James Webb Space Telescope passes key alignment phase

Shawn Knight

Posts: 14,141   +154
Staff member
What just happened? NASA recently completed a series of critical mirror alignment steps on the James Webb Space Telescope. During the "fine phasing" stage, NASA had to check and test every optical parameter to ensure it is performing at, or above, expectations. No issues were encountered, leaving the team confident that Webb's optical performance will indeed meet or exceed the goals it was designed to achieve.

"We have fully aligned and focused the telescope on a star, and the performance is beating specifications. We are excited about what this means for science," said Ritva Keski-Kuha, deputy optical telescope element manager for Webb at NASA Goddard. "We now know we have built the right telescope."

Furthermore, NASA found zero critical issues and no measurable contamination or blockages in Webb's optical path. As such, the telescope is able to gather light from distant objects and deliver it to various onboard instruments without issue.

NASA captured the image above of a star known as 2MASS J17554042+6551277 to evaluate the recently completed alignment phase. The target is the bright spot in the middle, but because Webb's optics and the Near Infrared Camera (NIRCam) instrument – Webb's primary image sensor – are so sensitive, several other stars and galaxies also show up in the background. A red filter was used in the image to optimize visual contrast, NASA said.

The Webb team will spend the next six weeks completing the remaining alignment steps ahead of final science instrument preparations, which could start in early May or sooner. The first full-resolution imagery and science data is expected to be released this summer.

Permalink to story.

 

tygrus

Posts: 25   +10
I would have thought the start bursts seen in these images are caused mostly by imperfect optics, maybe the extreme distances or were they exaggerated during post-processing to make them look like twinkly stars to the viewer (2022-03-17-image-19-j)?
 

Badvok

Posts: 348   +179
I would have thought the start bursts seen in these images are caused mostly by imperfect optics, maybe the extreme distances or were they exaggerated during post-processing to make them look like twinkly stars to the viewer (2022-03-17-image-19-j)?
My thoughts exactly. Perhaps the very structure of the telescope means they aren't able to eliminate these imperfections and will have to compensate for them.
 

BadThad

Posts: 1,039   +1,193
One of mankind's crowning achievements! The galaxies seen in the image are previously unknown ones. The majority of the scientists excitement was over these inadvertent detections. Given the complexity of the entire project and huge number of things that could have gone wrong - this is without doubt NASA's greatest achievement.
 

BadThad

Posts: 1,039   +1,193
I would have thought the start bursts seen in these images are caused mostly by imperfect optics, maybe the extreme distances or were they exaggerated during post-processing to make them look like twinkly stars to the viewer (2022-03-17-image-19-j)?

Those are artifacts from the IR detector that correspond to the mirror shapes. There's still a lot of alignment and calibration to be done, these will be corrected-out later.
 

wiyosaya

Posts: 7,706   +6,653
Those are artifacts from the IR detector that correspond to the mirror shapes. There's still a lot of alignment and calibration to be done, these will be corrected-out later.
Yes, there is still a fine alignment phase that they have to go through. The capabilities of the alignment hardware are amazing, IMO. They can align the mirror segments within nanometers. Truly astounding.

Still, though, the image in the story looks like it is diffracted, and there is a limit to how good the image will be no matter the optics - https://en.wikipedia.org/wiki/Diffraction-limited_system That said, the image, barring no unforeseen problems (so far, everything has worked perfectly) the images should be of unequaled quality.

EDIT:
One of mankind's crowning achievements! The galaxies seen in the image are previously unknown ones. The majority of the scientists excitement was over these inadvertent detections. Given the complexity of the entire project and huge number of things that could have gone wrong - this is without doubt NASA's greatest achievement.
We can expect more unexpected discoveries from this baby!
 

Avro Arrow

Posts: 2,373   +2,886
TechSpot Elite
It's great news but if the performance is EXCEEDING expectations, then the people who designed it weren't fully aware of what they were doing. I think that their expectations should have been more accurate. :laughing:
 

Aaron Fox

Posts: 153   +90
Great scientists. Poor management.

NASA could have done better than to name the project after someone who purged a minority from their jobs to keep his own. America could have stood for something better.