead to be done in the coming months to prepare the observatory for full scientific operations using all four of its instruments.
Abridged text is reprinted courtesy of NASA
Wakey wakey! Webb's instruments are on!
Now that Webb has reached its home orbit, 1.5 million kilometres away from Earth, the instruments have carefully been awoken. The telescope's four instruments and the Canadian Space Agency's (CSA's) Fine Guidance Sensor (FGS) were turned on one by one. Functionality checks will be performed over the coming days.
The FGS will play a crucial role in the alignment of Webb's 18 golden hexagonal mirrors, as the Optical Telescope Element begins its critical fine-tuning in space.
Over the course of the mission, the FGS will act as a stellar navigator, tracking bright stars to keep the telescope aligned, while NIRISS will be used to observe astronomical objects, such as exoplanets, brown dwarfs and rogue planets.
Launched , Webb will use infrared light to study the early universe and observe distant stars, exoplanet atmospheres, galaxy evolution, and much more. Canadian astronomers will be some of the first to use Webb's data and benefit from the tremendous science opportunities offered by this one-of-a-kind observatory.