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A giant European telescope rises as U.S. rivals await rescue
- tpmx 3y agohttps://en.wikipedia.org/wiki/Extremely_Large_Telescope https://en.wikipedia.org/wiki/Extremely_Large_Telescope It has around 250 times the light gathering area of the Hubble Space Telescope and, according to the ELT's specifications, would provide images 16 times sharper than those from Hubble. Edit: Wow, this construction image from August: https://upload.wikimedia.org/wikipedia/commons/thumb/7/75/Almost_dome_%28elt-huedepohl-aug2023-drone1%29.jpg/2880px-Almost_dome_%28elt-huedepohl-aug2023-drone1%29.jpg https://upload.wikimedia.org/wikipedia/commons/thumb/7/75/Al...
- nabla9 3y agoExtremely Large Telescope is the budget version. The original plan was Overwhelmingly Large Telescope https://www.eso.org/sci/facilities/eelt/owl/OWL_design.html https://www.eso.org/sci/facilities/eelt/owl/OWL_design.html
- kulahan 3y agoGod I still hope that becomes a thing.
- jacquesm 3y agoSomewhat unlikely: there is a race on between arrays of cheaper telescopes linked by software and ever larger single telescopes and optical bags of tricks to combine the images from multiple smaller telescopes. So an even larger instrument might well be obsolete before it could be constructed and that's before we get into the cost of such a project.
- kulahan 3y agoYeah, and on top of that, making your telescope bigger does not have a linear cost increase. I know it's unlikely, but I can dream!
- jacquesm 3y agoThere are some interesting parametric cost models for telescopes floating around and various papers describing the models (and the data that went into the models).
- Someone 3y agoFrom that page: “Keeping OWL 3264 segments aligned to a few millionths of a millimeter is a daunting but not impossible task” And that’s for a 100m diameter main mirror.
- OldGuyInTheClub 3y ago"The ESO specialists expect resolutions from OWL that are up to 40 times higher than those of the Hubble Space Telescope. If the 100-meter mirror cannot be financed, a 60-meter variant is being planned. The name OWL would remain the same. Because then the project is jokingly called »Once was larger«." https://www.itespresso.de/2006/04/17/groesstes-observatorium-der-welt-pcpro/ https://www.itespresso.de/2006/04/17/groesstes-observatorium... --> Google or other translate
- kitd 3y agoQuestion from a total noob: How modular are these segmented mirrors? Ie, if the budget runs to 'only' 39m now, is it possible to upgrade it to 42m later by adding segments to what's already there?
- manuelmoreale 3y agoI have no special expertise on the subject but by reading and watching about it I think that’s more complex than you might think because there’s a lot a extra systems to make the mirror work with that set up. So it’s not a matter of just bolting in a new ring of hexagonal mirrors and I suspect the majority of the cost comes not from the actual mirrors themselves.
- alfiopuglisi 3y agoThe segments themselves are 100% modular and you could tile an US state with them. The main problem is engineering: the whole thing needs to behave like a single object, turning 360 degrees and moving between horizon and zenith (horizontal and vertical), with a minimum of mechanical flexure. And also resisting wind load. In essence, it's a lightweight building that has to move freely, and this one won't get bigger.
- zzbn00 3y agoThey are modular but not very interchangable (there are 133 different designs of the segments in the primary mirror). Making a much larger mirror would also face another obstacle: the focal length is designed to be practical for a ~40m mirror.
- antognini 3y agoDespite public perception to the contrary, the Hubble Space Telescope is not an especially large telescope. Telescopes on the ground of a similar size are a dime a dozen. What made HST special is that it was in space and could get much higher resolution than ground based telescopes at the time. With modern advances in adaptive optics that advantage has generally been negated, so a telescope needs to have some other reason to be put in space.
- Cthulhu_ 3y agoWasn't it being cold in space so there's more infra red coming in also a factor?
- alfiopuglisi 3y agoMore than temperature, the main problem is the atmosphere. Hubble can see a lot of infrared, and also ultraviolet, because it is in space. Ground-based IR telescopes are somewhat limited, and UV is non-existent.
- bouvin 3y agoFor ground-based telescopes, I am continually impressed with what amateur astronomers construct in their back gardens, e.g., https://youtu.be/tFZVmVRItbg https://youtu.be/tFZVmVRItbg
- throw0101a 3y agoTom Scott did a video on the ELT about a month ago: * https://www.youtube.com/watch?v=QqRREz0iBes https://www.youtube.com/watch?v=QqRREz0iBes Most of the video is an explanation of (a) why ground-based telescopes are still useful, and (b) why ganging up multiple telescopes (to create a large 'virtual' area) only goes so far, and then he gets into the ELT in part three of the video. It's big. The scale is remarkable.
- 7373737373 3y agoI think its total mirror area is more than that of all existing (largest) professional reflecting optical telescopes combined 39.3m aperture, mirror area scales quadratically with that https://en.wikipedia.org/wiki/Extremely_Large_Telescope https://en.wikipedia.org/wiki/Extremely_Large_Telescope https://en.wikipedia.org/wiki/List_of_largest_optical_reflecting_telescopes https://en.wikipedia.org/wiki/List_of_largest_optical_reflec... https://en.wikipedia.org/wiki/List_of_large_optical_telescope https://en.wikipedia.org/wiki/List_of_large_optical_telescop...
- Aeolun 3y agoI love their naming sense. Very Large Telescope Extremely Large Telescope Overwhelmingly Large Telescope
- nicolas314 3y agoRelevant: https://maz.one/insanely-large-machines.html https://maz.one/insanely-large-machines.html
- pvaldes 3y agonext should be called 'Such Telescope' and 'So much Telescope wow'
- layer8 3y agoDefinitely A Telescope
- krawat3 3y agoTom Scott recently posted a great, 30-minute video about this telescope. Highly recommended. https://www.youtube.com/watch?v=QqRREz0iBes https://www.youtube.com/watch?v=QqRREz0iBes
- brucethemoose2 3y ago> likely to be more than $100 million annually Oof. Should the US have just partnered with Europe? Seems like a bigger telescope would have been better than two individual projects (with one struggling significantly).
- deleted 3y ago[deleted]
- adventured 3y agoThere might be enough use demand to saturate multiple gigantic telescopes. The US should fund at least one as well.
- brucethemoose2 3y agoTechnically a bigger telescope has more throughput, right? It can expose the same spot for less time, then move onto the next observation.
- antognini 3y agoGenerally there is a lower bound because it takes a few minutes to slew to a new spot on the sky and stabilize. Very large telescopes are slower, so this will take longer, possibly 5--10 minutes. So you typically want to spend at least 20 minutes per target so that most of your time is spent observing rather than slewing. That's why there's still a lot of demand for 1-m class telescopes. There are also issues with saturation. Large telescopes simply cannot observe brighter targets because they saturate the detectors too quickly. (This is not so much of a problem for deep field objects since none of them have high surface brightness anyway, but can be a problem for brighter stars.)
- db48x 3y agoOnly if it were completely automated, or run by the full–time staff instead of by visiting astronomers. Plus, even if a new telescope is 10× better than the old one, nobody will agree to observe for 1/10th the time; it would negate the advantage of the new scope.
- Dalewyn 3y ago[flagged]
- krisoft 3y agoThere is nothing clickbait about the title. It describes accurately and succintly what the article writes. “A giant European telescope rises as U.S. rivals await rescue” is exactly what the article writes about. There is a giant European telescope under construction while the US telescopes under construction of comparable size have an uncertain future especially if the NSF funding does not happen.
- Dalewyn 3y agoIt costs them nothing to directly name the "giant European telescope" and which US telescopes "await rescue". It costs me time and makes them clickbait monies (the latter is the important part) if the title is non-descript (read: clickbait) and I have to open the damn link to figure out WTF the headline is talking about (read: baiting me and reeling me in). I should be compelled to click into an article because the headline genuinely interests me, not because it refuses to tell me WTF it's talking about unless I get reeled in.
- krisoft 3y ago> It costs them nothing to directly name the "giant European telescope" and which US telescopes "await rescue". Have you thought about how “giant European telescope” and “US rivals” are more descriptive than ELT and GMT/TMT? Especially to people who are not already well informed about the arcana of under-construction future telescopes. > not because it refuses to tell me WTF it's talking about unless I get reeled in Idk. You keep using that three letter abreviation of a swear. Is that also very emotionally charged in your usage? Because to me it seems you are very angry over what to me appears a mild editorial disagreement. They haven’t tried to kill your puppies, they are not trying to scam you out of your retirement savings, they just wrote a descriptive title to the best of their abilities. If I am missreading the emotional content of your comment then I am sorry. If I am not then I’m sending you a bunch of good vibes. Either way, hope you will have a lovely day.
- dylan604 3y agoRecently there was a video link posted here about the process of aligning the JWST's 18 mirror segments that shed light on the complexity. The task looked challenging at 18, but it goes to mind boggling at 798 segments of the ELT primary mirror. The level of impressiveness is astronomical.
- antognini 3y agoBeing on the ground makes the task both easier and harder. It's easier because unlike JWST they don't have just one chance to get it right. If something goes wrong, they can just fix it. But it's also a more challenging problem to solve because the Earth's gravity deforms the mirrors, and each segment gets deformed differently, and each segment, in turn, gets deformed differently when the mirror is pointed in different directions. So you have to have an extremely accurate model of the deformation as a function of orientation.
- fnordpiglet 3y agoThese sums of money are so pathetically small. We routinely drop similar sums on seemingly random stuff, none of which ever returns even a small amount of awesome.
- renewiltord 3y agoI'm sure they will accept more money for the same thing, if you'd like. I live in San Francisco, where locals constantly complained that there wasn't enough funding for essential things. As a result, we funded the things and it turns out that if you want to buy a thing that costs X, the person selling it to you will happily accept 10X if you want to spend that much on it.
- reaperman 3y agoI don't think the only possible takeaway should be “whatever the project is, you’ll always get the same result no matter how much or how little you spend”. That seems fallacious. I think there were other forces at work in the SF allegory, that probably don't apply to all projects.
- robertlagrant 3y agoI don't think that was the proposition.
- reaperman 3y agoWhat do you think it was?
- robertlagrant 3y agoSpending more doesn't guarantee a better result. You misinterpreted that as spending more never gives a better result.
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- ngcc_hk 3y agoAdjust both for those low orbit satellite plus gravity. But I think it is great to have some around. If nothing else, let us not discovery end day asteroid days before it arrived.
- nologic01 3y agoThese giant facilities are in a sense humanity's artificial "exo-sensors", an augmentation of our ability to perceive and understand the Universe. They are costly in comparison to resources accessible to an indvidual but still manageable when done collectively by large countries or country coalitions. Its not clear when and how competition can be a plus in this space. If the core technology is similar/known it may make sense to just pool the widest possible international resources and build the largest possible thing. But there is also something to be said about competing teams taking calculated risks with exploring new directions.
- euroderf 3y ago> humanity's artificial "exo-sensors", an augmentation of our ability to perceive and understand the Universe Indeed. McLuhanesque Extensions of Man.
- denton-scratch 3y ago> Next month, the first batch of polished mirror segments should set off from France by ship in a temperature-controlled container. Why do they need a temperature-controlled container for shipping? I would have expected that temperature control would only be needed once they're deployed and in service.
- agent327 3y agoYou want to avoid condensation (and other depositions) on the mirror surface. That is most easily avoided if the mirror is slightly warmer than the environment. Of course the container is sealed as well, but there's always some moisture in the air anyway, and it's worthwhile protecting the mirrors from that.
- input_sh 3y agoMirrors deform under temperature changes, and the precision target is measured in tenths of nanometers.