The Webb Telescope

@contenchess said
I was just wondering when we were going to see a picture or two...

3 months? 🤷

@liljo said
Yes sir, three months or maybe more before it is fully operational, 100% focused and all lined out.

They are adjusting those mirrors right now less than the width of a human hair at a time! And one at a time at that!

@jimm619
Which is equal to a 48 inch scope, it can't compete with Hubble just yet.....

I just hope the mirror adjustors keep working, one dead mirror and it doesn't work as well...

The Webb is chilling nicely, as you can imagine!

Primary Mirror Assembly: -377 F
Th-th-th-that's cold.

Now that they have looked at the first star, they are just about finished with "segment ID" where each of the 18 points of light are identified with their respective mirrors. This is towards completion, and the next stage, individual segment alignment is underway. Midway through this process, they will begin the stage referred to as "Image Stacking" where each of those 18 individual points of light will come together to form an image of the single star they all represent.

Following all of these tasks, there will be another two months of other tasks to complete before the absolutely most amazing images in mankind's history begin to come in.

Astronomy Magazine has always been great to have a subscription to. But it is about to get a lot better!

@Liljo
I think there must be some kind of adjustments to focal points of each mirror besides just the aiming problem where you want all 18 segments to aim precisely at a target.
But what I saw was each point of light was not a point but a blob needing correction, each one, not the total together, so there is clearly more work going on.
It is amazing they can do ANYTHING with that scope being a million miles from home.

I wonder what the data rate is from the high gain antenna onboard?

@sonhouse said
@Liljo
I think there must be some kind of adjustments to focal points of each mirror besides just the aiming problem where you want all 18 segments to aim precisely at a target.
But what I saw was each point of light was not a point but a blob needing correction, each one, not the total together, so there is clearly more work going on.
It is amazing they can do ANYTHING w ...[text shortened]... ing a million miles from home.

I wonder what the data rate is from the high gain antenna onboard?

@Ponderable
Not bad for being a million miles away.
I had a little thrill at Goddard, in class room exercise I had to find Mars, the angles and such, I think it was some 50 million miles away ATT then turn the student antenna dish, small dish, something like 12 feet in diameter.
Anyway, the object of the exercise was to lock on the phase modulators to the signal of a Mars probe in orbit sending data back to Earh.
I'm sure the data rate was nothing like 20 or so megabits/second but I found where Mars was, the exact angles, and the little dish was able to lock on to that probe.

I was thinking, so here is that transmitter on the Mars orbiter, power of 5 watts.
I'm thinking 5 watts is the same power allowed by CB radios which poop out after 10 or 20 miles,
for line of sight transmissions but of course CB and ham radios do reach out across the world, but just line of sight with little ionosphere activation because we are in the low end of the 11 year solar cycle but that probe was communicating with Earth with that same amount of power. I never thought I would see the 'locked' button light up when phase lock happened. Phase lock is where you can actually start extracting data.
We classmates were not that advanced for that exercise, all we had to do was figure out where the hell Mars was in the daylight sky, get the dish located on target and then establish phase lock, was a great day among many such at Goddard.

Update:
The Webb Telescope is undergoing the fourth of seven stages to become fully operational. It is called "course phasing" and will occur in increments three different times. The next phase is called "fine phasing" and will also occur three times.

All is going well according to every report I can find. Telescope alignment and final corrections will follow the fine phasing stage. The primary mirror average temp is now -380F.

https://www.jwst.nasa.gov/content/webbLaunch/whereIsWebb.html

@liljo said
Update:
The Webb Telescope is undergoing the fourth of seven stages to become fully operational. It is called "course phasing" and will occur in increments three different times. The next phase is called "fine phasing" and will also occur three times.

All is going well according to every report I can find. Telescope alignment and final corrections will follow the fine phasi ...[text shortened]... y mirror average temp is now -380F.

https://www.jwst.nasa.gov/content/webbLaunch/whereIsWebb.html

@ponderable said
This is 45 K...so oxygen and nitrogen at these temperatures are solids...

@Liljo
What was the temperature goal? I saw they got the images all aligned on one point now but still have to fine tune the images to make it one giant scope.

@sonhouse said
@Liljo
What was the temperature goal? I saw they got the images all aligned on one point now but still have to fine tune the images to make it one giant scope.

@Liljo
Yep, the 18 mirrors are all making one image now instead of 18 so next is fine tuning the focus of each mirror. I saw the combined image needed some TLC, not ready for prime time as of yet.

The first picture I saw (I am a bit frustrated about the headline by phys.org, since of course it was not photobombed, but we got already a glimpse of what the device is set up to do...):

https://phys.org/news/2022-03-space-telescope-image-star-photobombed.html

@Ponderable
That star had spikes sticking out because it is the result of the edges of each mirror not exactly matching and probably that is as good as it is going to get. That star is way too strong for a scope as sensitive as the Webb.
The real work will be on targets a million times dimmer.