26 ms·

I'm a little embarrassed to say this and I don't know exactly what I pictured in my head, but I had no idea these telescopes were so big[1]. I guess I never sa

• zionic 5y ago
  Really sad that 30 years later we're only slightly larger. This is a major problem for telescopes since there are hard physical limits on resolution vs size.
  • jxcl 5y ago
    They both look like they might be similar sizes in an illustration like that, but the Hubble mirror is 2.4 meters, whereas the JWST mirror is 6.5 meters, which has 7 times the light-gathering capability of Hubble.
  • jon_richards 5y ago
    Obviously it’s sad that we don’t have a larger Hubble-equivalent by now, but the Webb’s operating temperature makes it a completely different beast. It is massively expanding our capabilities in a way a larger Hubble wouldn’t. And I’m hopeful for the mid-term future, as the massive improvements in launch capability we’re seeing start to pay off.
  • zelos 5y ago
    It's 2.5 times the mirror diameter, which is 6.25 times the light collecting area.
  • p1mrx 5y ago
    SpaceX Starship may help with that, assuming it works as intended.
• inamberclad 5y ago
  The space shuttle blows my mind every time I see one. It's huge - the size of an airliner - and would glide back at Mach 25. It's a humbling level of accomplishment.
  • vermontdevil 5y ago
    To show the comparison (737 for example here) https://icdn2.digitaltrends.com/image/shuttle-948x1500.jpg?ver=1 https://icdn2.digitaltrends.com/image/shuttle-948x1500.jpg?v...
    • titzer 5y ago
      Those size comparisons are super misleading. I've seen the shuttle and it's not that big. A 737 is pretty small. The shuttle can ride piggy-back on a 747--in fact it was designed to: https://www.nasa.gov/centers/armstrong/news/FactSheets/FS-013-DFRC.html https://www.nasa.gov/centers/armstrong/news/FactSheets/FS-01... Also, the comparison with the Statue of Liberty is also misleading. The Statue of Liberty is on a huge pedestal that makes it stand much, much higher; the orbiter and boosters wouldn't reach the top of the SoL.
      • lucideer 5y ago
        The sum of your comment seems to be the subjective belief that the statue of liberty and 737s are "not that big"... Not sure what size you'd expect the shuttles to be, but being in the same ballpark as the statue of liberty (without pedestal) seems a great deal larger than my expectations.
        • titzer 5y ago
          These are subjective things, sure. My personal feeling upon seeing the shuttle was that it was not that big, because I've seen big airliners all my life. I was expecting the shuttle to be bigger. So when I looked at the parent's infographic and saw a 737 and the Statue of Liberty there, they didn't seem right (I've also seen the SoL in-person). So the size comparisons I think are quite misleading in that graphic, and yeah, I was surprised how much smaller the shuttle is than what I expected.
• sgt101 5y ago
  The JWST at 6.5m is larger than the largest terrestrial telescope in my childhood. Keck was the first one bigger - 1989. The next one Keck 2 was 1997. https://en.wikipedia.org/wiki/List_of_largest_optical_reflecting_telescopes https://en.wikipedia.org/wiki/List_of_largest_optical_reflec...
• readthenotes1 5y ago
  The human is not to scale if that's the Webb telescope.
  • sandworm101 5y ago
    I think the height is there, but the human seems otherwise out of proportion. He seems to wide, which gives the illusion that he is shorter. And his head is too big, which again makes him look younger/smaller, more cartoonish. I think this is from a stock cartoon character rather than a real person.
  • danbruc 5y ago
    I measured the mirror - top to bottom - as 304 pixels and the human as 86 pixels. This makes the human 1.83 meters given a mirror diameter of 6.5 meters. So it is to scale.
  • anon_123g987 5y ago
    A human standing next to a full-size replica: https://external-content.duckduckgo.com/iu/?u=https%3A%2F%2Flive.staticflickr.com%2F139%2F324603326_69bc62e0c9_b.jpg&f=1&nofb=1 https://external-content.duckduckgo.com/iu/?u=https%3A%2F%2F... It looks the same to me.
    • pseudolus 5y ago
      Where is this replica located? Is it open to the public?
      • anon_123g987 5y ago
        I don't know where it is currently, but according to this 2008 article it was on a world tour at that time. https://phys.org/news/2008-07-james-webb-space-telescope-full-scale.html https://phys.org/news/2008-07-james-webb-space-telescope-ful...
      • asoneth 5y ago
        I recall seeing a full-sized mockup of the James Webb at the South by Southwest about ten years ago. It was accompanied by a small traveling exhibit about the mission and some folks from a NASA (or Northrup?) education team to answer questions. They had been taking it to cities and museums across the country. Not sure where it is now or if there are multiple full-sized mockups, but I wouldn't be surprised if one ends up in the public collection at Udvar-Hazy Smithsonian Annex where many big NASA toys end up.
• amelius 5y ago
  Did you ever see images like these? https://www1.udel.edu/udaily/2009/may/cool051509.html https://www1.udel.edu/udaily/2009/may/cool051509.html Then it should not be surprising that a telescope is about that size.
• D_Guidi 5y ago
  just enjoy, if you have a disney+ account, the documentary "among the stars" where you can view the astronauts repairing the hubble telescope
• samstave 5y ago
  May I please subscribe to the raw images of ANY space telescope... I mean *WE* /paid/ for them... I would like to access the data provided in real-time. Where can one get the raw images?
  • tonmoy 5y ago
    These images would not be your typical jpg taken in the visible part of the spectrum. I’m not sure it is cost effective to host these image data for random people to download without any post processing. If you are dedicated enough to understand and post process the data yourself you can probably get access to the data for free
  • ceejayoz 5y ago
    Once they're taking images, you'll have access to them. Hubble's all went up (in raw as well as processed form) at https://hla.stsci.edu/ https://hla.stsci.edu/, http://hst.esac.esa.int/ehst/ http://hst.esac.esa.int/ehst/, and several other places. Expect the same for JWST. (Same for any other NASA mission. Here's the Curiosity rover: https://mars.nasa.gov/msl/multimedia/raw-images/ https://mars.nasa.gov/msl/multimedia/raw-images/)
    • spookthesunset 5y ago
      > Once they're taking images, you'll have access to them. What you say is true but with an asterisk. They grant time limited exclusive access to the data to whatever science team is using the telescope. It's basically an embargo agreement. That way the science team gets the first chance to do their research and publish it. Not all missions fall under this and in some cases you'll see what is going on right away. Eventually all data will become public. I'll just quote their policy[1]: Access to science data from most active missions is often limited to the Program Investigator Team during a period of exclusive access immediately following the observations. The duration of the exclusive access period ranges from a few months to as much as a year, depending upon the mission, the program category, and other factors. Some other data, such as those obtained during facility commissioning, or those that are found to duplicate concurrent observations by a Guaranteed Time Observer (GTO), may also be embargoed for a period of time. Data falling under exclusive access can be discovered via MAST public interfaces, but may not be retrieved except by authorized and authenticated persons. Following the expiration of the applicable exclusive access period, science data become available for public use without restriction. There is a ton more [2] about how to apply to get time on the telescope. Dudes even have a standalone desktop application to help put together the proposal. [1] https://archive.stsci.edu/publishing/data-use [2] https://jwst-docs.stsci.edu/jwst-opportunities-and-policies
• theandrewbailey 5y ago
  That animation seems right. Hubble space telescope is about the size and shape of a bus. https://www.nasa.gov/audience/forstudents/k-4/stories/nasa-knows/what-is-the-hubble-space-telecope-k4.html https://www.nasa.gov/audience/forstudents/k-4/stories/nasa-k... https://www.sciencefocus.com/space/hubble-space-telescope-how-far-can-see/ https://www.sciencefocus.com/space/hubble-space-telescope-ho...
• Sharlin 5y ago
  It’s really easy to get a wrong intuitive sense of the size of these things! I don’t understand why space agencies don’t always have human figures for reference in their visualizations. Or even a simple scale bar! We just get these silly “the size of a tennis court” type textual comparisons. Few people realize how big the Curiosity and Perseverance rovers are, as another example.
  • aksss 5y ago
    I believe the banana is the Internet standard for visual scale.
    • jl6 5y ago
      Also radioactivity, which also suits a Mars rover comparison.
  • deleted 5y ago
    [deleted]
  • egeozcan 5y ago
    > Few people realize how big the Curiosity and Perseverance rovers are To be fair, Perseverance looks as big as I imagined it would be, about the size of an SUV but wider (because even in 2020s, they still don't have streets in mars, what a bummer): https://www.nytimes.com/2020/03/05/science/mars-2020-rover-name.html https://www.nytimes.com/2020/03/05/science/mars-2020-rover-n... Or did my googling fail me? :) edit: direct image link around paywall: https://static01.nyt.com/images/2020/02/18/science/18mars2020rover03/18mars2020rover03-superJumbo.jpg?quality=75&auto=webp https://static01.nyt.com/images/2020/02/18/science/18mars202...
    • ravi-delia 5y ago
      My mental image until I looked it up was around the size of a dog. No, I don't know why
      • jpindar 5y ago
• lolive 5y ago
  Maybe that video can also help: https://svs.gsfc.nasa.gov/10776 https://svs.gsfc.nasa.gov/10776
• dr_orpheus 5y ago
  I'm trying to find an article with the exact story, but during the building of some of the early large satellites (something like the MilStar satellites [0][1]) they realized it would be really handy to be to rotate the satellite to work on it from different angles. So the satellite manufacturers repurposed rotary train car dumpers [2] in order to rotate the giant satellites. [0] https://external-content.duckduckgo.com/iu/?u=http%3A%2F%2Fclaudelafleur.qc.ca%2Fimages%2Fmilstar6.jpg&f=1&nofb=1 https://external-content.duckduckgo.com/iu/?u=http%3A%2F%2Fc... [1] https://en.wikipedia.org/wiki/Milstar https://en.wikipedia.org/wiki/Milstar [2] https://en.wikipedia.org/wiki/Rotary_car_dumper https://en.wikipedia.org/wiki/Rotary_car_dumper
• sp332 5y ago
  I think most satellites just unfurl solar panels. This one had to wrap up the big sun shield as well, and the lens pieces were kinda crammed together and then spaced out after deployment too. So the rocket couldn't fit something nearly as large as this as a payload going up.
• walrus01 5y ago
  The largest geostationary telecom satellites are also quite huge, if you were to stand next to one. In the range of 6500 kg weight and about the size of a school bus.
• ademup 5y ago
  I marvel at how small they are. Why not add 20, 100, or 1000 more mirrors to JWT? Or launch 10 more of these and go full interferometry? Maybe I've just been playing to much Dyson Sphere Program, but it feels to me that NASA et al are committing the cardinal sin of making the production loop too small.
  • gunsle 5y ago
    Probably because this project has been in development for decades and overran it’s timelines and budgets multiple times (to my knowledge). Congress already hates funding NASA, can’t imagine they were lining up to give them more money when I’m sure they had been asking when’s this thing even gonna come out? Also, FWIW, this thing has 100+ points of failure along its route to being fully deployed and getting to the L2 spot. A lot of people thought for sure at least one area would malfunction, would have easily doomed the whole launch. After this successful launch, it’s possible we’ll see discussion on building another in this design, but there is already a telescope in the planning stages for a 2027 launch, as well as four other concepts being developed for the future. https://en.m.wikipedia.org/wiki/Nancy_Grace_Roman_Space_Telescope https://en.m.wikipedia.org/wiki/Nancy_Grace_Roman_Space_Tele... https://space.stackexchange.com/questions/57407/are-they-already-planning-a-successor-to-the-jwst https://space.stackexchange.com/questions/57407/are-they-alr...
    • wolverine876 5y ago
      > Congress already hates funding NASA ? They seem to fund it quite a bit, for generations.
• 83 5y ago
  The nasa image[1] of employees with the scale model provides a better sense. [1] https://www.astronomie.nl/upload/750x498/images/Telescopen/JWST%20bij%20Goddard%20-%20credit%20NASA.jpg https://www.astronomie.nl/upload/750x498/images/Telescopen/J...
• elihu 5y ago
  I'm surprised that JWST isn't actually all that much bulkier than Hubble, despite the mirror(s) being so much larger. In retrospect I guess that makes sense, since much of Hubble's bulk is the long tube enclosing the mirror, which JWST lacks. Also, the size of things that can be reasonably launched into space is limited by the launch vehicles themselves. (Maybe NASA would have built it bigger if they knew exactly the launch vehicle specs that would be available at the end of 2021, or they might have waited for Starship, but obviously that couldn't have been predicted when work on JWST began.)
  • ehsankia 5y ago
    They're mostly limited by the size of the nose that goes on the rocket, which sadly hasn't advanced much in the past few decades. They were able to get a much larger mirror on there using a ton of clever engineering and folding, but the overall structure size is mostly limited by the payload size limit.
    • gpt5 5y ago
      Starship would supposedly fit the unfolded mirror as a single piece. There has been discussion in actually using starship itself as the structure for a future telescope.
• archibaldJ 5y ago
  basically spaceships to capture photons!