Photon fantastic: James Webb Space Telescope spies its first starlight The first photons of starlight have travelled through the James Webb Space Telescope (JWST) and been detected by the Near Infrared Camera (NIRCam) instrument. This is a milestone, albeit not yet the imagery expected once the alignment and commissioning of the observatory and its payloads is complete. It marks the transition of …
I would go : Try to sleep in a tent between x-mas and new year in mountain, on snow...
But I'm biased since I've done it, and despite having a nice -20°C graded sleeping bag the night was not a good one. But that was a time when I was a masochist ( and also somewhat a sadist, since I spread around my misery to the climbing club people that were willing to join ) when it came to winter mountaineering.
One winter, we had cold enough that our camping gas source froze... so making breakfast involved tucking said frozen camping gas sources in the sleeping bag with us on top for half an hour to get them unfrozen enough to prepare a breakfast. In Central France [Sancy Massif], which is not really high mountains.
Note: standard Camping Gaz bottles freeze at -32°C at that time... so obviously at some point the cold went below that during the nitght, we didn't think it would freeze, so we left them outside.
( since then the equipment has evolved a lot and this kind of thing does not happen ( well cannot happen ) except in extreme winter arctic conditions )
I've done that in a couple places over several days. My spouse did NOT steal the duvet, we didn't bring one ... but we did have two appropriate sleeping bags zipped together to share body heat. Quite cozy, actually. Sierras at around 10,000 feet, cross-country ski camping in Yosemite's back country. The dawgs stayed home for that one.
It's all in the equipment.
"If they hadn't, they'd probably have tried to climb into the sleeping bags too"
In that kind of weather? They'd have wanted to be carried in in their sleeping bags ... and then be placed, bag and all, into our bags. Not a lot of insulation on our primary breeds of choice.
No, those aren't part of our pack ... but the pose is identical.
Three or four whippets in a greyhound's bag is common around here ... funnier is one of the greys attempting to fit into a whippie bag. Lazy-arsed comfort loving heat seekers, the lot of 'em.
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Nasa have been doing a PR program for a few years of naming sites and missions after underappreciated former staff. Generally the first black / women / minority staff member who, given Nasa's history, were probably in fairly minor roles at the time.
Oddly Sturmbannführer Von Braun doesn't seem to be getting much prominence.
Famously Sagan objected to Apple using 'Carl Sagan' for the codename for one of its computers (the Power Mac 7100; I had one. Great machine. Butt-ugly, but incredibly powerful.) Carl sued. Apple changed the codename to BHA, for Butt Head (or Hole...) Astronomer. Carl sued again. https://www.engadget.com/2014-02-26-when-carl-sagan-sued-apple-twice.html
Sagan already has an asteroid (https://en.wikipedia.org/wiki/2709_Sagan), a planet walk (https://www.atlasobscura.com/places/sagan-planet-walk), a unit of measurement (the Sagan Unit is a large number, at least 4 billion), a science collaboration web platform (https://en.wikipedia.org/wiki/SAGANet), a crater on Mars (https://en.wikipedia.org/wiki/Sagan_(crater) ), and a weed strain (https://www.leafly.com/strains/carl-sagan).
He would likely have been proudest of the asteroid and the crater, but happiest about the weed.
If the telescope was 4 Democratic Republic of Congos, each segment would be 23 Belgiums and they are trying to adjust their height by about 0.2 Linguine.
Go, slowly and carefully, boffins. Sip your pints.
BTW, the mirror alignment on the Where is Webb only shows the initial mirror alignment after deployment, not the current process.
Main issue is thermal movements, as the telescope points to different targets it will have a slightly different aspect to the sun and the sun-shield effectiveness will change slightly
Plan is to check the mirror and re-align every 2weeks or so. Ideally they will create some sort of model of changes and be able to realign preemptively.
(Not been in this game for nearly 20years, was amazed it has gone so well = never trust space missions)
Indeed
Murphy's law ACTUALLY states "If an aircraft part can be installed 2 ways around and one way is the wrong way, you can guarantee someone will do it"
The surprising part is that even when parts have been explicitly designed NOT to be installed 2 ways around, people have still managed to do it on spacecraft costing billions of dollars
Harvard's law states that "Under rigorously controlled laboratory conditions the device will do what it damned well pleases"
When the colouring is based on specific criteria (e.g. by mathematically shifting the wavelength to a more eye-friendly range), then the images are definitely not a mere "artist's impression". They're as "real" as any other processed photo (and all photos are processed in some way)
Isn't it true though that some of the famous Hubble images were coloured to make them look that bit more impressive, rather than to add scientific value?
>Isn't it true though that some of the famous Hubble images were coloured to make them look that bit more impressive, rather than to add scientific value?
The press release / coffee-table calender shots yes.
BUT the data was still taken in multiple bands for science and is analysed a channel at a time = ie in greyscale.
The colors chosen for to represent each measured band for pretty picture s are chosen to look nice and not necessarily to match the actual wavelengths the data was taken in - so in that sense they are artistic impressions
"Isn't it true though that some of the famous Hubble images were coloured to make them look that bit more impressive, rather than to add scientific value?"
Selling calendars is somewhat different from doing science. I can assure you that no scientific data was harmed during the production of your calendar.
So they wanted an instrument that can detect IR. Nothing wrong with that, right?
How should it display what it found? in IR? so we can't see it?
How about everywhere there was some IR, they show a dot?
Is that "fake"? It's showing real information (where is the IR).
What colour should the dot be?
How about having it depend on the frequency of the IR.
Is that fake? It's showing real information.
Is my TV "fake" because it's showing radio waves as pictures?
What's your point?
Oh no, grey droner is droning here too.
First of all is important to understand some differences between astronomical sensors and commodity camera sensors. First difference.
Almost all commodity cameras have wide-wavelength-range (most of visible, often some IR) sensor with array of filters over it so each pixel gets different filtered set of wavelengths (Bayer sensor: there are some others). As well, for cameras, there will be an IR and possibly UV filter which covers whole sensor so these wavelengths do not get in. Filter array is nice because you can take a picture fast which is important for people who use these cameras. But you lose resolution from the sensor of course, and also you can only use the filters that are glued onto the sensor.
(Some very few commodity cameras have either no colour filters over sensor making for a B/W image, or work in a different (and rather strange) way to make colour images as in Foveon sensor. It is also possible to physically scrape either the IR filter off a sensor or in fact the whole array of colour filters to produce a camera which can see IR or what is effectively a B/W sensor. People do this.)
There is a way around both of these problems if what you are photographing changes rather slowly which astronomical things usually are. You make a sensor which does not have a filter array over it except perhaps filters to remove wavelengths 'off the ends' of the range you care abour. Instead it has in front of it a collection of filters which cover whole image area and which can be changed. Then if you want a colour image you take three exposures (or perhaps more) switching filters. At the end of this you can combine these three images to make one colour image. Each image has full resolution of the sensor so this is much better than a Bayer sensor can do, which is good.
(Of course this is like soup version of what people do with raw files from commodity cameras: these have reasonably raw version of the data from the sensor, which can then be combined into colour image in various ways, or even effectively filtered by removing most/all of data from one channel to produce say red-filtered B/W effect.)
So that is the first difference. Second difference.
Sometimes (as almost always the case with JWST) you do not want to look at visible-light wavelengths are all. So you make the optical system and sensorso it is mostly / entirely sensitive to wavelengths which the human eye can not see at all. So now you still use filters of course to select only some wavelengths of interest or several sets of wavelengths, but if you want to see the image with your eye you can not display it at the original wavelengths. So you now must reconstitute it into visible wavelengths. (Alternatively could evolve to be able to see in IR or UV but this is not very practical: seeing in UV except very near UV has awkward problem of ionising radiation, cancer of eye, death; seeing in IR other than very near IR has awkward problem of low temperature, frozen eye, death. So easier to shift wavelengths to visible on the whole.)
So when you or any human looks at these images they are seeing 'false colour' because otherwise you could not see them at all.
That is second difference. One more difference.
Sometimes, even when you are looking in visible light, you do not want to pick wavelength ranges which correspond to how some apes' eyes have evolved around a particular boring star. Instead maybe you want to look only at a very narrow range of wavelengths in the blue or something, where the thing you are interested in happens. Often you use things called 'grisms' for this which are effectively very fierce filters made using diffraction grating and prism. If you want to see these images then it is necessarily the case that they will not look like anything you would normally see because the filter is not like anything your eye can do. Again, such images are 'false colour'.
The most important thing about all this is that these sensors are designed to produce data which is scientifically useful and only secondarily visually interesting. This is entirely different than purpose of commodity camera. It would be perfectly possible to launch commodity camera into space (like on Ingenuity, for instance, or the parachute cameras on Perseverance), but the results from these would be absurdly astronomically limited because commodity camera is designed only to make an image which corresponds to what the eyes of some apes see and those apes did not evolve to be able to see many interesting things.
What astronomers need is the rawest possible data from the sensor combined with very flexible filtering (which must be done before the sensor but should be done in such a way as to not throw away sensitivity or resolution where possible), which covers the wavelengths they care about. This is what astronomical sensors & optical systems do. If they do pretty as well, that is good: if not, fine.
In fact NIRCam does even better than this: each unit (there are two which image areas next to each other) has dichroic beamsplitter which splits incoming light into long & short wavelength beams. Then there are two sensors (per unit), one for long, one for short wavelengths, and each of these sensors has its own set of filters. As well as all this there is wavefront-sensing stuff which is needed for mirror alignment as going on now. You can see a picture of it all here.
I do exactly the opposite, to support ElReg. I whitelist theregister{.co.uk,.com} on my adblockers.
You think these guys can work for free?
Further, I actively enrich/beneficiate/inflate the $/unit Premium on that income stream, by gaming the now-toxic market practices of the online ad networks: I periodically make a point of clicking lots of their ads.*
This lifts their click-thru rate. Which I believe is a key driver/multiplier of their ad-spaces' $$ value on the behind-the-scenes auction exchanges. So not only are they getting money for the volume of ads served, but they earn more per ad. Double-dipping. At no cost to myself bar some seconds of my time.
I realise this is gaming the system. But the system's players have been proactively gaming users and websites for some time; eg, the networks by hijacking revenue, the advertisers by jamming shit-tons of pointless machine-jamming badly-coded JavaScript into their ads.
I am quite happy to render unto Caesar that which is Caesar's.
.
* Ctrl-Click all of them in a fast sweep: they open in background tabs while I get on with reading uninterrupted; when they've finished loading, I close the tabs to flush the usually toxic JavaScript they've all excitedly rammed into my ram. Rinse&Repeat on each article.
Net skin off my nose: 0.
Net benefit to ElReg: $positive.
If enough of us did this, maybe ElReg could afford to rent Dabbsie an actual office.
Would you accept a reverse charge phone call if you knew it was just some marketer?
Would you pay two quid a time to receive a non franked letter if you knew it was just an ad flyer?
So why are you happy to spaff your data allowance and / or credit, paying to receive marketing crap?
Once again, internet marketing is theft.
Buy yes,every so often I have a session of ctrl-clicking to background open a good few ads, so long as I'm on a non metered connection.
Would you accept a reverse charge phone call if you knew it was just some marketer?
Perhaps yes, if it came with 300 minutes of free calls.
Would you pay two quid a time to receive a non franked letter if you knew it was just an ad flyer?
Perhaps yes, if it came with 100 first class stamps.
So why are you happy to spaff your data allowance and / or credit, paying to receive marketing crap?
See above: there may be benefits which countervail the costs. Also there may not be: but the choice is not what you make it out to be.
(Note: I do not work for internet advertisers at all do not have anything to do with any of them.)
"So how do you think The Register exists?"
I'm fairly certain I provided more profit for ElReg at the Cash&Carrion store (before it went TITSUP[0] back in 2008) that you'll ever provide them doing the pointy-clicky dance for shit you have absolutely no need for, much less any interest in.
"I am sure you are good socialist?"
Me? A socialist? That's a laugh. Sorry to burst your bubble, but I'm one of the vast majority of normal people who don't identify with any particular religion political bent.
[0] Totally Incapable of Transferring Selected User Packages
Of course it is over time and over budget, the whole project fell well within the realm of Cheops' Law.
Technically, there's an infinitesimal chance that the mirrors are already optimally aligned by sheer chance. Unlikely, admittedly, but if we launched trillions of similar telescopes, some of them would be aligned already and save us having to align the rest.
Probably be a bit of a waste of resource though...
At long last we will have confirmation that, instead of being able to observe the remnants of big bang, we will be shown images that will confirm the universe stretches out to the limits of the JWST vision, exactly as we all see it at night from here on planet Earth.
That would be an extraordinary finding. Especially since we have been able to see the remnant radiation from the big bang for 60 years (and you can do this almost at home if you want to). And also very surprising since we already can see very distant (early) galaxies and they are pretty different than nearby (late) ones which makes no sense at all in a steady-state universe. Indeed you can see this just by looking at Hubble UDF image.
So if it found this it would directly contradict very well-tested existing observations. Perhaps this is because aliens have been injecting alternate facts into our telescopes all this while. Yes, probably that is it.
ESA has posted this image to Flickr:
https://www.flickr.com/photos/europeanspaceagency/51874544307/in/dateposted/
Caption reads:
"Webb primary mirror selfie
This “selfie” of the James Webb Space Telescope primary mirror was created using a specialised pupil imaging lens inside of the NIRCam instrument that was designed to take images of the primary mirror segments instead of images of space. This configuration is not used during scientific operations and is used strictly for engineering and alignment purposes. In this case, the bright segment was pointed at a bright star, while the others aren’t currently in the same alignment. This image gave an early indication of the primary mirror alignment to the instrument.
Credits: NASA"
Other images from ESA in their Flickr feed show how each sub-mirror images a star and when the mirrors are all aligned properly, and their individual curvatures corrected, should produce a single dot, rather than the multitude of blurred images currently visible. Its going to take a while, but hopefully it will be worth it.
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