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Space Technology

Magellan II's Adaptive Optics Top Hubble's Resolution 136

Posted by timothy
from the no-longer-a-whole-lot-of-shakin'-goin'-on dept.
muon-catalyzed writes "The incredible 'first light' images captured by the new adaptive optics system called Magellan|AO for "Magellan Adaptive Optics" in the Magellan II 6.5-meter telescope are at least twice as sharp in the visible light spectrum as those from the NASA's Hubble Space Telescope. 'We can, for the first time, make long-exposure images that resolve objects just 0.02 arcseconds across — the equivalent of a dime viewed from more than a hundred miles away,' said Laird Close (University of Arizona), the project's principal scientist. The 6.5-meter Magellan telescopes in the high desert of Chile were widely considered to be the best natural imaging telescopes in the world and this new technology upgraded them to the whole new level. With its 21-foot diameter mirror, the Magellan telescope is much larger than Hubble with its 8-foot mirror. Until now, Hubble always produced the best visible light images, since even large ground-based telescope with complex adaptive optics imaging cameras could only make blurry images in visible light. The core of the new optics system, the so-called Adaptive Secondary Mirror (ASM) that can change its shape at 585 points on its surface 1,000 times each second, counteracts the blurring effects of the atmosphere."
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Magellan II's Adaptive Optics Top Hubble's Resolution

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  • by Russ1642 (1087959) on Thursday August 22, 2013 @09:40AM (#44641827)

    Right in the summary we have a comparison between the 6.5 m Magellan telescope and the 8 ft Hubble.

    • Re: (Score:2, Informative)

      by Anonymous Coward

      Well, the sentence where they compare the two is already converted to similar units, so it doesn't hurt my brain. YMMV

      • Re: (Score:2, Offtopic)

        by Russ1642 (1087959)

        My point is that they are mixing units together. Just pick one system, SI, and stick to it. If you can make it a whole paragraph without screwing that up then you get a gold star.

        • by krlynch (158571)

          Why? We switch units all the time, even when doing this "science" thing that so many seem to think only uses SI: eV, barn, torr, atm, etc. Suck it up, and learn to do conversions....

          • by ceoyoyo (59147)

            You don't use two different units for the same thing in science. Some of the units might not be technically SI, but there is almost always a specific unit that you're supposed to use for something. When there isn't, you certainly don't use two different ones.

        • by dywolf (2673597)

          I'd bet because the Magelen was specced in SI, and the Hubble wasn't. so the origianl source material that was snipped and molded into a submission has a conflict that the submitter deflated by adding the 21 to 8 comparison sentence.

    • Re: (Score:2, Funny)

      by Immerman (2627577)

      Hey, the whole point of using US customary units is to be kooky and incompatible right? Mixing units just makes it even better. Now if you'll excuse me I need to add a pint of lemon juice and a few liters of cream to this hogshead of soup I'm making.

      • Re: (Score:3, Interesting)

        by hedwards (940851)

        The whole point of using Imperial units is that we don't want to throw out trillions of dollars worth of infrastructure to make the Europeans happy. Seriously, spend a year in the US with our measures and spend a year somewhere that uses metric measures; metric isn't any easier for any thing you're likely to be doing on a day to day basis. Unless of course you're a scientist or engineer.

        • by hedwards (940851)

          I love how the pro-Metric people mod me down, rather than posing a substantive reason for doing it.

          I know the metric system, I've used the metric system and it contributes absolutely nothing in daily living. None of the conversions that it's optimized for occur in daily living with any regularity, whereas I regularly need half of something or 2x as much of it.

        • by jeremyp (130771)

          The whole point of using Imperial units is that we don't want to throw out trillions of dollars worth of infrastructure to make the Europeans happy. Seriously, spend a year in the US with our measures and spend a year somewhere that uses metric measures; metric isn't any easier for any thing you're likely to be doing on a day to day basis. Unless of course you're a scientist or engineer.

          (my bold)

          This is a story about science and engineering.

          • by hedwards (940851)

            Yes, but it's an article on an American site for a general audience. The mistake isn't that they used feet, the mistake is that they used metric for one and imperial for the other when they should have used feet in both instances.

            The people doing the engineering aren't doing it based upon an article written after the devices were engineered and built.

        • I find cooking slightly easier in metric. It still takes me a moment to remember how many teaspoons are in an eight of a cup, for instance.

        • by Immerman (2627577)

          Trillions of dollars worth of infrastructure? Really? Let's see - there's road signs... maybe plumbing... what other infrastructure is even affected by the units used? And generally speaking you don't have to throw out anything - infrastructure doesn't last forever, all you need is a policy that any significant repairs/refits use metric replacements, and a big box of adapters. Most manufactured goods have already made the switch - when's the last time you encountered an Imperial bolt when repairing somet

        • by ceoyoyo (59147)

          Yup, no difference at all. I mean, I'm just tightening this bolt and trying to grab the right wrench. So 7/16" is a little too small. Should I try 3/8" next? Or 1/2"? And did somebody just put this 15/32" in to screw with me?

        • by Nivag064 (904744)

          I was educated using Imperial units, but metric is so much easier to use.

          What is 1/2 of 1 5/8"?
          What is 1/2 of 35mm?
          The second question is far easier to answer!

          It is about time the USA adapted metric, and caught up with the rest of the World!

    • by dywolf (2673597)

      because taking the 0.09 seconds of mental math it takes to convert 6.5 into "~20ft" (or vice versa if so inclined) is too hard.

      • by dywolf (2673597)

        or even, hey, the summary also says the magellen is "21 feet" in direct comparison to the Hubble's 8. so the entire point of the thread is somewhat inflated to start with.

  • by philovivero (321158) on Thursday August 22, 2013 @10:17AM (#44642225) Homepage Journal

    As to the above drama about mixing measuring units, the article says:

    These images are also at least twice as sharp as what the Hubble Space Telescope (HST) can make because the 6.5m Magellan telescope is much larger than the 2.4m HST.

    So there you go. Both measurements in Imperial European Units.

    But then I read on, and was pretty stoked to see them discovering things like this.

    MagAO was then used to map out all the positions of the brightest nearby Orion Trapezium cluster stars and was able to detect very small motions compared to older LBT data, a result of the stars slowly revolving around each other. Indeed, a small group of stars called Theta 1 Ori B1-B4 was proved to be likely a bound “mini-cluster” of stars that will likely eject the lowest mass star in the near future (see figure 4). This result has just been published in the Astrophysical Journal.

    Nice! I'd love to see a time-lapse video over the course of the next million years watching this black sheep star get flung out of its little flock.

    • Nice! I'd love to see a time-lapse video over the course of the next million years watching this black sheep star get flung out of its little flock.

      You'll probably have to sign up for this service [slashdot.org] first.

    • by jlfose (1063282)
      It is truly amazing that this level of resolution is available to earth bound telescopes. Granted that the location of this telescope is in a very remote desert, but at least it is accessible without a rocket when something needs to be swapped out. What I would be interested in though is to see a comparison of the images that the upgraded scope can provide for exposures longer than 24hours. Perhaps Hubble still has an edge here due to the imperfections of being able to cancel out all atmospheric turbulen
    • by Solandri (704621)

      Nice! I'd love to see a time-lapse video over the course of the next million years watching this black sheep star get flung out of its little flock.

      Interesting bit of trivia - the first computational solution discovered for the 3-body problem [wikipedia.org] ended with one of the stars being flung out while the remaining two orbited each other as a binary system. It's since been found that most solutions end up this way [wolframscience.com]. Here's a video of one such system [youtube.com] ending with the middle-mass star being flung off.

  • by girlintraining (1395911) on Thursday August 22, 2013 @10:18AM (#44642247)

    Hubble was sent into space with a major glitch in its primary mirror. While yes, we were able to give it, achem, corrective lenses for its near-sightedness, it was never able to perform to original specifications. This project, by comparison... doesn't have a defect in one of its most important components. So I don't know if this is an entirely fair comparison to make...

    The fact is, they solve problems in two separate ways -- Hubble is a direct observation. There's no distortion, the light is the original and it's not smeared by atmospheric effect. Adaptive optics are amazing, but they're still additive in nature; You can photoshop, cut, and paste, but it'll never be quite as accurate as direct observation can be. That said, quite a lot can be done with it, and its a welcome addition especially in the age of limited scientific budgets for astronomy! I guess all I'm trying to say is... it's supplimentary, it is not a replacement for the kind of work Hubble did. We still need a replacement Hubble (obviously... with updated tech) for some observations.

    • by timeOday (582209) on Thursday August 22, 2013 @10:55AM (#44642801)

      it was never able to perform to original specifications.

      I thought the 2008 upgrade made it better than originally designed [newscientist.com]?

      With its new instruments, Hubble will be 90 times as powerful as it was supposed to be when first launched - it will be like having 90 of the original Hubble Space Telescopes, astronomers say. The improvement comes from a combination of increased sensitivity and wider fields of view, allowing Hubble to see 900 galaxies where its original instruments would have revealed only 10. HST will be about 60% more powerful than it was right after the third servicing mission, before ACS and STIS failed.

      • by hedwards (940851)

        From the looks of the article, it's 90x the repaired hubble's capabilities, which is probably 1/200th of what the Hubble would be able to do had it been launched with modern sensors today. The Hubble itself had 8 0.64MP CCDs to work with. Which at the time was quite good, but even if they used the CCD or CMOS from a low end dSLR, they could probably easily get 20x the pixels.

        • by Anonymous Coward

          the hubble telescope is diffraction limited to ~ 0.043 arcseconds (for optical wavelengths, 500 nm):
          http://www.spacetelescope.org/about/faq/
          this also states that it is slightly reduced by current camera resolution but post processing can pretty much remove that limit.

          the main article says that the ground based telescope can now achieve ~0.02 arcseconds

        • From the looks of the article, it's 90x the repaired hubble's capabilities, which is probably 1/200th of what the Hubble would be able to do had it been launched with modern sensors today. The Hubble itself had 8 0.64MP CCDs to work with. Which at the time was quite good, but even if they used the CCD or CMOS from a low end dSLR, they could probably easily get 20x the pixels.

          Correct. The original specifications of hubble, at the time it was put into orbit, would have achieved similar performance to what Magellan can do today. Considering the technological advances, Hubble could have kicked some serious ass. The fact is, no matter how good your technology, there is still some loss of quality from particulate matter in the atmosphere. Yeah, you can "content-aware fill" to remove the clouds... which is rather what Magellan does... but you can't get back the original pixels. You ca

          • by ceoyoyo (59147)

            You seem to make a lot of statements about things that you don't know very well.

            Hubble is diffraction limited by the size of it's mirror. It is not physically possible for it to resolve things smaller than that limit, which happens to be about twice that of Magellan II. The original spec for Hubble could not have exceeded that limit, unless it included a much bigger mirror (it didn't).

    • by Nemyst (1383049)
      A replacement Hubble would be really hard because it's not really about tech, it's about mirror size. Have fun designing a larger mirror which can still be launched by rockets into space without a ridiculously prohibitive price tag, all with NASA's funding being cut down dramatically.
      • by hedwards (940851)

        Sort of, the original sensors on the Hubble had very little resolution to them. With modern pixel density you could get much larger photos that could be enlarged to a greater extent. Mirror size does play a role, but when you're talking about replacing the 0.64MP sensors with 12MP sensors, you can pull in a lot more detail with any given size of mirror.

        • by ceoyoyo (59147)

          Hubble is currently very close to being diffraction limited - in other words, limited by the size of it's primary mirror. The original sensors were something like a factor of 2 away from that IIRC.

      • by azadrozny (576352)

        As I recall, the mirror size for Hubble was limited so that it could fit into the Space Shuttle payload bay. Since then, newer rockets have been developed that can lift heavier and bulkier objects into space.

      • by Russ1642 (1087959)

        I'll bet we could polish it to the right spec this time around.

    • by Dahlgil (631022)

      I don't consider adaptive optics "additive" or "artificial". Adaptive optics, as I understand them, do not add new light but correct existing light like a sophisticated focuser. To me, the non-corrected image distorted by the atmosphere is more artificial than the corrected image, in which the atmospheric distortion has been subtracted out . Just as the repair work on the Hubble (or the optics on your glasses) did not "create" new or artificial light, neither does adaptive optics. One of the ways this c

    • Keep in mind that Hubble's mission is far more than just pictures... (though they get all the attention). Hubble is also a spectrographic instrument - and it can "see" wavelengths that do not penetrate the atmosphere.

      There's more to astronomy than just who can create the sharpest and prettiest pictures.

  • by simonbp (412489) on Thursday August 22, 2013 @10:19AM (#44642267) Homepage

    What they rarely mention in these sorts of press releases (everyone with AO system has a "better than Hubble" press release) is that the cost of getting to that resolution is losing most of the light along the way. It's not hard to beat HST with perfect atmospheric correction, as Hubble is only a 2.4 m aperture, and nearly every AO system is on a larger telescope. It's just that the correction is achieved by sufficient optical contortions that only a small fraction of the original light actually makes it to the detector.

    My personal experience is that even the largest and most sensitive AO system in the world (NIRC II on Keck II with laser guide star) still really struggles make an observation in 20 minutes that Hubble can do in 5 minutes. If anyone were to launch a >3 m aperture visual-band space telescope (NOT JWST, that's IR), it would blow all these AO systems out of the water.

    • It's just that the correction is achieved by sufficient optical contortions that only a small fraction of the original light actually makes it to the detector.

      Got any numbers on that "small fraction"? Is most of it lost through the atmosphere, or inside the optics?

      • by Arkh89 (2870391)

        Surface times Integration time...
        Keck : 10m^2 and 30 minutes (yes, no need to count the pi/4 ratio as we will make a ratio out of it)
        Hubble : 2.4m^2 and 5 minutes.
        Ratio : approx. 1%

        What about the spectral range between the two?

        • I don't get it...

          Are you assuming Keck and Hubble both collected the same number of photons in that time? If so, why? And where did those numbers come from?

          • by Arkh89 (2870391)

            Yes, because photons are energy and all you care about is receiving most of it (actually transform it into a digital signal).
            The assumptions made are extremely light too (and it should be 20 minutes of integration time leading to a 1.44% ratio). I used the number of the original message.
            - Same absorption from entrance aperture to the sensor.
            - Same sensor sensitivity (photon efficiency).
            - Same sensor Signal To Noise Ratio (SNR).
            - Same spectral bandwidth.
            - Same spectral response of the global instrument in th

            • OP's statement from personal experience that

              [Keck] still really struggles make an observation in 20 minutes that Hubble can do in 5 minutes

              doesn't really sound like a scientifically solid statement from which to be doing calculations. That you might lose 99% of the signal from atmospheric effects and the like (despite AO) doesn't sound too unreasonable, but losing a large percentage of the light was what I was really questioning.

              Are you assuming Keck and Hubble both collected the same number of photons in that time?

              Yes, because photons are energy and all you care about is receiving most of it (actually transform it into a digital signal).

              I still don't get why you'd assume Keck is only detecting the same number of photons in 30 (or 20) minutes as Hubble does in 5.

      • by simonbp (412489) on Thursday August 22, 2013 @11:39AM (#44643435) Homepage

        Inside the optics. For optical/near-IR astronomy (i.e. roughly in the wavelengths that your eyes can see), atmospheric opacity only comes into play if there are clouds. You always want to look at objects higher in the sky (meaning through less atmosphere), but that's more because they have less distortion.

        Inside the telescope, you lose some light every time you have a reflective surface. A simple telescope might have three reflective surfaces at 0.9 reflectivity, and so no more 3/4 of the original light reaches the detector. A complex AO system typically has closer to ten mirrors, so no more than a third of the original light will reach the detector. And that's before you account for all the other losses, like scattered light and the parts of the distortion that deformable mirror in the AO system can't correct for. So at worst case, it might be only 10% of the original light making it to the detector.

        AO systems are great, especially for bright targets, but it always makes me cringe when people claim they are "better than Hubble". Space telescopes exist for reason...

        • by Arkh89 (2870391)

          I doubt that they use mirrors with a reflectivity of only 90%. This might be true on large surfaces (meters+), with dust on it, but on smaller surfaces it gets more toward 99%.
          For instance, simple Al2O3 coating has a reflectivity over 95%. And this is a basic coating, TiO2 can achieve 99%+.

          • by Shag (3737)

            Reflectivity is also going to be affected by what wavelength they're observing at. Typically, AO is used for near-IR observations. Although I forget the exact figures, I know Gemini North uses silver to coat its primary now because it only absorbs something like 1/4 as much NIR as aluminum did. /Former aircraft spotter for the AO lasers at GN and Keck

        • by tyrione (134248)
          One would expect the denser the atmospheric composition of gases and thus the stronger the electromagnetic field the greater the distortion, cloud cumulation aside.
    • still really struggles make an observation in 20 minutes that Hubble can do in 5 minutes.

      Presumably this is a function of area? Does that mean double-diameter ground-based AO telescope will be as good as Hubble? How do the costs compare? (I realize doubling the area isn't a trivial undertaking).

      As I understood it, the next 'frontier' in space telescopes was going to be a constellation parked out at a LaGrange point, not just a bigger Hubble since AO has made that type of telescope not worth doing. Somebo

    • by Kjella (173770)

      My personal experience is that even the largest and most sensitive AO system in the world (NIRC II on Keck II with laser guide star) still really struggles make an observation in 20 minutes that Hubble can do in 5 minutes. If anyone were to launch a >3 m aperture visual-band space telescope (NOT JWST, that's IR), it would blow all these AO systems out of the water.

      Yes, but "Hubble resolution, at a price" makes it sound like Hubble was the expensive one.

      From its original total cost estimate of about US$400 million, the telescope had by now cost over $2.5 billion to construct. Hubble's cumulative costs up to this day are estimated to be several times higher still, roughly US$10 billion as of 2010.

      Compared to that, the Magellan telescopes [noao.edu]

      Total annual costs $10,437,639

      That figure is including amortization of the $73 million dollar ($3,665,250*20) investment so $200 million total over 20 years. This means you can get 50 AOs for the cost of one Hubble, now which one comes "at a price" again?

    • by hedwards (940851)

      Not really, you're ignoring changes in technology. These days it's relatively easy to create a sensor where nearly 100% of the light falling on the chip will hit one of your photosites. A typical dSLR sensor will have magnifiers that cover effectively 100% of the area.

      I doubt that the original Hubble was as efficient with the light hitting the sensor as a modern dSLR sensor is. Sure, you do lose some photons in the process, but damn near all of them will hit one of the focusing lenses and be directed into a

  • the Magellan II 6.5-meter telescope... [w]ith its 21-foot diameter mirror

    Oh, for... one or the other, c'mon.

  • You do realize there's just a bit of time lag here?

    The Hubble was supposed to launch in 1983 (delays in building and the Challenger disaster held it up till 1990). So, it's at best 30 year old tech (and actually since it was space rated, a good bit older than that).

    The Magellan II is brand spiffy new and can take advantage of many things that Hubble can't since it needs to be at least somewhat rad hard.

    Granted that Hubble has been upgraded, but I don't think it's a fair comparison.

    If we ever get the James W

    • by ceoyoyo (59147)

      It is a fair comparison, because one of the drawbacks of space telescopes is that they cost a godawful amount to upgrade. Magellan II is new, but the AO tech it uses may well be installed on older telescopes. Most of the big ground telescopes have been upgraded many times, including with AO. Hubble got upgraded a couple of times, each at a cost that would have built many big ground telescopes.

  • I don't know what the current state of the art is, but once upon a time it was only possible to correct a for atmospheric variations over a very narrow field of view. You will notice that the first light images are of binary stars and not of whole nebulae or galaxies. I don't think this is an accident.
    • by Shag (3737)

      I don't know what the current state of the art is, but once upon a time it was only possible to correct a for atmospheric variations over a very narrow field of view.

      There are different goals at play. A lot of astronomical research - usually the kind of thing you'd be using adaptive optics for - can be done with a very narrow field of view - for example, studying specific distant galaxies, pulsars, quasars, transiting exoplanets, etc. Even the field of view required to image other planets in our own solar system [hawaii.edu] is fairly small. So it's not at all uncommon to have instruments with fields of view less than one arcminute for observing single objects.

      On the flip side, i

  • by GeekZilla (398185) on Thursday August 22, 2013 @02:32PM (#44645745)
    We can finally quiet the "moon landing was a hoax" nutjobs. With the ability to make long-exposure images that resolve objects just 0.02 arcseconds across — the equivalent of a dime viewed from more than a hundred miles away", we can actually take pictures of all the junk we left behind as proof that we were actually there.
  • So when do we get the really cool pictures from Magelan II, in higher resolution than we got from Hubble?

    Iconic photos like Mars:

    http://commons.wikimedia.org/wiki/File:Mars_Hubble.jpg [wikimedia.org]

    Jupiter:

    http://commons.wikimedia.org/wiki/File:An_Ancient_Storm_in_the_Jovian_Atmosphere_-_GPN-2000-000910.jpg [wikimedia.org]

    Saturn:

    http://commons.wikimedia.org/wiki/File:Saturn_with_auroras.jpg [wikimedia.org]

    And the Hubble Deep Field:

    http://commons.wikimedia.org/wiki/File:Hubble_ultra_deep_field.jpg [wikimedia.org]

    And completely off-topic, how often do you see a color pho

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