# James Webb Space Telescope general discussion thread **URL:** \ **Category:** Miscellaneous and Personal Stuff I Must Share\ **Tags:** science-math\ **Created:** [December 25, 2021, 1:18pm UTC](https://boards.straightdope.com/t/james-webb-space-telescope-general-discussion-thread/956624 "2021-12-25T13:18:56Z")\ **Posts on this page:** 20\ **Page:** 8
**Author:** ![gnoitall](https://avatars.discourse-cdn.com/v4/letter/g/bb73d2/32.png) [@gnoitall](https://boards.straightdope.com/u/gnoitall)\ **Post date:** [January 3, 2022, 12:51am UTC](https://boards.straightdope.com/t/james-webb-space-telescope-general-discussion-thread/956624/141 "2022-01-03T00:51:39Z")
> [@Dr.Strangelove](#): > > The page uses metric internally. I found this bit of Javascript: > `_0x5a8556(0x138)]=Number(g['tempCoolSide1C']*(0x9/0x5)+0x20` With the conversion constants in hexadecimal, FFS. 🤦‍♂️ Unless that’s just an artifact of the debugger you’re using to look at the code? ---
**Author:** ![Gorsnak](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gorsnak/32/7587_2.png) [@Gorsnak](https://boards.straightdope.com/u/Gorsnak)\ **Post date:** [January 3, 2022, 1:53am UTC](https://boards.straightdope.com/t/james-webb-space-telescope-general-discussion-thread/956624/142 "2022-01-03T01:53:41Z")
> [@wolfpup](#): > > Back on topic, we are past due on some updates about the sun shield tensioning. It’s obviously working as the cold side is now impressively chilly, but although tensioning is supposed to take about two days, “start” and “completion” are two separate milestones. Hope all is well. They’ve juggled the deployment schedule a bit. [https://blogs.nasa.gov/webb/2022/01/02/deployment-timeline-adjusted-as-team-focuses-on-observatory-operations/](https://blogs.nasa.gov/webb/2022/01/02/deployment-timeline-adjusted-as-team-focuses-on-observatory-operations/) ---
**Author:** ![Dr.Strangelove](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dr.strangelove/32/6613_2.png) [@Dr.Strangelove](https://boards.straightdope.com/u/Dr.Strangelove)\ **Post date:** [January 3, 2022, 1:59am UTC](https://boards.straightdope.com/t/james-webb-space-telescope-general-discussion-thread/956624/143 "2022-01-03T01:59:52Z")
> [@gnoitall](#): > > Unless that’s just an artifact of the debugger you’re using to look at the code? No, that’s the straight text from the page. However, they clearly ran it through an obsucator, since all of the variable names are random hex codes (only the string constants are readable). May not have been intentional; I think some page generator frameworks will obfuscate by default. ---
**Author:** ![wolfpup](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/wolfpup/32/10618_2.png) [@wolfpup](https://boards.straightdope.com/u/wolfpup)\ **Post date:** [January 3, 2022, 2:19am UTC](https://boards.straightdope.com/t/james-webb-space-telescope-general-discussion-thread/956624/144 "2022-01-03T02:19:50Z")
Thanks for that! I was looking for news updates but didn’t see that. ---
**Author:** ![wolfpup](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/wolfpup/32/10618_2.png) [@wolfpup](https://boards.straightdope.com/u/wolfpup)\ **Post date:** [January 4, 2022, 1:22am UTC](https://boards.straightdope.com/t/james-webb-space-telescope-general-discussion-thread/956624/145 "2022-01-04T01:22:12Z")
They appear to have moved down the major mirror deployments by several days while they continue to dink around with whatever they’re dinking around with, per the earlier link. No indication of problems, just a delay because there’s no hurry and they’re taking time to check a lot of things out. ---
**Author:** ![Gorsnak](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gorsnak/32/7587_2.png) [@Gorsnak](https://boards.straightdope.com/u/Gorsnak)\ **Post date:** [January 4, 2022, 1:29am UTC](https://boards.straightdope.com/t/james-webb-space-telescope-general-discussion-thread/956624/146 "2022-01-04T01:29:44Z")
The blog page of the Webb site is now saying that the first three layers of the sunshield have been tensioned, so they seem to be proceeding with the deployment schedule. ---
**Author:** ![k9bfriender](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/k9bfriender/32/3283_2.png) [@k9bfriender](https://boards.straightdope.com/u/k9bfriender)\ **Post date:** [January 4, 2022, 3:07pm UTC](https://boards.straightdope.com/t/james-webb-space-telescope-general-discussion-thread/956624/147 "2022-01-04T15:07:52Z")
I suspect that it’s also a matter of committed time. Solar system objects have a much greater apparent brightness than distant galaxies. In order to collect enough light to get a good picture of them probably takes much less time. The Hubble Deep Field required about 140 hours of Hubble staring at a single spot, with the Ultra Deep Field taking 267 hours. I imagine that solar system objects will only need a fraction of an hour each to get a good view. Makes sense to start with the stuff that can be knocked out quickly, then once that’s all done, start doing these longer exposures to image further objects. Though, calibration is a good point as well. We have pretty good data on some of these solar system objects, so even though JWST may return more data than we currently have, we still have a pretty good idea of what it should look like. If it starts returning that Enceladus is made of cheese, then we know that there is some recalibrating to be done. ---
**Author:** ![Gorsnak](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gorsnak/32/7587_2.png) [@Gorsnak](https://boards.straightdope.com/u/Gorsnak)\ **Post date:** [January 4, 2022, 5:48pm UTC](https://boards.straightdope.com/t/james-webb-space-telescope-general-discussion-thread/956624/148 "2022-01-04T17:48:45Z")
Sunshield tensioning complete: > The phrase “344 single-point failures” is a little nightmare-inducing, I have to say. ---
**Author:** ![Folly](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/folly/32/3219_2.png) [@Folly](https://boards.straightdope.com/u/Folly)\ **Post date:** [January 4, 2022, 6:06pm UTC](https://boards.straightdope.com/t/james-webb-space-telescope-general-discussion-thread/956624/149 "2022-01-04T18:06:52Z")
> [@Gorsnak](#): > > nightmare-inducing Can’t have nightmares if you’re up in the middle of the night with anxiety sweats… ---
**Author:** ![N9IWP](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/n9iwp/32/3154_2.png) [@N9IWP](https://boards.straightdope.com/u/N9IWP)\ **Post date:** [January 4, 2022, 6:09pm UTC](https://boards.straightdope.com/t/james-webb-space-telescope-general-discussion-thread/956624/150 "2022-01-04T18:09:37Z")
Only ~86 single point failures to go… I wonder if some, while bad, would not be mission ending. If one of the two main mirror assemblies didn’t fold out, there would still be a lot of mirror segments available. Brian ---
**Author:** ![Magiver](https://avatars.discourse-cdn.com/v4/letter/m/4491bb/32.png) [@Magiver](https://boards.straightdope.com/u/Magiver)\ **Post date:** [January 4, 2022, 6:48pm UTC](https://boards.straightdope.com/t/james-webb-space-telescope-general-discussion-thread/956624/151 "2022-01-04T18:48:32Z")
If I understood a NASA representative the mirrors are adjustable. Not just their angle to the secondary mirror but the mirrors themselves. If there’s some optical issue like they had with the Hubble they will be able to correct it. Somewhere out there is a cosmic eye chart. ---
**Author:** ![peccavi](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/peccavi/32/388_2.png) [@peccavi](https://boards.straightdope.com/u/peccavi)\ **Post date:** [January 4, 2022, 7:22pm UTC](https://boards.straightdope.com/t/james-webb-space-telescope-general-discussion-thread/956624/152 "2022-01-04T19:22:58Z")
Based on what I know about the spacecraft, once the sun shield is fully deployed my worry level will drop dramatically. The sunshield deployment has never been demonstrated in space, and the potential for small problems with the deployment to create heat leaks is large. The other deployments are intricate and critical, but all are built around deployment technology that has been proven in flight (actuation, sequencing, control). ---
**Author:** ![wolfpup](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/wolfpup/32/10618_2.png) [@wolfpup](https://boards.straightdope.com/u/wolfpup)\ **Post date:** [January 4, 2022, 7:59pm UTC](https://boards.straightdope.com/t/james-webb-space-telescope-general-discussion-thread/956624/153 "2022-01-04T19:59:03Z")
> [@N9IWP](#): > > I wonder if some, while bad, would not be mission ending. If one of the two main mirror assemblies didn’t fold out, there would still be a lot of mirror segments available. It is, in fact, the upcoming deployment of the secondary mirror that is obviously absolutely crucial. Its function is to reflect the light gathered by the primary mirror back down to the instrument package at its base. Without the secondary mirror, the telescope is completely useless. For that reason, I bet the deployment mechanism is exceptionally robust, probably with redundancies. It also looks relatively simple. ---
**Author:** ![Gorsnak](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gorsnak/32/7587_2.png) [@Gorsnak](https://boards.straightdope.com/u/Gorsnak)\ **Post date:** [January 4, 2022, 8:39pm UTC](https://boards.straightdope.com/t/james-webb-space-telescope-general-discussion-thread/956624/154 "2022-01-04T20:39:16Z")
The sun shield deployment is complete. Remaining steps are secondary mirror deployment, deployment of a radiator, folding out the wings of the primary mirror, and aligning the primary mirror elements. Oh, and the L2 insertion burn. ---
**Author:** ![abcdefghij](https://avatars.discourse-cdn.com/v4/letter/a/43a26b/32.png) [@abcdefghij](https://boards.straightdope.com/u/abcdefghij)\ **Post date:** [January 4, 2022, 8:46pm UTC](https://boards.straightdope.com/t/james-webb-space-telescope-general-discussion-thread/956624/155 "2022-01-04T20:46:03Z")
> [@Magiver](#): > > If there’s some optical issue like they had with the Hubble they will be able to correct it. Somewhere out there is a cosmic eye chart. Better like this or better like this? ---
**Author:** ![wolfpup](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/wolfpup/32/10618_2.png) [@wolfpup](https://boards.straightdope.com/u/wolfpup)\ **Post date:** [January 4, 2022, 9:24pm UTC](https://boards.straightdope.com/t/james-webb-space-telescope-general-discussion-thread/956624/156 "2022-01-04T21:24:01Z")
Don’t laugh! When Hubble first went up, it turned out to be unfortunately near-sighted (actually, what it had was a high degree of spherical aberration). The primary mirror had been ground to a high degree of precision, but the wrong shape. The solution was to equip the Hubble with a pair of spectacles – the Corrective Optics Space Telescope Axial Replacement (COSTAR) which exactly corrected the mirror’s deficiency. Yes, the world’s most sophisticated space telescope for the past 30 years has been wearing glasses! ---
**Author:** ![Lancia](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lancia/32/17174_2.png) [@Lancia](https://boards.straightdope.com/u/Lancia)\ **Post date:** [January 5, 2022, 3:51am UTC](https://boards.straightdope.com/t/james-webb-space-telescope-general-discussion-thread/956624/157 "2022-01-05T03:51:26Z")
[An amateur photographer with 53 subscribers on his YouTube channel captured the JWST as it transited Orion.](https://youtu.be/qfKSeGTf0jk) ---
**Author:** ![squeegee](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/squeegee/32/14537_2.png) [@squeegee](https://boards.straightdope.com/u/squeegee)\ **Post date:** [January 5, 2022, 3:57am UTC](https://boards.straightdope.com/t/james-webb-space-telescope-general-discussion-thread/956624/158 "2022-01-05T03:57:23Z")
nm nm ---
**Author:** ![Lancia](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lancia/32/17174_2.png) [@Lancia](https://boards.straightdope.com/u/Lancia)\ **Post date:** [January 5, 2022, 4:07am UTC](https://boards.straightdope.com/t/james-webb-space-telescope-general-discussion-thread/956624/159 "2022-01-05T04:07:58Z")
[Also check out this video of JWST being released from its launch vehicle and subsequent deployment of its solar panels.](https://youtu.be/2tnpVkK62oo) With Blue Danube as mood music, of course. Apologies if these vids have already been posted. ---
**Author:** ![squeegee](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/squeegee/32/14537_2.png) [@squeegee](https://boards.straightdope.com/u/squeegee)\ **Post date:** [January 5, 2022, 4:10am UTC](https://boards.straightdope.com/t/james-webb-space-telescope-general-discussion-thread/956624/160 "2022-01-05T04:10:58Z")
> [@Lancia](#): > > [Also check out this video of JWST being released from its launch vehicle and subsequent deployment of its solar panels.](https://youtu.be/2tnpVkK62oo) With Blue Danube as mood music, of course. Excellent 🙏 [Previous page](https://boards.straightdope.com/t/james-webb-space-telescope-general-discussion-thread/956624.md?page=7) [Next page](https://boards.straightdope.com/t/james-webb-space-telescope-general-discussion-thread/956624.md?page=9)