JWST Countdown To Terror 😳

[F15Rules]

Fascinating and uplifting stuff..human beings at their best, working across nations, collaboratively and so calm..

That's the value of all those months and years of practice, practice and more practice..then great execution👍.

Dave

[Sunshine]

Looks like secondary is fully deployed!

[Highburymark]

1 hour ago, F15Rules said:

Fascinating and uplifting stuff..human beings at their best, working across nations, collaboratively and so calm..

That's the value of all those months and years of practice, practice and more practice..then great execution👍.

Dave

Totally agree Dave. Sir Isaac would be proud.

[Ags]

If the sunshield is the "ground", can we classify the JWST as a truss tube Dob?

[tomato]

It would be quite a feat to look through a hole in the primary mirror of a terrestrial Dobsonian.☺️

I’m sure it won’t happen but I guess if the hinged sections of the primary failed to deploy, we still have a mission but with reduced capability?
 

It’s fading into history now but what a great job done by the Ariane 5 launch vehicle, way to go ESA!

[Stu]

30 minutes ago, tomato said:

I’m sure it won’t happen but I guess if the hinged sections of the primary failed to deploy, we still have a mission but with reduced capability?

I saw somewhere that they need at least one side to work to get what they want, but I can’t recall where I saw that. Ultimately I can’t see why it won’t work as it is, with reduced light gathering. Someone in NASA said ‘we have a telescope’ after the secondary deployed which backs that up.

[Macavity]

18 minutes ago, Stu said:

I saw somewhere that they need at least one side to work to get what they want, but I can’t recall where I saw that. Ultimately I can’t see why it won’t work as it is, with reduced light gathering. Someone in NASA said ‘we have a telescope’ after the secondary deployed which backs that up.

A good point? Many of us have had to "stop down" for some reason?
The quibble between FULL aperture and "No telescope at all"
seems to be less important for many of us? 😅

Edited January 6, 2022 by Macavity

[Zermelo]

21 minutes ago, Stu said:

I saw somewhere that they need at least one side to work to get what they want, but I can’t recall where I saw that

It was probably the first post in this thread

[kirkster501]

I read it on one of the technical articles on University of Arizona website last year and shared on the thread. Something to do with the wavelength of the IR light and a certain amount of mirror area they need in order to gather enough light for the IR instruments or else they will not work properly.  Remember JWST is an IR telescope operating at much longer wavelengths than the HST.

The resolution of the images that Webb will produce (even with both mirror wings properly deployed) will not be any higher than the HST because Webb is operating in the IR and so needs a correspondingly larger mirror for the same resolution as the HST does in visible light.

This is why LUVOIR, operating in the visible light spectrum, BUT with a huge mirror 15m across will be truly outstanding if it is ever built.  That huge mirror and visible light wavelengths!

[Macavity]

Some interesting comments (I felt!) on various LIVE FEEDS re. "Wot no Cameras"? 🥳
Not just "weight", but that the JWST changes (bigly!) re. "geometry"! - Would need
*multiple* cameras - and associated electronics. "Contrast"! Ab-initio development
of low temperature Camera Technology? The problem of heating the telescope etc.

I DO (sometimes) have a bit of "pop" at NASA - But I understand / forgive them.! 😏

Edited January 6, 2022 by Macavity

[Laurieast]

NASA TV 

I'm not seeing any mention of coverage of the first wing?

January 7, Friday
TBD - Live coverage of the unfolding of the second of the James Webb Space Telescope's primary mirror wings, marking the end of the observatory deployments. The time of the broadcast will be posted here and the James Webb Space Telescope's blog when it is announced. 
TBD - NASA will hold a media briefing as soon as possible after the end of the live broadcast coverage of Webb’s final deployments. The time of the press conference will be posted here and the James Webb Space Telescope's blog when it is announced. 

 

[AstroKeith]

9 minutes ago, Macavity said:

Some interesting comments (I felt!) on various LIVE FEEDS re. "Wot no Cameras"! 🥳
Not just "weight", but that the JWST changes (bigly!) re. "geometry"! - Would need
*multiple* cameras (and associated) electronics. "Contrast"! Ab-initio development
of low temperature Camera Technology. The problem of heating the telescope etc.

I DO (sometimes) have a bit of "pop" at NASA - But understand / forgive more... 😏

I got mesmerised by that feed while I was watching yesterday.

At first I was appalled by most of the comments, but then I got saddened when I realised it was down to (mostly) sheer ignorance. But even the ignorant had taken no effort to find answers, they were just posting questions and statements.

Then there were the stupid posts. I include conspiracy theorists in this category.

Then there were countless posts from people just saying 'hi'.

[kirkster501]

14 minutes ago, Macavity said:

Some interesting comments (I felt!) on various LIVE FEEDS re. "Wot no Cameras"? 🥳
Not just "weight", but that the JWST changes (bigly!) re. "geometry"! - Would need
*multiple* cameras - and associated electronics. "Contrast"! Ab-initio development
of low temperature Camera Technology? The problem of heating the telescope etc.

I DO (sometimes) have a bit of "pop" at NASA - But I understand / forgive them.! 😏

We live in a Facetime/Teams/Zoom society where webcam/video is seen as second nature (more so since the pandemic started(). However, the cold side of Webb is as black as night - literally.  How would that be lit so that a potential "camera" could see what was going on?  How would a camerra operate at -200C?  What about the wiring and software for these cameras?  How many such cameras?  True, the IR instruments themselves operate at that temperature, but they cost hundreds of millions to build.  They weighed the camera idea up and in the end decided they could achieve what they needed to without them by instrumentation.

[AstroKeith]

17 minutes ago, Laurieast said:

NASA TV 

I'm not seeing any mention of coverage of the first wing?

January 7, Friday
TBD - Live coverage of the unfolding of the second of the James Webb Space Telescope's primary mirror wings, marking the end of the observatory deployments. The time of the broadcast will be posted here and the James Webb Space Telescope's blog when it is announced. 
TBD - NASA will hold a media briefing as soon as possible after the end of the live broadcast coverage of Webb’s final deployments. The time of the press conference will be posted here and the James Webb Space Telescope's blog when it is announced. 

 

They do seem to be slow at updating some of their info pages (busy doing deployments?!).

Next stage is the Aft Deployable Instrument Radiator.

[Stu]

59 minutes ago, Zermelo said:

It was probably the first post in this thread

 

On 14/12/2021 at 18:00, kirkster501 said:

5.  At least one side of the foldable mirror HAS to fold out.   JWST needs at least 15 segments.

Indeed it was! 👍

[Macavity]

16 minutes ago, kirkster501 said:

We live in a Facetime/Teams/Zoom society where webcam/video is seen as second nature...

Heheh. I do love the "slightly awkward" commentaries by REAL Scientists - Engineers,
Technicians etc. The guys/gals who have "Busted a Gut" to BUILD these things etc! 😎
In my less cynical moods, I still sense there are "young people" who feel the same...

I empathise with the (Ph.D?) host who had to explain that "in science" (programs)
things might not always "go to plan"?!?! For some of their audience, a revelation?! 🤔

Ignore the dissenters! I still believe there are fellow Nerds *Enthusiasts* out there?! 🥳

[tomato]

With regard to the lack of cameras, it is an extremely (and expensive) serious scientific endeavour, not a social media exercise, so I can live without camera feeds.

I would rather see what the JWST can discover about the very early universe and the nature of exoplanets rather than it take selfies. We can let Starlink take care of that.😉

[Ian McCallum]

5 minutes ago, tomato said:

With regard to the lack of cameras, it is an extremely (and expensive) serious scientific endeavour, not a social media exercise, so I can live without camera feeds.

I would rather see what the JWST can discover about the very early universe and the nature of exoplanets rather than it take selfies. We can let Starlink take care of that.😉

Indeed, the JWST is designed to look outwards, not have cameras strapped to it to take selfies!👍

[Alien 13]

8 minutes ago, tomato said:

With regard to the lack of cameras, it is an extremely (and expensive) serious scientific endeavour, not a social media exercise, so I can live without camera feeds.

I would rather see what the JWST can discover about the very early universe and the nature of exoplanets rather than it take selfies. We can let Starlink take care of that.😉

 

2 minutes ago, Ian McCallum said:

Indeed, the JWST is designed to look outwards, not have cameras strapped to it to take selfies!👍

Agreed to some extent but a camera is a wonderful diagnostic tool, like the old saying "a picture is worth a thousand lines of code" if a problem needs fixing.

Alan

[Zermelo]

https://xkcd.com/2564/

 

[andrew s]

All the selfie cameras in the world would not have shown Hubble's myopia! 

They do, however help keep the paying public engaged. 

Regards Andrew 

[Ags]

36 minutes ago, Alien 13 said:

 

Agreed to some extent but a camera is a wonderful diagnostic tool, like the old saying "a picture is worth a thousand lines of code" if a problem needs fixing.

Alan

I can see two cameras that would be useful: one showing the primary mirror to inspect for damage, and another showing the sunshield, again for damage inspection.

[Stu]

1 hour ago, tomato said:

With regard to the lack of cameras, it is an extremely (and expensive) serious scientific endeavour, not a social media exercise, so I can live without camera feeds.

I would rather see what the JWST can discover about the very early universe and the nature of exoplanets rather than it take selfies. We can let Starlink take care of that.😉

Agreed 100%! 

[Nicola Fletcher]

Does anyone know if there is any way to be sent an alert with the times of the live coverage? I keep missing them!

 

[Laurieast]

15 minutes ago, Nicola Fletcher said:

Does anyone know if there is any way to be sent an alert with the times of the live coverage? I keep missing them!

https://www.nasa.gov/nasalive

I'm not aware of any alert, just keep checking the schedule frequently. Or keep it running on another screen just to be sure!

Edited January 6, 2022 by Laurieast