JWST Grand opening

[SteveB]

Hi all.
The present day goal is July 12, 2022 for the James Webb Space Telescope to start showing imagery.

Webb Image Galleries - NASA Science

Latest Images – 2024 Webb’s most recent images released by NASA in 2024, displayed in reverse chronological order. The image below is a SLIDESHOW. Hover over the image to see the image title and controls. Click the image to go to a detail page with more info and the ability to download the image...

www.nasa.gov

So, for those who have been waiting with baited breath.....

3 weeks and a day....

 

[4tune8chance]

Bit of bad news, one of the primary mirror segments was struck by a micrometeorite, not sure if functionality will be affected.

 

[SteveB]

Bit of bad news, one of the primary mirror segments was struck by a micrometeorite, not sure if functionality will be affected.

Yesterday's report said it won't be a problem.

Considering that it's over a million miles away, and servicing it won't be a viable option, I'd say that they took all of these things into consideration when building it.

FAQ Full General Public Webb Telescope/NASA

James Webb Space Telescope

www.jwst.nasa.gov

 

[inertia]

Bit of bad news, one of the primary mirror segments was struck by a micrometeorite, not sure if functionality will be affected.

The good news is that optical engineers anticipated micrometeor strikes and added margin into the design in order to maintain enough performance for scientific missions.

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[inertia]

Hi all.
The present day goal is July 12, 2022 for the James Webb Space Telescope to start showing imagery.

Webb Image Galleries - NASA Science

Latest Images – 2024 Webb’s most recent images released by NASA in 2024, displayed in reverse chronological order. The image below is a SLIDESHOW. Hover over the image to see the image title and controls. Click the image to go to a detail page with more info and the ability to download the image...

www.nasa.gov

So, for those who have been waiting with baited breath.....

3 weeks and a day....

Anticipation: It's making me wait.

Metrics: specifications include diffraction from the primary mirror aperture and secondary mirror strut obscurations

Resolution: 0.1 arcsec
Waveband: 0.6 - 28.5 microns
Strehl Ratio > 0.8 (at 2 microns) Note: diffraction limited performance occurs at 0.8

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Reference: Ball Aerospace optical performance characteristics

 

[4tune8chance]

Yesterday's report said it won't be a problem.

Considering that it's over a million miles away, and servicing it won't be a viable option, I'd say that they took all of these things into consideration when building it.

FAQ Full General Public Webb Telescope/NASA

James Webb Space Telescope

www.jwst.nasa.gov

Lets hope so. I wonder how they compensate for damage, some sort of software solution where it subtracts that part of the mirror?

 

[SteveB]

Lets hope so. I wonder how they compensate for damage, some sort of software solution where it subtracts that part of the mirror?

You sound like you think the damage is a lot.

Just how much do you think it is?

 

[inertia]

Lets hope so. I wonder how they compensate for damage, some sort of software solution where it subtracts that part of the mirror?

James Webb engineers employed adaptive optics to actively control and compensate for optical aberrations. For earth-locked telescopes adaptive optics are incorporated to remove aberrations caused by atmospheric turbulence and aberrations caused by internally generated issues such as misalignment, pits in optics and diffraction from struts for example.

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[4tune8chance]

You sound like you think the damage is a lot.

Just how much do you think it is?

I was listening to the podcast 'Astronomy Cast' episode 646, where they stated (from memory) the impact was a little bit bigger than current measures could compensate, but still waiting on clarification.

 

[4tune8chance]

James Webb engineers employed adaptive optics to actively control and compensate for optical aberrations. For earth-locked telescopes adaptive optics are incorporated to remove aberrations caused by atmospheric turbulence and aberrations caused by internally generated issues such as misalignment, pits in optics and diffraction from struts for example.

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I really hope it can compensate. In a standard mirror you just paint over a chip and wait until the next mirror overhaul. Adaptive optics is really a big solution for fine tuning the entire surface, but it's entirely feasible I would think, that you could permanently lower one controller below the chipped area such that it would take it out of the observing surface. Although if the chip is an awkward shape reflections in multiple directions might be problematic.

 

[inertia]

I really hope it can compensate. In a standard mirror you just paint over a chip and wait until the next mirror overhaul. Adaptive optics is really a big solution for fine tuning the entire surface, but it's entirely feasible I would think, that you could permanently lower one controller below the chipped area such that it would take it out of the observing surface. Although if the chip is an awkward shape reflections in multiple directions might be problematic.

I stand corrected. As it turns out the telescope only employs active optics instead of adaptive optics to help correct optical aberrations that engineers expect to encounter over time. Adaptive optics in a space environment is overkill because wavefront aberrations in space occur at a rate orders-of-magnitude slower than aberrations caused from atmospheric turbulence.

For those that are inclined to watch, here is a presentation from a long ago friend of mine: FSM = fine steering mirror

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