The James Webb Space Telescope

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The James Webb Space Telescope (JWST) is scheduled to launch no earlier than December 24, following a two-day delay, with a critical launch window extending to January 6 due to gravitational concerns. Enthusiasm is high among the community, with many eagerly anticipating the scientific data it will provide, despite concerns over the lengthy wait and significant costs associated with the project. Initial observing time has been allocated for various proposals, including a major project called Cosmos Web, which aims to capture detailed images of the early universe. The mission's success is seen as a gamble, with many previous missions sacrificed for JWST funding, raising questions about the return on investment. As the launch approaches, excitement and nervousness are palpable, with many setting alarms to witness the event live.
  • #241
Telescope alignment has been completed and all instruments are in focus already, so we are a bit ahead of schedule.
 
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  • #242
mfb said:
so we are a bit ahead of schedule.
That is great news, I understand that JWST is a bit overbooked for observing time.
 
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  • #243
The first 12 months are already booked in according to the NASA site. It is keeping exactly what will be the first targets secret.

@Oldman too
 
  • #244
pinball1970 said:
The first 12 months are already booked in according to the NASA site. It is keeping exactly what will be the first targets secret.

@Oldman too
They do seem to be leaking hints, I'll see if I can find links to what I've seen so far.
 
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  • #245
Hi @pinball1970 , It looks like there isn't a particular observation schedule because of the Time Constrained Feature. I could be wrong but it looks like https://www.stsci.edu/jwst/science-execution/approved-ers-programs is the early favorite list, contingent on this feature, https://jwst-docs.stsci.edu/jwst-opportunities-and-policies/jwst-call-for-proposals-for-cycle-1/jwst-cycle-1-observation-types-and-restrictions/time-constrained-observations This is in addition to the cycle 1 GTO and GO as well as the all important
https://www.stsci.edu/jwst/science-execution/approved-programs/cycle-1-calibration Researchers still have to learn the science systems since it's a new to everyone.
 
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  • #249
Oldman too said:
Brilliant!

They need a new graphic now though.

Otherwise we will just sit at “stage 7 complete” for the next two months.

1651235353703.png
 
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  • #250
pinball1970 said:
Otherwise we will just sit at “stage 7 complete” for the next two months.
That would be such a cruel irony, (considering how smoothly the progress has been so far) they They must be planning some type of sideshow.
 
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  • #251
pinball1970 said:
Brilliant!

They need a new graphic now though.

Otherwise we will just sit at “stage 7 complete” for the next two months.

Oldman too said:
That would be such a cruel irony, (considering how smoothly the progress has been so far) they They must be planning some type of sideshow.

NASA graphics have made small changes https://webb.nasa.gov/content/webbLaunch/whereIsWebb.html

Smallish. This is NASA though, I will take it.

Today

1651581592474.png


Last week

1651581611956.png
 
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  • #252
pinball1970 said:
I had no need to worry.
I know, I just want to be able to say that after science operations begins. An amazing job so far though.

pinball1970 said:
They have pushed back the curser on the progress line, we are now only 84% of the way along whereas last week we were at 98%.
I guess that's one way to define progress.
 
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  • #253
Oldman too said:
I know, I just want to be able to say that after science operations begins. An amazing job so far though.I guess that's one way to define progress.
I was being a tad facetious. Obviously everything has gone like clock work so far and that's great. However since we cannot see it and we are not getting images (besides those few cool images) it's nice to see each milestone pass successfully and the next few goals.
Let's see what they do.
 
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  • #254
Have you seen this image? How's that for progress??!
IR_Telescope_Comparison_03May22.png
 
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  • #255
That's a bit misleading - WISE is actually younger (2009/10) than Spitzer (2003). It just had a smaller primary mirror (40cm vs Spitzer's 85cm, if Wikipedia is to be believed), presumably because WISE was a sky survey instrument.

Webb, of course, has a 6.5m main mirror.
 
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  • #256
phyzguy said:
Have you seen this image? How's that for progress??!View attachment 300975
Amazing! Tremendously amazing!
 
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  • #257
Oldman too said:
I guess that's one way to define progress.

It is a computer science tradition. The progress bar chugs along until it gets to 95% then freezes.
 
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  • #258
phyzguy said:
Have you seen this image? How's that for progress??!View attachment 300975

Ibix said:
That's a bit misleading - WISE is actually younger (2009/10) than Spitzer (2003). It just had a smaller primary mirror (40cm vs Spitzer's 85cm, if Wikipedia is to be believed), presumably because WISE was a sky survey instrument.

Webb, of course, has a 6.5m main mirror.
I saw those images on youtube and was sceptical as I do not know enough about the technology to judge if the comparison was fair or not.

The first image on WISE looks like its pixels have been blown up. So it would look blurred compared to the other two.

I found this discussion.

https://www.universetoday.com/15568...compare-webb-to-other-infrared-observatories/
 
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  • #259
pinball1970 said:
The first image on WISE looks like its pixels have been blown up. So it would look blurred compared to the other two.
You'd pick your pixel size to match the telescope resolution, so the smaller telescopes would have fewer pixels in an image of the same region of sky. There's no point in spending lots of money getting a super fine grid on a big blur, and you'd get fewer photons per pixel into the bargain. So the size of the blobs of light is a function of the optics, and the size of the pixels is a function of how big you calculate the blobs are going to be. Notice that the biggest blob just above the center of the image is ~10 pixels across in both the WISE and Spitzer images.
 
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  • #262
All the numbers are now the same brightness. So not greyed out.
Screenshot_2022-05-13-13-19-56.png
Screenshot_2022-05-14-14-13-44.png

There is the big tick too, I love the big tick! The press conference said the number of checks now out of 1000s was now at 200 or so but that was on the 9th May.
 
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  • #264
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  • #265
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  • #266
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  • #267
The instrument checkout page has a first completed item, images with NIRCam.

There are rumors that 55 Cancri might be one of the first, or even the first, target. It has five known exoplanets, the innermost orbits the star in less than a day.
 
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  • #268
mfb said:
On the where is Webb? page that has been linked multiple times.Deployable Tower Assembly is in progress.
I have tried Where's Webb from 6.30am BST till now. It never fails on my desk top and never mid week. Can you access?
Edit. Where's Webb is back. Normal. Nominal.
 
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  • #270
mfb said:
NIRISS now has "Imaging (parallel only)" as completed step.

One mirror segment was hit by a larger than expected micrometeoroid. The impact on data-taking is likely small but they are still studying it.
This is a from DEC 2017

https://www.nasa.gov/feature/goddar...-about-the-toughness-of-nasa-s-webb-telescope

“Q: Once Webb is in orbit, how susceptible will it be to micrometeoroid strikes? For example, what would happen if one of Webb’s primary mirror segments or the sunshield got struck?

Paul: Although space is mostly empty, there is some debris. In the inner Solar System where Webb will orbit, we have a good understanding of what the population of meteoroids is like from years of observations and research. It’s mostly dust and very small particles, with the majority being sparsely distributed and tinier than grains of sand. There are some pebbles, rocks, and boulders, but they are very sparse and very rare. At Webb’s orbit at L2, the debris is all natural and the environment is not as hazardous as it is much closer to Earth, where there is a fair amount of human-generated “space junk.”

We know Webb will get struck by micrometeoroids during its lifetime, and we have taken that into account in its design and construction. We sized Webb’s main mirror so that even after years of little impacts it will still have the reflective surface area and quality necessary to do the science. We even did tests on the ground that emulated micrometeoroid impacts to demonstrate what will happen to the mirrors in space.

Similarly, part of the reason the sunshield has five layers is so it can tolerate more than the number of expected small holes, and even some tears, and still work as it should.
Also, almost all of Webb’s sensitive components (besides the mirrors and sunshield) are protected behind “micrometeoroid armor.” When micrometeoroids do strike, most are so small that they totally disintegrate upon impact, even when they hit something thin like thermal blankets or a sunshield membrane. Critical wires and electronics are shielded behind even more robust metal “armor” or inside metal boxes.”
So when you say, “larger than expected” you mean from the data they had on the environment at L2 prior to launch?

The site was down for a while, any connection? Or was that just to update the instrument completion?
 
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