Yet Another Cycling Forum
Off Topic => The Pub => Topic started by: quixoticgeek on 25 December, 2021, 10:50:28 am
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Happy Telescope Launch Day everyone!
Who's gonna watch the launch?
J
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Already on it. :thumbsup:
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Me too.
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Me too. Just now they're warbling about stuff anyone who's interested will already know.
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Bah! My time calculation is one hour out. At least I haven't missed anything.
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Which streams are people watching?
I'm on:
https://youtu.be/5rARTOhbLDg
J
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I’ll be having a look in shortly. Son-in-law bought a telescope for Ms Beardy the elder which made her very happy. I’m a little jealous, especially as she lives on the edge of Dartmoor which is a protected night sky.
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Just nine minutes to launch now.
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Have switched to this stream now:
https://youtu.be/7nT7JGZMbtM
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Which streams are people watching?
I'm on:
https://youtu.be/5rARTOhbLDg
J
This one. (https://youtu.be/nA9UZF-SZoQ)
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Woo hoo :thumbsup:
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Lift off!
J
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ob-xkcd: https://xkcd.com/2559/
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Switched off the stream when some nasa administrator started some sort of christian sermon...
This is space science, why are they bringing Christianity into it?
Anyway, was a good launch!
I think Nancy-Grace-Roman telescope is the next up, which will be in no more than 6 years.
J
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The roast duck was going critical and I was deep-frying prawns when the count hit zero, so I missed it.
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Jehovah's Witness Space Telescope? :o
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The next dodgy moment is when they start to unfold it. I suspect there we’ll be a fair few fingers crossed when they press that button.
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I think I've inspired both my children and our three nephews by the wonders of the universe and the enormity and significance of JWST with the result that we all sat and watched it lift off.
Little Miss hatler, who up to now hasn't been too enamoured of things scientific is blown away by the whole enterprise and is sending links to the lift off to her mates.
There's hope for the future !!
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Did I read that there are 237 single points of failure in getting this thing up and running ?
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This is good: Deployment sequence https://www.youtube.com/watch?v=RzGLKQ7_KZQ&t=107s
Does show that there is a lot that still needs to go well...
JWST orbit lagrange points info is interesting... https://webb.nasa.gov/content/about/orbit.html
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Did I read that there are 237 single points of failure in getting this thing up and running ?
307 single points if failure, out of a total of 344 moving parts.
J
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If astronomer and SCIENCE writer Tom Kerss gets a look at his BBC interview on the subj. from the viewers' perspective he's gonna be fummin' when he sees the caption describing him as an astrologer.
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Between days three and seven, Webb will deploy the parts of its sunshield, raise the tower assembly and deploy the momentum flap. Day 10 might be the most nail-biting, as Webb hoists its secondary mirror into position. Heidi Hammel, a scientist on the mission, said:
For me, personally, that’s the scariest part of the whole deployment sequence, the secondary mirror … If we don’t have a secondary mirror, we don’t get any light from space into our cameras and spectrographs. There’s nothing.
https://earthsky.org/space/james-webb-space-telescope-30-days-of-terror/
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The secondary mirror deployment mechanism looks as if it uses quite robust hinges & joints, so I wouldn't worry too much. It's the sunshade that looks like the real nail-biter, given that an earlier test tore one.
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The secondary mirror deployment mechanism looks as if it uses quite robust hinges & joints, so I wouldn't worry too much. It's the sunshade that looks like the real nail-biter, given that an earlier test tore one.
Yep, that's the thing that's scaring me.
J
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And there’s a lot of it for something to go wrong. It’s not as if they had the luxury of designing in redundancy given the payload restrictions.
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Scope for unpredictable failure conditions too with an Xmas day launch:
(https://imgs.xkcd.com/comics/december_25th_launch.png)
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JWST status page:
https://www.jwst.nasa.gov/content/webbLaunch/whereIsWebb.html
And this bit for fun:
https://en.wikipedia.org/wiki/Halo_orbit
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(https://pbs.twimg.com/media/FHocebGUYAMHFFw?format=jpg&name=small)
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^ :thumbsup:
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I have an ESA branded "remove before launch" tag I was given by one of the ground control crew from the ISS.
The space stuff all has before launch, not before flight...
J
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(https://pbs.twimg.com/media/FHsVnYPWQAITidP?format=jpg&name=large)
(https://pbs.twimg.com/media/FHsVjhNWYAE0OSc?format=jpg&name=large)
J
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Looks like sunshield deployment has been at least partially successful: the status page is showing large temperature differences between cold & hot sides.
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And that's before the sunshield is fully deployed. They're still folded up and not due to be stretched out in place until Day 6, and then fully tensioned on Day 7.
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JWST status page:
https://www.jwst.nasa.gov/content/webbLaunch/whereIsWebb.html
For sensible units: https://www.jwst.nasa.gov/content/webbLaunch/whereIsWebb.html?units=metric
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JWST status page:
https://www.jwst.nasa.gov/content/webbLaunch/whereIsWebb.html
For sensible units: https://www.jwst.nasa.gov/content/webbLaunch/whereIsWebb.html?units=metric
...with improbable accuracies ::-)
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Beyond the moon, -150 deg C, and cruising at 2,000mph. That's worse than the BCM audax.
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(https://pbs.twimg.com/media/FHsVnYPWQAITidP?format=jpg&name=large)
(https://pbs.twimg.com/media/FHsVjhNWYAE0OSc?format=jpg&name=large)
J
So cool.
I want.
It makes my 'Remove before flight' tags pale into insignificance.
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JWST status page:
https://www.jwst.nasa.gov/content/webbLaunch/whereIsWebb.html
For sensible units: https://www.jwst.nasa.gov/content/webbLaunch/whereIsWebb.html?units=metric
...with improbable accuracies ::-)
I bet the sensors are reading in Celsius/Kelvin and it's being converted from degrees SCIENCE to degrees Frankenstein and back.
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JWST status page:
https://www.jwst.nasa.gov/content/webbLaunch/whereIsWebb.html
For sensible units: https://www.jwst.nasa.gov/content/webbLaunch/whereIsWebb.html?units=metric
...with improbable accuracies ::-)
I bet the sensors are reading in Celsius/Kelvin and it's being converted from degrees SCIENCE to degrees Frankenstein and back.
Probably mV, mA or something like that.
It just bugged me that the temperatures were quoted in integer degF (but to two DP ::-)) then converted to degC with the same 2DP.
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I squinted at the page source to see if it was doing the conversion in the browser, and now I wish I hadn't.
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It is 389k miles away now, and some kind of little separation tower is deployed.
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Sunshield covers released.
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JWST is now expected to have a 10+ year lifespan (https://blogs.nasa.gov/webb/2021/12/29/nasa-says-webbs-excess-fuel-likely-to-extend-its-lifetime-expectations/) due to the precision of the Arianespace Ariane 5 launch, which exceeded the requirements needed to put Webb on the right path.
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JWST is now expected to have a 10+ year lifespan (https://blogs.nasa.gov/webb/2021/12/29/nasa-says-webbs-excess-fuel-likely-to-extend-its-lifetime-expectations/) due to the precision of the Arianespace Ariane 5 launch, which exceeded the requirements needed to put Webb on the right path.
This is excellent news. I'm still holding out hope that they come up with a robotic refueling mission.
J
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Does anyone know why the sunshield tensioning has been re-scheduled ?
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https://www.space.com/james-webb-space-telescope-sunshield-tension-delay
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Aha ! Thank you.
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I bet the sensors are reading in Celsius/Kelvin and it's being converted from degrees SCIENCE to degrees Frankenstein and back.
TIL: according to that website, the opposite of "Metric" is "English" :facepalm:
TI actually L: I was wondering whether it was getting a bit crowded at the L2 "point" and how big a point it actually is, but it turns out that the various telescopes do not just orbit the sun but also orbit the L2 point. How they orbit something that's not actually there and so doesn't have any gravity is some kind of magic to do with gravitational wells or something.
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"English" seems a sensible term in that context. They don't want to use "Imperial" because they're American (and if they gave measurements of volume or weight, "Imperial" would be incorrect anyway), and they don't want to use "US customary measures" because they're aware that they have an international audience. But the three countries which don't officially use metric measures all speak English to some degree, and the vast majority of people choosing to see miles and fahrenheit will be English speakers.
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Apropos to the above; I was recent;h looking at a British canal route finder on the interwebs and all the distances were giving in miles and furlongs. I had heard that the canals were a bastion of gammons, but the more research I do into thE possibility of obtaining g a live aboard the less I feel like doing so because my potential neighbours are going to be racing ranting gibbonous gammons.
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Might it be that canals were originally built in miles and furlongs and have never really been surveyed since? Just as railways still use miles and chains cos that's what the Victorian engineers used and the cost of resurveying (simply converting would introduce all sorts of errors) isn't worth it? Similar rules apply to cricket, horse racing and whatever...
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Apropos to the above; I was recent;h looking at a British canal route finder on the interwebs and all the distances were giving in miles and furlongs. I had heard that the canals were a bastion of gammons, but the more research I do into thE possibility of obtaining g a live aboard the less I feel like doing so because my potential neighbours are going to be racing ranting gibbonous gammons.
The reason for that is because all the bridge and tunnel markings will be in chains, furlongs and miles. Just historical, no gammon conspiracy.
There are a fair number of bigoted old gits to be found on the waterways, but also a lot of hippy types and lots of other sorts too. Don't be put off by the minority that post loudly on canal forums. If you want to discuss practicalities start a new thread - I'm moving on to my new boat tomorrow after a gap of over 20 years.
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TI actually L: I was wondering whether it was getting a bit crowded at the L2 "point" and how big a point it actually is, but it turns out that the various telescopes do not just orbit the sun but also orbit the L2 point. How they orbit something that's not actually there and so doesn't have any gravity is some kind of magic to do with gravitational wells or something.
They're only not there in the sense that a hilltop isn't there: Think of gravity like a contour map, with the Earth and Sun as holes of appropriate depth. L1, L2 and L3 are 'saddles'[1], and L4 and L5 are ridges. If you place an object near L1, L2 or L3 it will tend to drift away, but if you put it in orbit around the point, you can keep it there with the occasional burst of thrust. That's why the JWST's lifetime is limited by its fuel supply; eventually it will run out and go wandering off into heliocentric orbit.
You'd expect the same to be true of L4 and L5, but it turns out the contour map is rotating (I dunno, it's in the hands of a car passenger who's a frequent perpetrator of terms like "other left" or something), and inertia pulls it back into place.
(https://upload.wikimedia.org/wikipedia/commons/d/d0/Lagrangian_points_equipotential.gif)
[1] In the horse rather than bicycle sense.
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Huzzah !! Sunshield deployment complete.
I would think that the engineers were more concerned about this stage than any of the others.
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I bet the sensors are reading in Celsius/Kelvin and it's being converted from degrees SCIENCE to degrees Frankenstein and back.
TIL: according to that website, the opposite of "Metric" is "English" :facepalm:
TI actually L: I was wondering whether it was getting a bit crowded at the L2 "point" and how big a point it actually is, but it turns out that the various telescopes do not just orbit the sun but also orbit the L2 point. How they orbit something that's not actually there and so doesn't have any gravity is some kind of magic to do with gravitational wells or something.
Need to allow space for the alien monolith/stargate, too.
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Secondary mirror appears to have deployed successfully. :thumbsup:
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Huzzah!
Although not previously posting here i am quietly excited about this, if only from a difficulty pov
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Indeed. Great news. Though I have to question this blurb on the update website : -
The secondary mirror plays an important role in reflecting the light from the primary mirror to where the instruments sit, behind the primary mirror.
An important role ?? It's the only thing doing the reflecting.
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And here's a thought. If the side bits of the main mirror fail to deploy then they have at least got two thirds of the main mirror in place, so, barring other possible disasters, they are guaranteed to have a working telescope.
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Indeed. Great news. Though I have to question this blurb on the update website : -
The secondary mirror plays an important role in reflecting the light from the primary mirror to where the instruments sit, behind the primary mirror.
An important role ?? It's the only thing doing the reflecting.
Let's have a think about that.
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Obligatory xkcd (https://xkcd.com/2564) :-D
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JWST status page:
https://www.jwst.nasa.gov/content/webbLaunch/whereIsWebb.html
For sensible units: https://www.jwst.nasa.gov/content/webbLaunch/whereIsWebb.html?units=metric
...with improbable accuracies ::-)
I bet the sensors are reading in Celsius/Kelvin and it's being converted from degrees SCIENCE to degrees Frankenstein and back.
Probably mV, mA or something like that.
It just bugged me that the temperatures were quoted in integer degF (but to two DP ::-)) then converted to degC with the same 2DP.
They have now changed both Celsius and arcane to the nearest whole number. They also admit that the temperatures are only updated daily, as they don't expect fast changes.
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Nasa engineers complete the unfolding of the James Webb space telescope (https://www.theguardian.com/science/2022/jan/08/nasa-engineers-complete-the-unfolding-of-the-james-webb-space-telescope)
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\o/ for space origami
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Now, if it hadn't all unfurled:
'Oh what a tangled Webb we wove'
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https://www.jwst.nasa.gov/content/webbLaunch/whereIsWebb.html?units=metric
Now 1.5 million km away and 95% of the way there.
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https://webb.nasa.gov/content/webbLaunch/whereIsWebb.html?units=metric (https://webb.nasa.gov/content/webbLaunch/whereIsWebb.html?units=metric)
100%
Next step - orbital insertion burn. In about 28 minutes.
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Now in orbit and -210C on cold side
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(https://www.nasa.gov/sites/default/files/thumbnails/image/telescope_alignment_evaluation_image_labeled.png) (https://www.nasa.gov/press-release/nasa-s-webb-reaches-alignment-milestone-optics-working-successfully)
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Worth watching Dr Becky talk about this, just for her infectious joy.
https://youtu.be/mpE8ttCEd-w (https://youtu.be/mpE8ttCEd-w)
Something to cheer you up on a grey day.
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Worth watching Dr Becky talk about this, just for her infectious joy.
https://youtu.be/mpE8ttCEd-w (https://youtu.be/mpE8ttCEd-w)
Something to cheer you up on a grey day.
That video seemed to be about women's pay. Very important topic but not what I was expecting!
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Worth watching Dr Becky talk about this, just for her infectious joy.
https://youtu.be/mpE8ttCEd-w (https://youtu.be/mpE8ttCEd-w)
Something to cheer you up on a grey day.
That video seemed to be about women's pay. Very important topic but not what I was expecting!
WTF is happening with youtube? I copied the URL by right-clicking on the vid as usual
Try this one
https://youtu.be/1nOX66G5q9E (https://youtu.be/1nOX66G5q9E)
Oh my, Dr Becky responded to a question I had about the data. <swoon>
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First images from Nasa’s James Webb space telescope reveal ancient galaxies (https://www.theguardian.com/science/2022/jul/11/nasa-james-webb-telescope-ancient-galaxy-images)
(https://i.guim.co.uk/img/media/60f8262ffcf0949c3c439cbc1ff26e30ac5cdc36/0_0_4537_4630/master/4537.jpg?width=1020&quality=85&fit=max&s=c8abb0b5a371966a683846afec8bb5d7)
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The contrast with Hubble of same view tells you how much better it is.
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The best bit about that is the arcs. Those are the images of 13 billion year old galaxies having been 'lensed' through the galactic cluster which is the sharper images.
Mind blowing stuff.
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It's the coolest photo ever.
No seriously, the sensor is at like 6° above absolute zero...
J
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https://www.nasa.gov/webbfirstimages :thumbsup:
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Latest from James Webb Space Telescope
Highest resolution picture of Jupiter ever captured!
#JamesWebbSpaceTelescope #JWST
(https://pbs.twimg.com/media/FXiMsVlaIAAnEdG?format=jpg&name=900x900)
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That would be funnier if they were geese.
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Untitled ones :P
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Look like geese from here.
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The one on the right might be a Canada goose, but the rest are DEFINITELY ducks!
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Last night's Sky at Night was about JWST. Dear Maggie said that the instruments were at a temperature of 7 deg. Kelvin - ouch!
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The one on the right might be a Canada goose, but the rest are DEFINITELY ducks!
Look like Brent Geese to me.