James Webb Space Telescope (JWST)

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neufer
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Re: James Webb Space Telescope is now fully deployed

Post by neufer » Mon Jan 10, 2022 7:20 pm

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Kevin_Hall wrote: Mon Jan 10, 2022 5:18 pm
The Webb Space Telescope has transormned into its final form. Now it is on its way to Lagrange point 2.
JWST has already completed about 80% of the way.

https://twitter.com/NASAWebb/status/147 ... 60609?s=20

Just a quick reminder: the main goal of James Webb Space Telescope is discovering the birth of stars and galaxies, looking for planets to live on. This is the greatest telescope we have ever created.
That's quite a statement in behalf of a telescope that's still half a year away from first light.
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Re: James Webb Space Telescope (JWST)

Post by Kevin_Hall » Thu Jan 13, 2022 11:18 am

JWST has started the alignment of its 18 golden hexagons. When the setting finishes, the mirrors will be workning as a single focusing instrument.
Whole procedure will take 3 months.
By the way, JWST has already completed 84% of its way to Lagrange point 2. I've also found a cool explanation of JWST by Tyson, highly recommend you to watch it.
https://www.youtube.com/watch?v=ULxl7pfeUL4

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Re: James Webb Space Telescope (JWST)

Post by neufer » Sun Jan 16, 2022 4:47 pm

  • Half an inch, half an inch,
    Half an inch onward,
    All into the valley of L2
    Rode the JWST.
https://www.jwst.nasa.gov/content/webbLaunch/whereIsWebb.html?units=metric wrote:
Mirror Segment Deployment Tracker

<<This image tracks the progress of the individual primary mirror segments (A,B,C) and the secondary (SM) mirror as they move upward 12.5mm from their stowed launch position to a deployed state where they are ready for the mirror alignment process. The mirrors move in very small increments over the course of ~10 days to complete their deployment. They move approximately 1mm per day each. For more detail on this process read this blog entry. Each primary mirror segment has an ID which consists of a letter (A,B,C) followed by a number. The letter denotes one of 3 different 'prescriptions' for each group of primary mirror segments. NOTE: Segment A3 and A6 are being moved separately at the end of the process because their position sensors are read out in a different way.>>
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Re: James Webb Space Telescope (JWST)

Post by neufer » Wed Jan 19, 2022 11:44 pm

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Re: James Webb Space Telescope (JWST)

Post by orin stepanek » Thu Jan 20, 2022 2:42 am

neufer wrote: Wed Jan 19, 2022 11:44 pm
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Thanks Art! 8-)
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Re: James Webb Space Telescope (JWST)

Post by neufer » Mon Jan 24, 2022 1:43 pm

https://www.youtube.com/watch?v=pWklR2PBfQU wrote:
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NASA Science Live:Scheduled for 3:00 PM Jan 24, 2022
What’s Next for the James Webb Space Telescope?


<<The past month has been an exciting one for NASA’s James Webb Space Telescope — from launch in tropical French Guiana, to the two-week unfolding of this intricately-packed telescope, the observatory has gone through a huge transformation in space. What’s next for Webb as it cools down over the next five months and looks to #UnfoldTheUniverse?>>
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Re: James Webb Space Telescope (JWST)

Post by neufer » Fri Jan 28, 2022 2:21 pm

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Re: James Webb Space Telescope (JWST)

Post by neufer » Thu Feb 10, 2022 7:26 pm

https://www.nasa.gov/press-release/nasa-to-discuss-webb-telescope-progress-mirror-alignment wrote:
<<NASA will hold a media teleconference at 11 a.m. EST on Friday, Feb. 11, to share progress made in the early stages of aligning the James Webb Space Telescope’s mirrors. The agency will livestream audio of the teleconference on its website.

Engineers and scientists will review the first weeks of the months-long alignment process and discuss early imagery that shows how the Webb team has identified starlight through each of telescope’s 18 hexagonal mirror segments. NASA will make this imagery available at 10:30 a.m. before the call on the Webb telescope blog.

Teleconference participants include:
  • Lee Feinberg, Webb optical telescope element manager, NASA’s Goddard Space Flight Center in Greenbelt, Maryland
    Marshall Perrin, Webb deputy telescope scientist, Space Telescope Science Institute in Baltimore
    Marcia Rieke, principal investigator for the NIRCam instrument and regents professor of astronomy, University of Arizona in Tucson
The Webb team has begun to fine-tune the telescope using images captured by its Near-Infrared Camera (NIRCam). The early engineering imagery produced during this stage in the process, called “segment image identification,” stitches together more than 1,000 images to form 18 unfocused versions of a single star. This serves as the starting point for gradually aligning Webb’s mirror segments into one precise system.

Following the telescope’s alignment over the next several months, the Webb team will then move on to prepare the instruments for science observations and release the mission's first science images and data in the summer.>>
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Webb Sees Its First Star – 18 Times

Post by bystander » Sun Feb 13, 2022 3:41 pm

Webb Sees Its First Star – 18 Times
NASA | JWST | 2022 Feb 11
Click to view full size image 1 or image 2
This image mosaic was created by pointing the telescope at a bright, isolated star in the
constellation Ursa Major known as HD 84406. This star was chosen specifically because it
is easily identifiable and not crowded by other stars of similar brightness, which helps to
reduce background confusion. Each dot within the mosaic is labeled by the corresponding
primary mirror segment that captured it. These initial results closely match expectations
and simulations. Credit: NASA

Click to play embedded YouTube video.
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 Feb. 2, 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 notedly 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 center 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. ...
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Re: Webb Sees Its First Star – 18 Times

Post by neufer » Sun Feb 13, 2022 4:49 pm

https://en.wikipedia.org/wiki/18_(number) wrote:
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<<There are 18 holes on a regulation golf course.

The Hebrew word for "life" is חי (chai), which has a numerical value of 18. Consequently, the custom has arisen in Jewish circles to give donations and monetary gifts in multiples of 18 as an expression of blessing for long life.

Joseph Heller's novel Catch-22 was originally named Catch-18 because of the Hebrew meaning of the number, but was amended to the published title to avoid confusion with another war novel, Mila 18.

There are 18 chapters in the Bhagavad Gita, which is contained in the Mahabharata, which has 18 books. The Kurukshetra War which the epic depicts, is between 18 armies. The war itself lasts for 18 days. In the other Hindu epic, the Ramayana, the war between Rama and the demons also lasted 18 days.>>
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Webb Team Brings 18 Dots of Starlight into Hexagonal Formation

Post by bystander » Sun Feb 20, 2022 3:01 pm

Webb Team Brings 18 Dots of Starlight into Hexagonal Formation
NASA | JWST | 2022 Feb 19
Click to view full size image 1 or image 2
The image mosaic of 18 randomly positioned copies of the same star, served as the
starting point for the alignment process. To complete the first stage of alignment, the
team moved the primary mirror segments to arrange the dots of starlight into a
hexagonal image array. On the overlay, each dot of starlight is labeled with the
corresponding mirror segment that captured it. Credits: NASA/STScI/J. DePasquale

The Webb team continues to make progress in aligning the observatory’s mirrors. Engineers have completed the first stage in this process, called “Segment Image Identification.” The resulting image shows that the team has moved each of Webb’s 18 primary mirror segments to bring 18 unfocused copies of a single star into a planned hexagonal formation.

With the image array complete, the team has now begun the second phase of alignment: “Segment Alignment.” During this stage, the team will correct large positioning errors of the mirror segments and update the alignment of the secondary mirror, making each individual dot of starlight more focused. When this “global alignment” is complete, the team will begin the third phase, called “Image Stacking,” which will bring the 18 spots of light on top of each other.

“We steer the segment dots into this array so that they have the same relative locations as the physical mirrors,” said Matthew Lallo, systems scientist and Telescopes Branch manager at the Space Telescope Science Institute. “During global alignment and Image Stacking, this familiar arrangement gives the wavefront team an intuitive and natural way of visualizing changes in the segment spots in the context of the entire primary mirror. We can now actually watch the primary mirror slowly form into its precise, intended shape!”
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Webb Mirror Alignment Continues Successfully

Post by bystander » Mon Feb 28, 2022 4:29 am

Webb Mirror Alignment Continues Successfully
NASA | JWST | 2022 Feb 25
Click to view full size image 1 or image 2
This hexagonal image array captured by the NIRCam instrument shows the progress
made during the Segment Alignment phase, further aligning Webb’s 18 primary
mirror segments and secondary mirror using precise movements commanded from
the ground. During the phase of alignment known as Image Stacking, individual
segment images are moved so they fall precisely at the center of the field to
produce one unified image instead of 18. In this image, all 18 segments are on
top of each other. After future alignment steps, the image will be even sharper.
Credit: NASA/STScI

Webb continues on its path to becoming a focused observatory. The team has successfully worked through the second and third out of seven total phases of mirror alignment. With the completion of these phases, called Segment Alignment and Image Stacking, the team will now begin making smaller adjustments to the positions of Webb’s mirrors.

After moving what were 18 scattered dots of starlight into Webb’s signature hexagonal formation, the team refined each mirror segment’s image by making minor adjustments, while also changing the alignment of Webb’s secondary mirror. The completion of this process, known as Segment Alignment, was a key step prior to overlapping the light from all the mirrors so that they can work in unison.

Once Segment Alignment was achieved, the focused dots reflected by each mirror were then stacked on top of each other, delivering photons of light from each segment to the same location on NIRCam’s sensor. During this process, called Image Stacking, the team activated sets of six mirrors at a time and commanded them to repoint their light to overlap, until all dots of starlight overlapped with each other. ...

Although Image Stacking put all the light from a star in one place on NIRCam’s detector, the mirror segments are still acting as 18 small telescopes rather than one big one. The segments now need to be lined up to each other with an accuracy smaller than the wavelength of the light.

The team is now starting the fourth phase of mirror alignment, known as Coarse Phasing, where NIRCam is used to capture light spectra from 20 separate pairings of mirror segments. This helps the team identify and correct vertical displacement between the mirror segments, or small differences in their heights. This will make the single dot of starlight progressively sharper and more focused in the coming weeks.
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Re: James Webb Space Telescope (JWST)

Post by Orca » Fri Mar 25, 2022 9:44 pm

"Test image" of an unremarkable star, for alignment purposes, and Webb has already begun capturing faint galaxies: https://www.space.com/james-webb-space- ... cted-image

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Re: James Webb Space Telescope (JWST)

Post by Fred the Cat » Sat Apr 09, 2022 4:46 pm

8-) and getting 8-) er :wink:
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NASA: Webb In Full Focus, Ready for Instrument Commissioning

Post by bystander » Tue May 03, 2022 4:45 pm

Webb In Full Focus, Ready for Instrument Commissioning
NASA | James Webb Space Telescope | 2022 Apr 28
webb_img_sharpness_details_v2-1200x635[1].png
Engineering images of sharply focused stars in the field of view of each instrument demonstrate
that the telescope is fully aligned and in focus. For this test, Webb pointed at part of the Large
Magellanic Cloud, a small satellite galaxy of the Milky Way, providing a dense field of hundreds
of thousands of stars across all the observatory’s sensors. The sizes and positions of the images
shown here depict the relative arrangement of each of Webb’s instruments in the telescope’s
focal plane, each pointing at a slightly offset part of the sky relative to one another. Webb’s three
imaging instruments are NIRCam (images shown here at a wavelength of 2 microns), NIRISS
(image shown here at 1.5 microns), and MIRI (shown at 7.7 microns, a longer wavelength
revealing emission from interstellar clouds as well as starlight). NIRSpec is a spectrograph rather
than imager but can take images, such as the 1.1 micron image shown here, for calibrations and
target acquisition. The dark regions visible in parts of the NIRSpec data are due to structures of
its microshutter array, which has several hundred thousand controllable shutters that can be
opened or shut to select which light is sent into the spectrograph. Lastly, Webb’s Fine Guidance
Sensor tracks guide stars to point the observatory accurately and precisely; its two sensors are not
generally used for scientific imaging but can take calibration images such as those shown here.
This image data is used not just to assess image sharpness but also to precisely measure and
calibrate subtle image distortions and alignments between sensors as part of Webb’s overall
instrument calibration process. Credit: NASA/STScI

Alignment of NASA’s 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. Upon completing the seventh and final stage of telescope alignment, the team held a set of key decision meetings and unanimously agreed that Webb is ready to move forward into its next and final series of preparations, known as science instrument commissioning. This process 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. ...

The optical performance of the telescope continues to be better than the engineering team’s most optimistic predictions. 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 “diffraction-limited,” meaning that the fineness of detail that can be seen is as good as physically possible given the size of the telescope. From this point forward the only changes to the mirrors will be very small, periodic adjustments to the primary mirror segments. ...

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. ...

Though telescope alignment is complete, some telescope calibration activities remain: 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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Know the quiet place within your heart and touch the rainbow of possibility; be
alive to the gentle breeze of communication, and please stop being such a jerk.
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