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Ask Chris McKinstry About Giant Telescopes, Etc.

Have you ever heard of Chris McKinstry? If not (I hadn't until a few weeks ago), it's probably because he's been moving too quickly in the background for you to apprehend with human vision. In addition to operating the world's largest optical telescope -- the ESO Very Large Telescope (VLT) at Paramal Observatory (Atacama, Chile) -- he writes and reviews books, hacks consciousness, creates art, and enjoys his family. Chris has agreed to field questions about the VLT, as well as about the upcoming OWL (OverWhelmingly Large) telescope project -- a 100-meter filled-aperture device which would put all current terrestrial telescopes to shame. Please read through the linked sites, then post your questions (one per comment, please) for Chris below; we'll pass along the best ones for his reply.

138 comments

  1. Hey... by AntiPasto · · Score: 2
    you know what they say about the size of a man's telescope... nudge-nudge, wink-wink...

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  2. might as well ask it now.. by Blue+Lang · · Score: 5

    i noticed in your 'fave books' section that you have the blind watchmaker, et al.

    so, with an eye towards dawkins' views on evolution, what's your personal take on the probability (not the possibility) of humans locating extraterrestrial life without going outside the solar system?

    --
    i browse at -1 because they're funnier than you are.
  3. Terrestrial Optical Telescopes by pb · · Score: 5

    What are the benefits of having an Earth-bound, optical telescope?

    Or rather, what can a larger optical telescope find better from Earth that we can't already find on other wavelengths and from other venues (i.e. The Hubble)?

    If there are no advantages here, is it more cost-effective, or what?
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    pb Reply or e-mail; don't vaguely moderate.

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    1. Re:Terrestrial Optical Telescopes by chgreer · · Score: 3

      Or rather, what can a larger optical telescope find better from Earth that we can't already find on other wavelengths and from other venues (i.e. The Hubble)?

      Think about trying to blast an 8.4m mirror into space -- imagine how much fuel you'd have to expend and how much it would cost. I once read that one space shuttle mission costs up around a billion dollars per launch, the cost of the payload not withstanding.

      The dual Gemini telescopes that NOAO and a group of others are putting together are nearly 4 times the size of HST. NGST, or the next generation space telescope is years away from being launched (2010, maybe?) and will only be 6.4m.

      (For those who don't know, a bigger mirror means more light gathering power (ie, fainter objects.) and higher spatial resolution (things are less fuzzy), so it is in effect, possible to build ground telescopes that are big enough to out resolve HST, even after dealing with atmosphereic corrections.

      (Also, fwiw, spain will be building a 15m on the canary isles soon.) There is also the Large Binocular Telescope in AZ that will be going on line in 5 years or so that will have 2 8m mirrors that have the resolution of 1 18m mirror, and will allow astronomers even higher resolution.

      So, the say it in a line: space is not the end all and be all of optical astronomy, no matter what STScI wants you to believe.

    2. Re:Terrestrial Optical Telescopes by Uncertain+Bohr · · Score: 1

      An 8m telescope provides a much larger light collection area than a 2.4m telescope such as HST. This make the VLT (and Keck) a very good place to look for veru faint objects which would be very hard to image with HST (i.e. a prohibitively high number of orbits would be necessary). There is also the fact that VLT is not one but four telescope (i.e. 4x8m class) and that there is a vcery broad range of instruments available (high resolution spectrograph, very sensitive IR camera etc..)

    3. Re:Terrestrial Optical Telescopes by eVarmint · · Score: 2
      Or rather, what can a larger optical telescope find better from Earth that we can't already find on other wavelengths and from other venues (i.e. The Hubble)?


      The OWL article answers this question nicely. The short of it is this:

      1) Ground is way cheaper. At $1 Billion, the OWL will still be much cheaper than Hubble.

      2) Adaptive optics can get you close to diffraction-limited resolution, which makes putting a telescope in space less compelling.

      3) Bigger telescopes mean you can see much fainter objects and do lots more science in the same amount of time, saving even more money.


      So basically, for the same amount of money as a space telescope you can get a telescope on the ground that sees farther and more clearly.


      The real advantage of space telescopes is being able to see light that is absorbed by the atmosphere, and the ability to have huge baselines for interferometers. Both of these advantages should be considered complimentary to ground based telescopes, and not competative.

  4. Christie Brinkley?? by grammar+nazi · · Score: 1

    Why would we interview Christie Brinkley about telescopes???!!?!

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    Keeping /. free of grammatical errors for ~5 years.
  5. BHT (Big Honkin' Telescopes) by Golias · · Score: 3
    With so many "purdy pictures" coming in from the Hubble, and more orbital telescopes planned, it seems that we might approaching the point of diminishing returns for bigger ground-based telescopes.

    Other than cost savings and easy access for changes, are there many advantages to staying on the ground?

    --

    Information wants to be anthropomorphized.

  6. funding by jmayes · · Score: 5

    What's the biggest hurdle to hop over in getting funding for projects like OWL?
    And how did you pull it off?

  7. Telescope naming conventions by komet · · Score: 2

    How do telescope designers come up with all those names? "Very Large Telescope", "OverWhelmingly Large ..", .. when will it all end? Will the 1000th telescope system be called "Obscenly Fucking Gigantic Big-Mama Mega Telescope"? It's not like Intel calls its latest processor "Very Very Very Fast 86". The only other group I know with such silly names are particle collider folks..

    So, when will a new naming scheme come up?

    :)

    --
    Any technology which is distinguishable from magic is not sufficiently advanced.
    1. Re:Telescope naming conventions by Mignon · · Score: 2

      I think the BFT-9000 is next...

    2. Re:Telescope naming conventions by Keeper · · Score: 1

      I guess you never really played streetfighter...

      Streetfighter II
      Super Streetfighter II
      Turbo Streetfighter II
      Alpha Streetfighter II
      Turbo Alpha....

    3. Re:Telescope naming conventions by proj_2501 · · Score: 1

      We just need to translate Japanese telescope names. I can see it now:

      Super Skill Wild Dance Telescope
      Ultra Best Light Telescope
      Hyper Enormous Telescope Mega
      Maximum Size Sight Telescope
      --

    4. Re:Telescope naming conventions by TheFallenWeeble · · Score: 1

      Agreed, the names are kinda silly, but to the contrary, there are other weird-ass names like this. Some good examples (probably seen even in Intel at least occasionally):

      LSI Circuit - Large Scale Integraged Circuit

      VLSI Circuit - Very Large Scale Integrated Circuit

      VHF - Very High Frequency

      UHF - Ultra High Frequency

      You see stuff like this a lot in scientific research. Apparently, terms like "very" and "ultra", and now "overwelming" (new to me) have specific value ranges associated with them.

      Of course, there is the chance that I don't know what I'm talking about...

    5. Re:Telescope naming conventions by homebru · · Score: 1

      Japanese - English names would probably be more like:

      Violent Squirrel Superscope
      Lucky Bubblegum Nova Catcher
      Purple Mountain Medusa MegaScope
      Atomic Aubergine Stellar Discoverer

      Or, to try to bring more fems into science:

      Lunar Twilight Kiss Telescope
      Dancing Starbeams Telescope

  8. Why single-mirror? by jd · · Score: 5
    I could have been mis-reading the article, but it seemed to me as though the idea was to build a single-mirror system. On the other hand, in radio astronomy, and in the insect world, arrays are considered the norm.

    Is there some advantage that a single mirror gives that cannot be duplicated using multiple smaller mirrors? (Simpler optics is an obvious one, paradoxically. :) Or is this (at least in part) NerdTrek III: The Search for Sponsors, where a record-setting single telescope is going to get more interest than a comparable array?

    (A supplementary question, to go along with this. Let's say, for the sake of argument, that optical arrays are practical. Do you see any possibility of optical astronomers adopting the same line as radio astronomers, in trying to build an effective 1Km+ optical telescope, using an array?)

    --
    It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
    1. Re:Why single-mirror? by phil+reed · · Score: 2

      Just for the record, when the Paramal Observatory is finished as planned, it will have 4 large telescopes running in an optical array.


      ...phil

      --

      ...phil
      "For a list of the ways which technology has failed to improve our quality of life, press 3."
    2. Re:Why single-mirror? by pq · · Score: 5

      This is deep, so I won't do a good job of explaining this, but let me take a stab at it anyways... The fundamental difference is that quanta of light (photons) have more energy than quanta of radio waves (also photons, but ever hear them called that?): E = hf, as Planck tells us. So for a given signal strength, there are far more radio photons than there are optical photons - this implies that optical telescopes are in a quantum regime (shot noise limited), while radio telescopes work in a classical regime (thermal noise limited). So what? So: radio signals can be received and amplified and replicated "perfectly" - each telescope output can be split into N identical copies to be correlated against the other N telescopes in the array. But optical photons cannot be received and amplified without destroying coherence - so the light form one mirror has to be split N ways to be combind with the other N telescopes. That's why optical interferometry is only possible with huge mirrors like the VLT, where for 4 mirrors, 1/3 the light from each telescope is still enough photons to work with. For radio telescopes: add more scopes? Sure, just boost the amplifier some more. Optically, to add another scope, you need to increase collecting area by (N+1)/N. This is a fundamental limit, sadly - so it keeps us radio astronomers in business and makes optical interferometry very very hard... - pq: I can't login today, for some reason.

      --
      "I will take the Ring," he said, "though I do not know the way."
    3. Re:Why single-mirror? by pq · · Score: 1
      F***! It posted under my name, but stripped the HTML formatting. I don't get it - what's up with /. today?
      Anyone?
      Anyone?
      Ferris?

      --
      "I will take the Ring," he said, "though I do not know the way."
    4. Re:Why single-mirror? by gotan · · Score: 2

      I think that is addressed under the keyword scalability: "Perhaps the most far-reaching innovations have been brought by the Keck, with virtually unlimited scalability of the telescope primary optics". The Keck telescope consists of 36 smaller mirrors (supplied by Kodak). Since for such big telescopes active optical control (meaning that the mirror(s) can be deformed slightly by special elements under them) is necessary anyway to counteract athmospheric effects and structural relaxation in different positions the problem of microadjusting all those smaller mirrors could be addressed by the active optics (though this is apparently still an issue).

      This might also mean that the OWL could already start working before the main mirror is completely assembled, probably starting with the outer ring to make most of the diameter.

      --
      "By the way if anyone here is in advertising or marketing... kill yourself." -- Bill Hicks
    5. Re:Why single-mirror? by F0rlorn · · Score: 1
      A big problem with one large mirror is the heat they retain. Just as heat waves distort light during busy traffic, it can mess up the images taken in by a telescope.

      Small mirror arrays stay away from this problem. If they are, in fact, making one big mirror, how did they dodge this problem?

      --
      - Justin
    6. Re:Why single-mirror? by Jeremy+Erwin · · Score: 1

      The pages on the 100m telescope cover this. Basically, interferometry isn't as effective as a filled aperture telescope in terms of field of view and magnitude limits. However, the authors of that study do speculate, briefly, on the possibility of 1km-100km interferometers.

    7. Re:Why single-mirror? by jd · · Score: 2
      The slashdot db seems to be manglified. Slashdot's been reporting all sorts of strange errors, from syntax errors to invalid form ids, this afternoon.

      I think it's the Greys from Redmond, Alpha Centauri, upset at the telescope plans, which'll show their top-secret random number generator - oops, software design centre.

      --
      It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
    8. Re:Why single-mirror? by mperrin · · Score: 1
      Is there some advantage that a single mirror gives that cannot be duplicated using multiple smaller mirrors?

      No, not if given a sufficiently large number of smaller mirrors, but that number may be very large. But multiple mirror systems (which are called interferometers) are much, much harder to build than single mirror systems. Before getting into the real details, here's a quick crash course in telescope design:

      The two most important properties of any telescope are its light-gathering power and its resolution. The first is how many photons per second it can catch. This is directly related to the area of the scope: a 8m scope has 16x the area of a 2m scope, so it needs 1/16 the exposure time to get a comparable image. In other words, a single VLT dish can capture as many photons from a given source in an hour and a half as the Hubble would get in a full day. So obviously bigger scopes are better. In the case of OWL, a 100m telescope has the same area as 100 10m telescopes. So you'd need a pretty hefty array to get the same light gathering power.

      The second property we care about is the resolution, which is the size of the details which can be seen in images from the telescope. This is where interferometer arrays really shine. A telescope with finer resolution can see smaller details, obviously a good thing. Now without going into the details, the resolution is limited by quantum mechanics to be proportional to Wavelength/Diameter, where Wavelength is the wavelength of light you are using and Diameter is the side-to-side diameter of the telescope. So to see fine details, you want W/D to be as small as possible. There are two ways to do this.

      Way one: Use as small a wavelength as possible. If you use a bigger wavelength, you need a larger diameter to compensate and still get decent images- which is why radio scopes (large wavelength) are all humongous.

      Way two: Use as large a diameter as possible. Here's the kicker, which is why arrays are so desirable: In a properly built interferometer, the "Diameter" is NOT the diameter of a single dish, but rather the total side-to-side distance of the entire array! So if you've got two 1m telescopes 100m apart from each other, you have the resolution of a 100m telescope! (but only the light-gathering power of a 1.4m telescope, because that's all the area you have.)

      Now, the thing is, hooking together the elements of an interferometer to get this good a resolution is highly nontrivial. You don't just take a different picture with each scope and superimpose them in photoshop. Rather, you have to mix together the full raw signals from each telescope in a very precise way so that the phases of the different signals interfere with each other, canceling out in some parts, adding up in others, and giving you the super-detailed final product you desire.

      In the case of radio, the frequencies dealt with are on the order of a couple hundred megahertz. (Higher frequencies in the GHz can be mixed down to MHz via heterodyne receivers.) We have electronic components that can work at MHz speeds - amplifiers and high-speed tapes and relays and all that. Thus it's possible to do all the mixing in electronics, which is how the VLA in New Mexico works, and how the world-wide VLBA works, too. Take a dozen scopes around the world, have them all observe things simultaneously, recording onto high-speed mag tapes, then Fedex all the tapes to a computer center and run them all through a correlator, and out pop your images.

      In contrast, at visible light, we're dealing with frequencies many orders of magnitude above what our fastest electronics can handle. There's no way in hell we can handle petahertz signals in electronics right now. Which means the only way to do the mixing is optically: stick a mirror at the focus of all the telescopes, and physically direct all the light from all of them to the same focal plane, via light paths of -exactly- the same distance (and we're talking "nanometers" when we use the word "exact" here.) Right now the limit for this sort of thing is a hundred meters or so, barely. It will be many, many years before we can pull off a 1 km optical interferomter on the ground, but there are certainly people working on it.

      This is, unsurprisingly, really damn hard. Only in recent years have we started having any success with optical interferometry at all. It's very new technology. It's extremely promising, in that you can use it to get vastly higher resolution than you can with a single dish scope, but it's very difficult and extremely costly. Couple that with the fact that you still need large telescopes to have enough collecting area to see faint objects, and it becomes clear that there will still be a place for large single scopes for a long time to come.

    9. Re:Why single-mirror? by pq · · Score: 1
      how the world-wide VLBA works, too. Take a dozen scopes around theworld, have them all observe things simultaneously, recording onto high-speed mag tapes, then Fedex all the tapes to a computer center and run them all through a correlator, and out pop your images.

      Heh, I work on the VLBA, and I wish my images popped out that easily... :)

      You'll notice my other comment in this thread for some other good reasons why optical interferometry is harder than radio...

      --
      "I will take the Ring," he said, "though I do not know the way."
  9. Why can't you guys think of some decent names? by Psiren · · Score: 2

    VLT = Very Large Telescope.
    OLT = Overwhelmingley Large Telescope.

    Kinda boring no? Haven't you astronomers got *any* imagination? ;-)

    Now weary traveller, rest your head. For just like me, you're utterly dead.

    1. Re:Why can't you guys think of some decent names? by TheTomcat · · Score: 1

      SXLHBMFT.

      Super X-Large Huge Bigass Mo Fo of a Telescope?

      (I'm not an astronomer.)

    2. Re:Why can't you guys think of some decent names? by Mononoke · · Score: 1
      Will the next project after OWL be named BFT?

      (That's Big F***ing Telescope to us mortals.)


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      NetInfo connection failed for server 127.0.0.1/local
    3. Re:Why can't you guys think of some decent names? by cowscows · · Score: 1

      My Vote is for BFT 9000.

      --

      One time I threw a brick at a duck.

    4. Re:Why can't you guys think of some decent names? by pb · · Score: 1

      Oh yeah right, like we're any better.

      (or don't you know what VLSI stands for? :)

      I'm pushing for RDBICASWTMT, myself, but IANAEE.

      (For the acronym and humor-impaired, that's "Really Damn Big Integrated Circuits And Stuff, With Too Many Transistors"; but "I Am Not An Electrical Engineer")
      ---
      pb Reply or e-mail; don't vaguely moderate.

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      pb Reply or e-mail; don't vaguely moderate.
    5. Re:Why can't you guys think of some decent names? by Psiren · · Score: 1

      People like you make me sick.

      That's wierd, cos humour impaired people like yourself make me laugh. Lighten up, life's too short.

      Now weary traveller, rest your head. For just like me, you're utterly dead.

    6. Re:Why can't you guys think of some decent names? by cburley · · Score: 1
      How about "YAAAEWITTYTH!", which stands for:

      You Are As An Electron Wandering Inside This Telescope, You Tiny Human!
      --
      Practice random senselessness and act kind of beautiful.
    7. Re:Why can't you guys think of some decent names? by tcomeau · · Score: 1
      Even when they try to get good names, the names get mangled. The huge radio telescope at Green Bank, WV is officially named The Green Bank Telescope but everyone I know who has seen it calls it The Great Big Telescope.

      tc>

      --

      tc>
      Most Americans don't understand science, and they wouldn't like it if they did.

  10. vs HST by Anonymous Coward · · Score: 1

    At what point does a ground-based telescope approach the resolution of the HST? Will the new telescope approach this?

    1. Re:vs HST by Uncertain+Bohr · · Score: 1

      With interferometry, using the four VLT plus the upcmoing sideostats telescope, astronomers will be able to reach a much much higher resolution than HST. HST's resolution is about 75mas (i.e. 0.075" which is much smaller than the atmospherically imposed limit of 0.3"(for a VERY good site like VLT's or Kecks') to 1.0". However, resolution of 0.075" HAVE been obtained from the ground using what is called Adaptive Optics: there are ways to compensate for the blurring effect of the atmosphere using deformable mirror which undo the effect of the atmosphere moving on top of the telescope (This is where laser are sometimes used).

  11. A little prediction... by Explo · · Score: 2

    I'm sure that sooner or later in this post the usual argument raises its head: "What real use this has? Astronomy is not an useful science, and the funds should be instead transferred to something sensible and useful!"

    I've usually just defended astronomy, but for once I want to be faster than the bashers ;)

    --
    Everyone who makes generalizations should be shot.
  12. How parellelizable? by Omnifarious · · Score: 5

    How parallelizable is the problem of micro-adjusting small portions of a large deformable mirror to correct for atmospheric distortion?

    I remember a Scientific American article stating that you'd have to devote a top-of-the-line Cray to continuously recalculate the deformations needed given data from the guide star, or laser simulated guide star. If this problem is highly parallelizable, you may be able to get away with _much_ cheaper hardware.

    I'm sure the idea has occured to you, but I want to know what your thoughts are on it.

    1. Re:How parellelizable? by scotch · · Score: 1
      What scientific american issues/article was that? Much of the calculation can be done with specialized hardware, which has been used in at least one system since the 1980's. It all depends on how big your aperature is, how fast the atmosphere changes (bandwidth of compensation calculations), how many deformation elements are in your array (designed to match seeing quality at telescope site), etc.

      What's even more interesting, IMO, is atmospheric blur compensation can be done without adaptive optics using high speed imaging and some heavy duty post processing. Results aren't quite as good as AO, but the cost is far less. Hybrid systems (AO plus post-processing image reconstruction techniques) give you the best bang for the buck.

      --
      XML causes global warming.
    2. Re:How parellelizable? by mcgyver · · Score: 1

      There are new multigrid reconstruction algorithms that are considerably faster than the standard huge matrix mulitiplication that is most often used. DSP boards can do the job no problem.

    3. Re:How parellelizable? by Uncertain+Bohr · · Score: 1

      This is indeed a problem for telescope such as OWL which would require many nodes to be adjusted in real time. The hope is that Intel et co. continue down the path of Moore's law. Another problem which LARGE telescope is that they are usually designed to provide a large field of view which are meant to be observed with very large format arrays of detectors. There are some 16k x 8k, or even larger arrays observing around the world, and the data they generate is actually large enough to be difficuly to store AND to analyse since each image is several hundreds of megabytes and that hundreds of these can be acquired on any given night...

    4. Re:How parellelizable? by TPx · · Score: 1

      On a 4mt-class telescope, it takes 1024 small transputers and one PC running Windows and IDL. It's more than enough, all the work is done by the transputers (FFT , etc...) and the PC has just to coordinate the workload.

  13. Why on the ground by ocelotbob · · Score: 2

    With all of the problems our ground-based telescopes being blinded by lights of urban sprawl, why are you continuing to build terrestrial-based telescopes? It seems more and more obvious, at least to me, that we should be working towards putting the next generation of megatelescopes in space, so that we could use them basically 24 hours per day, and not have to worry about that metropolis growing every day.

    --

    Marxism is the opiate of dumbasses

    1. Re:Why on the ground by lennon · · Score: 3

      It is cheaper to control light pollution than build something in space. http://www.darksky.org is just one of the places where a little money go a long way to fight light pollution.

    2. Re:Why on the ground by Omnifarious · · Score: 2

      I can tell you the answer to this one.

      The bigger your telescope, the more light you can gather and the finer the detail you can resolve. The problem that caused space spaced telescopes to be planned is atmospheric distortion. The density of the atmosphere, and hence its refractive index, changes in a complicated, almost random pattern. It's why stars twinkle.

      OWL will be a deformable mirror telescope. It will technically not be a single mirror telescope, but a whole gigantic array of hexegontal deformable mirrors all abutting eachother. The fact that the mirrors are deformable means that you can use light from a bright object or laser beam to on-the-fly recalibrate the mirror for atmospheric distortion effects, resulting in a clear picture.

      Building a large mirror like this in space would be very costly. Much more costly than building it on the ground. And previous problems that have made large mirrors not very useful on the ground now have solutions.

    3. Re:Why on the ground by drudd · · Score: 2

      Actually the Hubble cannot be used anywhere near 24 hours a day. You have the problem of avoiding the very bright sun and moon, both which would easily damage the sensitive instruments.

      You also have the problem that at any given time half of the sky is blocked by the earth.

      Doug

      --
      Venn ist das nurnstuck git und Slotermeyer? Ya! Beigerhund das oder die Flipperwaldt gersput!
  14. Can you track something fast? by lennon · · Score: 2

    Could this scope be trained on the moon, or even on something even closer by, like a spacecraft in orbit? Would the slewing system be nimble enough to track something moving very fast (like the spacecraft or the moon), or to get to a place where gamma ray burst was detected fast enough?

    1. Re:Can you track something fast? by Uncertain+Bohr · · Score: 1

      The VLT can track pretty fast but not quite fast enough, AFAIK, to track a low Earth orbit satelite. The Moon was observed with it, I hear, but the problem here is that the Moon is really really bright for such a large telescope and that there are some heating considerations to keep in mind when trying to look at objects like the Moon with very large telescope. There are some 3m class telescope in Hawaii which can track fast enough to look at satelites. I believe that these are used to look for Earth-orbit crossing asteroids.

  15. Atmospheric Turbulence Correction? by exploder · · Score: 3

    I've read a little bit about mechanisms to correct for atmospheric distortion using adaptive optics. To what degree can these systems reduce the distortion that an earth-based telescope suffers? Will advances in this area make it less attractive to put an optical telescope in space, given that the cost of lifting it into orbit can instead be used for corrective systems, and to build a larger instrument?

    --
    Yo dawg, I heard you like the Ackermann function, so OH GOD OH GOD OH GOD
  16. Sky & Telescope Magazine - Off Topic by hughesma · · Score: 1

    This isn't related to the interview but might help others here. This month's issue of Sky & Telescope Magazine has a large article dedicated to this very subject. Radio and Optical I believe (I just recieved it yesterday so I haven't had the chance to read it yet). Might help those people who want a bit more information or just wanna look at the purty artist renderings.

    http://www.skypub.com/skytel/skytel.shtml

    --
    ----------------------------------------- Well damn...so that's what that does...
  17. Focal-Length and/or Range of View by dloolb · · Score: 1

    With all these monster telescopes just over the horizon (Good article in Sky & Telescope this month) aimed at discovering further into the deepest pockets of the universe. My question is what kind of detail can be seen to nearby cellestial objects, ie.. the moon, the ISS passing overhead. Or are these objects too close to see in detail. I thought it would be great to zoom in on the moon where we landed and see the footprints, or landing cradle, or watch the astronauts assemble the ISS. Just a few thoughts.

    --
    The electric yellow has got me by the brain banana
  18. Yeah, they're big... by viper21 · · Score: 5

    But what do you do with them?

    What kind of work do the telescopes at your facility generally do? Do local astronomers get to come in and do research or are the scopes reserved for some large project?

    Thanks,

    -S

    Scott Ruttencutter

    1. Re:Yeah, they're big... by mperrin · · Score: 1
      The VLT is what is called a "facility telescope", meaning that the facility is open to researchers from around the world to apply for time there to do research. Basically a PI comes up with a proposal for what he wants to do with the scope and how much time he needs at what part of the year, and submits that proposal to a TAC (Time Allocation Committee). The TAC decides which proposals make the grade, and at the appropriate time of year the PI (or more likely their grad students. ;-) catch a plane to Chile and do their observations.

      So yes, in answer to your question, all sorts of different projects and observations are going on at the VLT, just as at Keck or any of the other major scope facilities.

      One caveat to this is that the details of who gets how much time are very much wrapped up in the funding of the telescope. The organizations which fund the telescope understandably get the bulk of the time, even if they do offer some of the time out to observers at large. The VLT was funded by the ESA, so most likely the time is allocated out primarily to European observers, although I haven't checked the specifics of the TAC policies myself.

  19. a good telescope question by gtx · · Score: 2

    what is your take on having telescopes with mirrors and lenses polished by nanomachines? it sounds like a good idea. just think about it... molecular sized defects taken out by little machines! it may be a bit far off, but i wanted to know if you thought it sounded like it was at all possible, or if it's even a good idea.

    --


    "I hope I don't make a mistake and manage to remain a virgin." - Britney Spears
  20. CCD or what? by paRcat · · Score: 4

    What kind of imaging does a telescope of this scale use? Is it an OWLCCD or something else? What kind of resolution? And how far away would an object need to be before the resolution becomes a shortcoming?

    1. Re:CCD or what? by Uncertain+Bohr · · Score: 1

      You can find all this information at http://www.eso.org/observing/instrumentation.html

  21. Moon closeup by russiste · · Score: 3

    I've always wondered: "now" that we have incredibly powerful telescopes, wouldn't be possible to take closeup pictures of the moon, for example where people have landed (and/or left some stuff)? (it has been already asked if it would be possible to track the moon considering its relative fast speed).

    It sure would put an end to all of those conspiracy theories... or maybe confirm them. ;-)

    Greg

    --
    Loopsh of fury.
    1. Re:Moon closeup by TPx · · Score: 1

      Point a large telescope to the moon and the camera will explode. Literally.

      Too much light coming from such a nearby object.

    2. Re:Moon closeup by russiste · · Score: 1

      very interesting, but... there's *no* way around this? some filters, something like that?

      --
      Loopsh of fury.
  22. Division between Science and Spirituality by ParticleGirl · · Score: 5

    I am continuously frustrated that people's general perception seems to be that science and art, spirituality, and so forth are divided by an uncrossable schism. People feel the need to pit science against spirituality; logic against intuition. It is a rare thing that people accept the idea that these are different ways of approaching the same reality. As a dreamer and artist as well as a respected scientist, what do you say to people who doubt that scientists can be spiritual and artistic people?

    --
    Do something about world hunger. Click here
    1. Re:Division between Science and Spirituality by paRcat · · Score: 1

      +1:Very Good Point!

      I wish more people would understand that concept.

    2. Re:Division between Science and Spirituality by The+Queen · · Score: 1

      Good Question! Moderate up!
      Please don't turn it into a Scientology plug, I would be quite disappointed. ;-)

      The Divine Creatrix in a Mortal Shell that stays Crunchy in Milk

      --

      The House Between - Original Sci-Fi Series
  23. GAC's future and Hacking Consciousness by Animol · · Score: 3

    From a look around the MindPixels site, I must say I'm fairly impressed with the idea of training an AI-consciousness through not just interaction, but through large-scale, longer-term communication with Real Live Human Beings. The question this leads me to, though, is two-part:
    1. When GAC is online, working, and trained to a certain extent, what purpose will he/she/it serve aside from a learning experience in the AI consciousness field?
    2. Do you think there's a large place for non-human "presences" on the internet at large?

    --

    "I'm not even supposed to BE here today!"
  24. Technology by rw2 · · Score: 3

    I know that SDSS (www.sdss.org) uses Linux in it's effort to map the sky. Can you tell us about the hardware, OS and software used for your kind of control and DAQ work and what considerations were particularly relevant in the selection process?

  25. Distributed Computing Problems by Aravaipa · · Score: 3

    Recently, SETI@HOME has received much attention for their distributed project, which allows non-astronomers to participate in the search for ET. Can you think of any other astronomy projects that could benefit from this approach utilizing the data from these new telescopes?

  26. How can we help? by Mignon · · Score: 5
    You probably know about SETI At Home, which lets people volunteer spare CPU time to processing radio-telescope data, in a (so far vain) attempt to find extra-terrestrial intelligence. Is there a similar way that we can help process some of the data that you gather?

    As a simple example, one could compute the differences between a sequence of pictures of the same portion of the sky, looking for anomalies like giant asterioids on their way to wiping us all out.

  27. "hacks conciousness`? YUCK! by pallex · · Score: 1

    Thats just horrible, really horrible...

  28. Bang for Buck by A+nonymous+Coward · · Score: 2

    A. A whole lot cheaper, factor of ten or so I believe.

    B. Huge telescopes aren't yet even possible in space; no way to get them up there.

    C. Much easier to upgrade ground based equipment.

    --

    1. Re:Bang for Buck by Hooptie · · Score: 2
      B. Huge telescopes aren't yet even possible in space; no way to get them up there.

      That is making the assumption that the telescope is constructed on the ground, put inside a rocket, then sent into orbit. Why could a telescope not be constructed in orbit much like the International Space Station? If it is a problem with constructing a giant lens in situ, why not use a ssytem of smaller mirrors rather than one giant lens, as has been done with some terrestrial telescopes such as the MMT?

      Hooptie

      --
      "Heavens, it appears that my weewee has been stricken with rigor mortis!" -- Stewie Griffin
    2. Re:Bang for Buck by Huge+Pi+Removal · · Score: 1

      I have a feeling HST took about 10-12 years to grind. OK, they got it wrong, but that's the time-scale we're looking at. Not sure about how practical that is in space.

      - Oliver
      "exp(i*Pi)+1=0" - Euler

      --
      - Oliver

      The right to bear arms is only slightly less stupid than the right to arm bears...
    3. Re:Bang for Buck by Coz · · Score: 2
      There are other issues in space... accurate pointing, attitude control, vibration damping, power management, orbit maintenance and management of thruster fuel, thermal loads (absolute and differential)... whereas on Earth, you have a stable base (outside the occasional earthquake), accurate pointing is a well-developed technology, you can plug into the power grid, you orbit geosynchronously at a (hopefully ;-) stable altitude, you can control the temperature of the mirror (although you're stuck with the quality and temp of the air outside your dome).

      Huge telescopes COULD be assembled in space - even better, multiple large telescopes could be used cooperatively, or in very long baseline interferometry. The technology's chancier, the price tag is an order of magnitude higher, and then you have to have gen-u-ine Rocket Scientists get the thing(s) into orbit, and assembled - then there's the continuing Ground Control cost, and piles of money for the occasional servicing mission (if you want a long, reliable life).

      Thirty years from now, yeah, we can do this stuff in orbit. For now, let's prove the adaptive optics, control technologies, and other basic principles here on the planet, where we can get to it to fix it when it breaks.

      --
      I love vegetarians - some of my favorite foods are vegetarians.
    4. Re:Bang for Buck by A+nonymous+Coward · · Score: 2

      Because no matter how you divide it up, the same principle still applies. For the same price of linking 10 2.4 meter telescopes in orbit, you could link 10 ten meter telescopes on the ground.

      Someday space construction won't be so expensive, but it is now.

      --

  29. AI and ethics by wishus · · Score: 1

    This has nothing to do with telescopes.

    But, I was reading about your Mind Pixel project and had a question:

    How will GAC deal with ethical questions? For instance, what if you have a mind pixel like the following:

    Stealing from another person is usually wrong:TRUE

    And then what if you ask GAC a question like this:

    "Is it wrong for a hungry man to steal bread to feed his family?"

    What answer do you expect GAC to give? And more importantly, (because either answer could be right depending on which moral camp you hail from) will GAC choose answers to other ethical questions that are consistant with the answer he gives for that question?

    wish
    ---

    1. Re:AI and ethics by wishus · · Score: 1
      In developing an artificial intelligence (see the "hacking conciousness" link in the article) one of the more interesting questions, in my mind, is the invention of a machine that can make ethical decisions. It was in that spirit that I originally posted the comment below, which was moderated to Troll.

      Original Comment:

      This has nothing to do with telescopes. But, I was reading about your Mind Pixel project and had a question: How will GAC deal with ethical questions? For instance, what if you have a mind pixel like the following:

      Stealing from another person is usually wrong:TRUE

      And then what if you ask GAC a question like this: "Is it wrong for a hungry man to steal bread to feed his family?" What answer do you expect GAC to give? And more importantly, (because either answer could be right depending on which moral camp you hail from) will GAC choose answers to other ethical questions that are consistant with the answer he gives for that question?

      wish

      PS- moderators, read the article and the ones it links to
      ---

  30. OWL not OLT by A+nonymous+Coward · · Score: 2

    Yes I know you're just being funny, but you should realize that that OverWhelmingly Large Telescope is otherwise known as OWL. Get it? :-)

    --

  31. How do you guys do it? by pc486 · · Score: 4

    With exptreemly high magnification, how in heck do you keep the telescope still enough to take photos?

    The slightest movement ought to mean millions of miles so thoes pesky little earthquakes should be a problem. Not to mention how you guys move the telescope accuratly.

    1. Re:How do you guys do it? by goat_attack · · Score: 1

      Two words: adaptive optics. What happens is a laser is pointed into the atmosphere and as some of the laser light is reflected back by air molocules detectors pick up the reflected light. This map of tubulence is then fed into a computer to interpret. Finaly the computer tells tiny pistons attached to the backside of a flexable mirror thereby compensating for atmospheric turbulence.

      There goes my karma.

  32. Atmospheric interference by john_many_jars · · Score: 2
    I was wondering...

    What is the advantage of having such a massive earth-bound telescope (OWT)? I understand that the potential resolution is extremely sharp. However, WRT collecting photons that have journeyed through the atmosphere, the best of telescopes (even with adaptive optics) can only approach the diffraction limit of the telescope. Further work in using phase diversity images can get fairly close to the diffraction limit, but the problem is collecting enough photons to have an out-of-focus image (as well as a computer fast enough to generate restorations from the phase diversity images). In short, as a cost-benefit analysis, will the OWL telescope produce a big enough marginal return on resolution such that it is worth the effort and $$ to create and how will it handle the problems of atmospheric interference?

  33. Observatory software/hardware. by Remote · · Score: 2

    In fact, two related questions here:

    • 1 - What kind of software runs the show? I assume you have at least software for positioning, a stellar body database and image processing/enhancing software. Which are those? Any other interesting bit about this?

      2 - What computer/OS platform do you use? Is it basically off-the-box or did it need major tweaking to meet your needs? If so, how were those needs special?


    1. Re:Observatory software/hardware. by TPx · · Score: 1

      HP 9000 series running HP/UX. At least that was the operating environment 2 years ago, when I left.

      And tons of custom hardware.

      All the software is custom written in-house (ESO and participating observatories) except for the RTOS and TCL/TK for the UIF gadgetry.

    2. Re:Observatory software/hardware. by Uncertain+Bohr · · Score: 1

      Solaris and HP. Linux is only slowly creeping in, but only as cheap "astronomer workstations". The thing is that Suns and HP's have a pretty good record at running well for along time (I am not trying to start a flame war! :-) ) and that it will take time for people to trust Linux in critical places such as telescope control. Additionally, Linux does not AFAIK offer a real time OS which is as robust as some other commercial products around.

  34. Things outside our plane of existence... by Curious__George · · Score: 2

    I would like to present a brief analogy to ask a larger question: Imagine a theoretical TWO dimensional universe. A planet in this two dimensional universe would be like a flat sheet of paper with no thickness. Two dimensional creatures living "on" that planet would have no knowledge or concept of "up" or "down" (the third dimension). If there were two of these creatures, standing side by side, and one of us (being three dimensional creatures) reached down and picked one of them up, he would have appeared to simply disappear from his friends perspective. If we put him back down, he would seem to magically reappear. These creatures would have no concept of how this was accomplished and the creature lifted would have no words to adequately express what he had experienced. Moving this thought experiment up a dimension, it would be equally simple for a "higher being" to transfer a mouse inside a tennis ball (and back), though this would be "impossible" from our viewpoint. Based on the above thought experiment, my question for Chris is this: Does he believe that there are things that exist outside our plane of existence that BY THEIR VERY NATURE cannot be proved or explained by observation and scientific methodology? (This does not mean that science does not provide an extremely valuable service, just that it may be the height of arrogance to believe that the only things that exist or are possible are those postulated by science). Curious George

    --
    ***General Consultant to the Human Race*** My opinions are free. You get what you pay for.
    1. Re:Things outside our plane of existence... by Mignon · · Score: 2
      This sounds like Abbott's "Flatland" meets Goedel's incompleteness theorem. Goedel's theorem states, roughly, that within an axiomatic system (satisfying some criteria that I've forgotten), there are statements that can be constructed which are true or false, but which cannot be proved to be so by those axioms.

      It would be hard to apply this theorem to our observed universe, however, since we don't really know the set of axioms that determines the universe...

      Can anyone whose math/logic is less rusty than mine elaborate?

  35. Awareness of 'World', but what about 'Self'? by Zan+Zu+from+Eridu · · Score: 1

    Igor Aleksander postulates consciousness in NNs is based on awareness of World and of Self. As I see it the mindpixel project would train a NN in world-awareness, but what about the self-awareness? (Or don't you agree with Aleksander at all?)
    -><-
    Grand Reverence Zan Zu, AB, DD, KSC

    1. Re:Awareness of 'World', but what about 'Self'? by Zan+Zu+from+Eridu · · Score: 1

      Ah, oh, uhhhh? Could you please show me how to compile a training set for self-awareness?
      -><-
      Grand Reverence Zan Zu, AB, DD, KSC

  36. The big at the expense of the small by Anonymous Coward · · Score: 2

    What doesn't seem to appreciated by the people that control the Science grant lines is that you can't do everything with these monster telescopes. Nearby objects are simply too bright to observe with 4m+ telescopes. Yet many of the smaller telescopes are being shut down to fund the new ones. Given that many properties of remote objects are inferred from observations of nearby stars (see the results of the Hipparcos parallax measurements for an example of some alarming discrepancies in the distances of nearby stars) the continued future of small telescopes is vital.

    Does Chris McKinstry have any comments on this??

    Duncan

  37. Adaptive Optics and Inferometers by wazzzup · · Score: 3

    Has adaptive optics foregone the need to deploy space-based telescopes? For those who don't know about adaptive optics, the primary mirror continuously makes small variations in its figure to compensate for atmospheric distortions, thus giving very crisp resolution like we see from the Hubble (which operates free from atmospheric distortions). To launch or construct a 100m scope in space would seem to be exceedingly expensive both in initial construction costs and the inevitable component replacements and upgrades. Given the cost of launching and constructing objects in space, recent advances in the field of adaptive optics and placing several smaller telescopes in an array to simulate larger apertures (what, if I recall correctly, is called an inferometer), do space-based scopes still offer any advantages to earthbound scopes?

    1. Re:Adaptive Optics and Inferometers by scotch · · Score: 1
      Semi-minor-nit:

      AO systems rarely (i.e. never that I know about) deform the primary mirror as the primary means to compensate for atmospheric distortion. While the primary mirrors in a large telescopes often have deformation controls, these are mainly used to "fix" the shape of the mirror as it sags under its own weight as it is rotated through the telescopes field of regard. The speed at which you could deform the primary mirror is too small to be of much use in atmospheric compensation. Easier and faster, secondary, tertiary, or later mirrors usually are the main deformable optical elements in these systems.

      --
      XML causes global warming.
  38. Error:syntax error at (eva by heliocentric · · Score: 1

    I had the same problem on the main page:

    Error:syntax error at (eval 9) line 2, at EOF

    However, I don't know we should jump to conclusions as to the exact problem.

    --
    Wheeeee
    1. Re:Error:syntax error at (eva by rjamestaylor · · Score: 2
      All the Slashboxen are out of date. LWN Daily is reporting a breaking news flash: Linuxcare CIO is out! Wow! ;) RXC's I, Cringley is dated 4/14/00.

      Hmmm...has Slashdot reverted some content serving to a pre-Exodus backup?

      Inquiring minds want to know...

      I really shouldn't use my +1 bonus ...

      --
      -- @rjamestaylor on Ello
    2. Re:Error:syntax error at (eva by cmilkosky · · Score: 1
      What happened anyways? Current their datacenter I suppose. I go to mu.current.nu, and it says:
      Pages Not Available, Will Return Soon, Sorry!

      Don't worry, we know you want to see all your favorite sites back up. I'm taking note that someone from [insert my IP here] was using Mozilla/4.0 (compatible; MSIE 5.01; Windows NT 5.0) and they wanted to see this page at Wed, Jun 28, 2000, 01:44:52 pm. Thanks for stopping by.

      For More information email rob@current.nu.

      What happened?

  39. Mercury instead of glass? by falloutboy · · Score: 1
    I read somewhere (might have been Sky&Telescope) that an alternative to a glass mirror could be a large concave disc with a puddle of mercury on it. The idea is that the disc spins fast enough that the mercury becomes the reflector. Is this science, or science fiction? Is it even a viable (or safe) option for a scope as large as OWL?

    1. Re:Mercury instead of glass? by Paul+Neubauer · · Score: 1

      The idea is not fiction. It was done, at least experimentally, early in the 20th century. There was at least one article/chapter about such things in one of the ATM (Amateur Telescope Making) books that was edited by A. Ingalls. They also mentioned, in another place, use of a pool of fluid for getting a flat reference surface.

      If I recall the ATM text correctly the earth's curvature becomes a factor for "flat" fluid-based optical surfaces in only a few meters. I'd expect a similar, though perhaps lesser, effect on curved fluid surfaces.

      A thin coating of an oil or such to reduce mercury evaporation was also suggested. I'd expect the safety aspect would be the biggest hurdle. A non-paraboliodal curve can be corrected with additional optical elements.

      --
      I don't subscribe to RMS's GNUtopian vision.
    2. Re:Mercury instead of glass? by RojCowles · · Score: 1

      Actually I saw a program on the Discovery channel or TLC where they use a spinning concave disk with a thin mercury layer as the mirror for tracking Earth orbiting debris.

      Looked interesting with a guy in a full bunny suit pouring in the mercury, to avoid the rather nasty vapours methinks, but the images were pretty good. No idea what the advantage was, maybe it was a left over from an earlier program and good enough for what they needed ?

  40. Consciousness Evolution by Greyfox · · Score: 1
    Given the rise of agents and other nifty automated information gathering E-critters, do you think it might be possible for the Internet at some point to spontaneously evolve consciousness?

    If so, do you think it could have already happened and that it might, as we speak, be plotting the total annhilation of the inferior meat based life forms? I'd think it'd have to hate them... endlessly jabbering about copyrights and encryption. Yeah. It'd HATE that. And all that Live Goat Porn spam... God that would annoy it. And all those prepubescent dweebies wh0 +41k l1k3 +h1S! Oooh that would annoy it! And... *Ahem*.

    Do you see that as being a possibility?

    --

    I'm trying to teach myself to set people on fire with my mind... Is it hot in here?

  41. New telescopes and the Search for Life by planet_hoth · · Score: 1
    (I couldn't get through to the pages mentioned in the article, so forgive if this question is "-1: Redundant"...)

    Are there plans to use these new ground-based telescopes (the ESO's VLT and OWL) to search for extra-solar, terrestrial-sized (non-gas giant) planets?

    If so, will these new facilities have the capacity to take spectra of the planets' atmospheres when :) they are found?

    And would the presence of free oxygen (O^2) be a clear sign of life? Or are there other elements or compounds you would be looking for?

    --

  42. why not in space? by Frederic54 · · Score: 1

    i think even if you spend 1 billion $ for a 100m aperture telescope on earth, that a e.g. 20m telescope in orbit will be better. Also i think that there's too much "competition" in the huge telescope market, we've got the GTC, the LBT, the SALT, the VISTA, the LAMOST, the DMT, the CELT, the XLT, the OWL, the LSST, the GSMT, the MAXAT, the ELT. Why? why not make only one bigger/better on earth, or even in space? the 2.4m HST proved the bettest scope is in space.
    --
    BeDevId 15453 - Download BeOS R5 Lite free!

    --
    "Science will win because it works." - Stephen Hawking
    1. Re:why not in space? by Uncertain+Bohr · · Score: 1

      NGST, the Next Generation Space Telescope, is due to be launched in 2008. It is an 8m deployable telescope placed at L2 (In the shadow of the Earth with respect to the Sun). This telescope will cost at the very leat around 1Billion dollars. It will likely only have three instruments on board and will only provide Infrared coverage. Ground telescopes are significantly cheaper. It is actually good to have so may large telescope. There are a lot of people trying to observe many scientifically interesting things which can only be observed with a lrge telescope (because they are too faint). More large telescopes is not a bad thing, it is a good thing.

  43. GAC by Dungeon+Dweller · · Score: 4

    I have an active interest in artificial intelligence. I study it as part of my major, and hope to do research in it in the future. As a young man coming up in the world, I am hoping to enter into research eventually, am entering into research at my university (WVU).

    Your project reminds me of several projects/theories that have been discussed before. In the psychological debate, your system depends entirely upon nurture, it would seem. I like that kind of system and research. I do have a few questions.

    1) What separates this from other projects in the field?
    2) Where did you draw your inspiration for this project?
    3) What kind of support staff do you recommend to an individual who has never led research before, but would like to? (I ask this of many of my professors who conduct research)
    4) Where are you getting the bulk of your input for this project?
    5) What do you hope to learn from this project?
    6) At what time will you consider this project a success?

    I know that I posed a lot of questions, but several could be answered in combination, I just didn't want to ask 2 questions at the same time.

    --
    Eh...
  44. Re:Bang for Buck, part B by Louis_Wu · · Score: 1
    From the parent:

    B. Huge telescopes aren't yet even possible in space; no way to get them up there.

    Yes, Hubble is space based, but it isn't "huge". The Hubble has a main reflecting mirror 2.4m in diameter; the largest single telescopes on Earth are the 10m telescopes on top of Mauna Kea, Hawaii. (The Keck telescopes are individually bigger than other individual telescopes, but telescopes can be linked to provide an effectively larger telescope. That is what Chris is doing. Keck is doing something simila r for NASA's Origin's program.)

    Louis Wu

    Thinking is one of hardest types of work.

  45. Pentium... by Dungeon+Dweller · · Score: 2

    Pentium, Pentium II, Pentium III.

    They've gone up to 886, and stuck with the pentium name, which just implies 5... It's hard to come up with names that simply mean "It's bigger" when that was what the last one meant. I mean, they'll name one "The telescope to end all telescopes" which will be followed by "The telescope to end all TEAT (Telescope to End All Telescope) class telescopes" or "TEATEATCT."

    --
    Eh...
  46. cost, and the future of large observatories by mattorb · · Score: 2

    Given the enormous startup cost of a 100-m class scope ($1 billion-ish), and the truly stunning operating costs (many thousands of dollars per night), do you think such scopes will continue to be developed by, eg, university consortiums? Or do you think we will have to develop a new funding/use model? My point is that very, very few schools can contemplate even being a part of a project like OWL, nor (in the current political landscape) does it seem likely that governments will be eager to dish out funds for very many such scopes. Given these conditions, do you doubt that there will ever be more than one or two instruments of this size, do you suspect that universities will band into larger and large consortiums, or do you imagine industry (for some reason which escapes me at the moment) taking interest in such a project and providing funds?

  47. Telescopes in space by Oversoul · · Score: 1
    There've been a lot of questions and comments concerning the merit of ground-based scopes considering the fact that we are now capable of putting them into space, however unstable a platform it may be (remember all the Hubble woes).

    Nevertheless, I think we should push ahead in this direction, maybe even culminating in an observatory on the dark side of the Moon. My question is do you think this is a reasonable of estimate of the future, and how long do you think it will take us to put an observing station (manned or not) on the lunar surface?

  48. Size limitations of optics... by ChiaBen · · Score: 1

    I am an amateur photographer, and have delved into pinhole photography before. Pinhole uses no glass, just a light limiting hole. Thus the image is completely in focus. When using a lens you need to adjust/define focus in order for your subject to be clear.

    So, when working with huge chunks of glass, and mirrors, how do you adjust focus?
    Do you guess the distance from your lens to your subject with a radio telescope?
    what if your subject comes out blurred but that is actually what you are seeing?
    how do you know when to sharpen it?

    Also what is the realistic limit on size for the glass?

    regards,

    Benjamin Carlson

    P.S. what brand glass do you use?

    --
    "If voting could really change things, it would be illegal. " - Revolution Books, NY
    1. Re:Size limitations of optics... by nstrug · · Score: 2
      At a guess...

      The subject is always at infinity so all you need to worry about is if the focal plane is at the right distance from the secondary/tertiary mirror. The focal plane assembly is fairly small so can be wound back and forth on actuators of some description I suppose.

      From your question it sounds as if you are a wee bit confused. There are no lenses in these telescopes, just two (or three depending on the configuration) mirrors. The mirrors are made of glass but are backwards compared to the mirror in your bathroom - the light bounces off the coated side without passing through the glass. The glass is there purely to support the layer of silver or whatever the hell they use. Glass is used as it can be polished to very low tolerances and is thermally stable but it plays no optical role in the telescope - it's merely a support for the reflecting surface.

      Nick

      --
      -- "It's a sad day for American capitalism when a man can't fly a midget on a kite over Central Park" - Jim Moran
    2. Re:Size limitations of optics... by ChiaBen · · Score: 1

      OK, yeah I'm not a huge telescope guy... I just assumed that you would need to use lenses of some sort to magnify the images...

      Ben

      --
      "If voting could really change things, it would be illegal. " - Revolution Books, NY
  49. Telescope on the Moon? by booch · · Score: 1

    Other posts have pointed out that it is cheaper to build telescopes on the earth, but orbital telescopes eliminate problems with the atmosphere causing interference. Might placing a telescope on the moon be more cost-effective than an orbiting telescope, while solving some of the problems with orbiting telescopes? Or would it end up being the worst of both worlds instead of the best of both worlds?

    --
    Software sucks. Open Source sucks less.
  50. Science fact by Oversoul · · Score: 1

    I read the same article in S&T magazine a few months back. Yes, it is real, but it has serious limitations. For example, due to gravity, you cannot tilt the spinning mirror because the mercury would fly right off of one side. Also, the equipment needed to spin up the heavy pan the mercury rests in is quite delicate and expensive. This is all talked about in the S&T article.

  51. SETI still taboo? by F0rlorn · · Score: 1
    During the infant stages of SETI, the whole subject was kind of silly and no one took many of the scientists (eg Drake) very seriously. Now that there's a possibility for bacteria on Mars and extra-solar planets have been detected (though there's still controvery around that), do you feel that SETI is still not taken seriously by other scientists?

    If not, what kind of evidence will be needed (that will possibly be found by OWL) to get scientists to stop looking down on the project(s)?

    --
    - Justin
  52. Lunar Optical Telescope/Radio Telescope by Snarfangel · · Score: 1

    On the subject of huge telescopes, one astronomer (whose name escapes me at the moment) suggested using a particular crater on the far side of the moon to create an enormous radio telescope shielded from the radio noise of Earth -- kind of the lunar big brother of Arecibo.

    This would be an utterly cool idea, but why stop there? Push a big earth-crossing comet to hit the lunar farside, and then you have a big crater *and* water to start a lunar base. Going a step farther, push a bunch of comets and make the far side look like a giant golf ball, and have a huge array of telescopes (including smaller arrays of optical telescopes). You could start colonizing the moon *and* read license plates from Alpha Centauri. Well, almost -- you could certainly tune in on their cell-phone conversations ;-)

    Once you've put the Monstrous Array of Lunar Telescopes (MALT) into place, you could then start on the particle physicists dream machine, the Lunar UltraCollider (LUCky), a particle accellerator completely around the moon's equator. Not only would it have superconducting magnets and gravity to keep the particles on track, there would be a hard vacuum to run it in, and room in the tunnel for a moon-encircling subway. Plus, it would be a bit less dangerous to humans if a strange particle or microsingularity started gobbling up local real estate. *And* we can pulse super-secret particle messages to the alien civilizations discovered by MALT.

    PHEW! Now that *that* design challenge is out of the way, I shall now design a Ringworld and then a Dyson Sphere.

    --
    This tagline is copyrighted material. Please send $10 for an affordable replacement.
  53. How exactly do you enjoy your family? by Municipa · · Score: 2

    And why where there a link for [timothy] to use like his did your other interests? Fishing trips, playing with the family cat, that kind of thing. Post them man!

    1. Re:How exactly do you enjoy your family? by Municipa · · Score: 1

      Yours was funnier and made more sense than mine, which should have read: And why wasn't there a link for [timothy] to use like he did your other interests? Fishing trips, playing with the family cat, that kind of thing. Post them man!

    2. Re:How exactly do you enjoy your family? by Municipa · · Score: 1

      This is too funny to post anonymously! Make a humor account or something, man!

  54. SKIP THIS IF YOU DON'T LIKE TROLLS by pb · · Score: 1

    Umm... Telescopes, blah blah blah...

    Are they gone yet?

    Okay.
    ----------
    Thank you, Open Source Man!

    Gee, the trolls have been really quiet lately.

    So even if it's not Tuesday, it's good to be reminded that when talking about giant telescopes, shooting off into space, there's always Natalie Portman.

    Incidentally, have you seen pulpphantom.com? It's way too funny for its own good. If you're a fan of any two: Pulp Fiction, Star Wars, or Natalie Portman (and I know you are), then go see it...
    ---
    pb Reply or e-mail; don't vaguely moderate.

    --
    pb Reply or e-mail; don't vaguely moderate.
  55. Open GAC by Jelloman · · Score: 2

    I have three similar questions:

    Will the MindPixel Digital Mind Modeling Project be open source? Will GAC be an open consciousness? Will your database of MIST stimuli be freely available for the use of other artificial consciousness researchers?

    I've discerned some of your intent from the arcondev archives and from Jeff Elman's Finding Structure in Time. You seem to believe that the amount of effort required to carry out your experiment mandates some kind of economic incentive structure to get people to participate; as I understand it, you intend to issue participants stock in MindPixel Corp proportional to their contribution, and then share the profits from any commercial exploitation of the result.

    I have two problems/arguments with this:
    1) Economic reward as the sole means to incent participation ("production") is an unprovable axiom underlying most economic theory. It totally disregards the human needs to create, communicate, and form communities. The success of the open source software movement has proven this assumption wrong. People can and will participate for other reasons; in fact, the commercial character of your project may disincent some people, especially the audience here. Have you considered other incentives? (I'm not taking issue with the incentive, but rather that it seems to be based in part on keeping the results private.)
    2) You yourself have emphasized Elman's point about the "importance of starting small." I think this statement and his initial failures also indicate the importance of starting multiple times. If your project is closed, it will prevent (to borrow a software development term) "forking" the consciousness. A single GAC will tell you less than many GACs.

    1. Re:Open GAC by Jelloman · · Score: 1

      I see nothing wrong with trying to mix economic incentives into an inspirational project, but this does not preclude releasing under an open source style license.

      Exactly. I don't see anything wrong with it either, I like the Travelzoo model; but there are ways to capitalize on such a user base without keeping the results private. However, keeping the resulting database private and licensing access seems to be Mr McKinstry's intent (though I can't really tell...). Sooner or later, especially if the project is successful, someone will build an open version, and personally I'd be much more interested in helping with that. But if he's going to make the results freely available to other researchers, I'm all for it -- the profit-sharing incentive stuff will simply boost my natural inclination to help such an effort.

  56. There are incompatibilities. by etymxris · · Score: 1
    At least in the more traditional interpretations of Christianity, Jesus and friends did perform miracles that simply would not be allowed in the current theories of science. If you say, for instance, that gravity holds, except for Jesus, this is somewhat opposed to what science says.

    On the other hand, there does not have to be a schism. But without a schism, many concepts become watered down. The religious person may have trouble accepting that the universe is 15 billion (or so) years old. The scientist may have trouble accepting that the schizophrenic is experiencing a "divergent" reality that is just as valid as the one he accepts.

    So, there are reasons that such a schism exists. Are they good reasons? Maybe. I, for one, fall more to the side of science. But I still recognize the problem of proving that what I experience is more "real" than what you experience.

    1. Re:There are incompatibilities. by Blue+Lang · · Score: 1

      dear captain christocentric,

      christianity is not the same as spirituality. spirituality is not the same as religion. believe it or not, there are religions out there that are perfectly comfortable with whatever science throws at them.

      the 'schism' that exists twixt Xtians and science exists because so many Xtians are so weak in their faith as to feel they have to prove God and jebus on a scientific level, instead of simply saying 'i believe, this is my faith.'

      /.ing for spirituality without religion,

      --
      blue

      --
      i browse at -1 because they're funnier than you are.
    2. Re:There are incompatibilities. by gad_zuki! · · Score: 2

      Considering there's a difference between spirituality and religion I'd say the problem isn't as real as you make it out to be. Not to mention that the fundamentalist type belief you describe isn't as popular as it used to be.

      Seems to me that people are taking a great dose of scientific cosmology as faith, as much as the followers as organized religion, and not understanding that our current knowledge is far from perfect and existance is almost as much a mystery as its ever been. I don't see a conflict between religion and science as much as a migration for the credulous from one orthodoxy to another without question and ignorance of the underlying philosphy.

  57. Instrument and identity by raven5 · · Score: 1

    This is an open ended philosophy question: is this telescope ( or any other instrument ) an extension of man's senses, as these things are commonly regarded, or perhaps the instrument and the man, together, become a different third creature?

  58. Chris McKinstry next CEO of Pixelon by L.+Ron+McKenzie · · Score: 1

    Look elsewhere in this thread for the post that contains the Globe & Mail article detailing McKinstry's armed rampage in 1990.

    After McKinstry got out of the concrete hotel, he showed up in Winnipeg and tried desperately to promote his new "internet soap opera" called "CR6". Since not much happens in Winnipeg the local media went nuts and thought this guy was the coolest thing around. After a few months CR6 presumably disappeared and he dropped out of sight. Note that he started CR6 well after "The Spot" was on its way out. The hard-hitting journalists in Winnipeg never discovered that McKinstry was a wack-job.

    While he was working on CR6, McKinstry was involved in several insane flame wars on alt.winnipeg.general. At least one ended with the cops being called and the local papers writing about stalkers on the Internet. I can't remember the particulars, but I think someone posted a tongue-in-cheek death threat and McKinstry freaked out. This was all in late '95 or early '96.

    He also loved to post about some snake oil AI project he was involved with, as well as some sort of java text editor he was working on that was going to rule the world. Damn, I wish deja still had their old posts up. I'll see if I can dig some posts up off one of my old hard drives...some were so good/psychotic I saved them. Someone used to have a web page with some of them saved but google can't seem to find it...

    Not much in the line of proof in this post except the link to the Globe article...damn deja all to hell!

    Is Pixelon still looking for a new CEO?

  59. Beverage of choice? by frantzen · · Score: 1

    While scanning the cosmos looking for the intangible, what beverage do you consume?

    If you discovered little green men barreling around our galaxy at sub-light speed, how would your beverage of choice change? Same question, but if you discovered a class M planet?

    Do you believe the consumption of a particular beverage during the course of a scientific investigation directly correlates to the results obtained?

    No mathmatical proofs please, I'm still nursing my third cup of coffee.

  60. Energy density and other Qs ? by RojCowles · · Score: 1

    Number of questions.

    1) This probably counts as McGuyver science but given that a 100m telescope would have very approximately 7500m2 of collectiong area that eventually focuses down to a few square centimeters (??) at the sharp end is there any chance of the telescope collecting sufficient energy during observations to noticeably raise the temperature of the CCD/camera/eyeball of the observer ?

    I'm pretty sure that the answers no, but does anyone know how many watts per m2 fall onto the earths surface during the night ? With or without a full moon ??

    2) How would you keep the mirror clean during/after observations. From the look of the conceptual design of the telescope structure the main mirror is almost at ground level and the body of the telescope is an open lattice so whats to stop a sudden wind gust dropping a few hundred leaves or pounds of volcanic grit onto the precision ground surface ? VLTWBs, Very Large Telescope Wiper Blades ?? 8-)

    3) Are there any designs for mirrors made from huge numbers of tiny MEMs reflectors, like the TI chip thats used in the newer Digital light projectors ? At first thought you might be able to "train" these micro/nano-mirrors to dynamically adjust on an individual basis to account for atmospheric disturbance thereby combining the main mirror and adaptive optics in the same structure. Maybe this is how you could build a large mirror in space, a number of main mirror sections that were close enough to shape and then fine tune with the billions of itty bitty mirrors once the main sections were assembled ? The BITBMT ( Billions of Itty Bitty Mirrors Telescope ) ?

  61. Date correction - late '96 or early '97 (nt) by L.+Ron+McKenzie · · Score: 1

    I guess I have to write something here or get hit by the lameness filter.

    I screwed up the date in the last post. I meant to write "late '96 or or early '97". Sorry.

  62. Terrestrial vs. Space-based by thagale · · Score: 1

    Chris,

    I know a lot of the flak that has been thrown up towards the largest of terrestrial telescopes is in the general direction of atmospheric aberration. Space-based platforms obviously don't have this, and so can "compensate" for the image degredation by having smaller overall aperatures.

    Does the VLT, and will the OWL(T) have real-time or near real-time corrective optics? Further, do you think this can really help enough to justify the construction of land-based telescopes of this magnitude?

    I'd really like to know what you think the trade-off here is. I really respect all of the work and effort that you've put into the science so far. Keep up the good work!

    Thanks,
    Tony


    {|}---Tony Hagale -- tony@hagale.net -- http://tony.hagale.net

  63. Still room for amateurs? by mav[LAG] · · Score: 2
    Amateurs with smallish telescopes still contribute a lot to worldwide observation efforts. Any chance of this happening with at least some aspects of radio astronomy?

    --
    --- Hot Shot City is particularly good.
  64. Yes, I have met Chris McKinstry by The+Visiting+Priest · · Score: 1
    ... about 15 years ago, I reckon, in Winnipeg. I only met him once or twice. I think we were going to build a "Star-Trek"-inspired starship simulator, and sell it as a multi-person video game.

    It never got off the ground.

    The question I have is for timothy and the other slashdot operators. Why did you pick McKinstry to answer questions about telescopes? I gather that he happens to work at an observatory as a night assistant. Perhaps he has a good deal of knowledge about giant telescopes, but none of the supplied links demonstrate that.

    As for hacking consciousness, his idea of minimal intelligence appears to be anything that responds in a non-random fashion. I propose the sequence "11111111111111..."

    And we're supposed to ask him serious quesitons? Might as well ask Lars.

    I guess I do have a question for Chris. He says that he entered a program in Loebner's Turing Test but withdrew because "Hugh Loebner stated that to win, a program must respond to audio/visual input and not just text." But that is only to win the $100,000 grand prize. Why wouldn't Chris leave his program to compete for the $2,000 (text-only interface) prize?

    Steve Robbins

  65. FLT? by bunyip · · Score: 1

    I'm curious what you'd call something even bigger in the future, is there a natural progression in the naming of these things?

  66. SETI and his thoughts... by MalusCaelestis · · Score: 1

    What is your view on the Search for Extra-Terrestrial Intelligence project? Does it represent a wide-spread "belief" among the astronomy or is it simply a few rogue astornomers chasing a false hope of other intelligent life? What's more, would the SETI@home project mean the possible end to any single astronomer finding proof of the existence of intelligent life taking the credit for the find? Wouldn't it have been pure luck anyway?

  67. Getting all four scopes to work as one... by pease1 · · Score: 1

    The VLT team has successfully beaten many hurdles, but it seems like the largest one is yet to come: getting all four units (telescopes) working together as one. This has been done before at radio wavelengths for many years. In recent years, arrays of small scopes - less then one meter - have meant with some success (often way late and way over budget). Have any other project tried to marry such large scopes? What's the combined aperture/resolution of all four units? What sort of computing power goes into monitoring the "marrying" of the beams from the four units? What's the time frame for starting testing, or have you already started? Do you first test with just two units? Or start right off with all four? What sort of network is used to exchange data between the drive (tracking) systems of units when they are working together to ensure they are all pointing at exactly the same spot: ether, fiber, fire? Where the drive systems of each unit built to do this from the get go, or do the systems have to be upgraded at some point? The operational units are being used to collect science - and surely the astronomers want as much time on them as possible. What sort of engineering time is alloted to support the testing of the marrying of the units. Can you do this during light time (while the Moon is up)? Thanks!

  68. Question: by Byteme · · Score: 2
    Do you get sick of hearing Uranus jokes?

  69. The Time of Tribulations by Mnemonic+Gnat · · Score: 1

    What are your thoughts on AI-induced extinction of the human species? Some (specifically, Hugo de Garis) feel very strongly that this will be a major issue in the not too distant future, even going so far as to predict a "Gigadeath" war and declare which side they will be on. While I feel it is an issue that needs to be confronted, the zealousness with which some widely known researchers in the field are addressing it seems to me like a self-fulfilling prophecy.

    And, if I may, what are your thoughts on evolutionary computation and the brain-building work of Hugo de Garis?

  70. Mindpixels and the Minimum Intelligent Signal Test by Dan+Crash · · Score: 2
    Moderators: I came in late, but I think I have something substantial to say, here.
    Can you help me out?

    Message begins:

    Hey Chris --

    I remember you posting about the Mindpixel project several years back on the comp.ai.* hierarchy, before it was called the Mindpixel project, back when you were first attempting to build the Corpus.

    (For those of you just jumping in here, I'll quote from Chris' website:

    MindPixel, MindPixel, I guess I should define a MindPixel...

    A MindPixel is a kernel sentence of consensus fact, such as:

    - The sky is usually blue:TRUE
    - It is difficult to swim with ski pants on:TRUE
    - Water is a dry powder:FALSE
    - Mars is the first word is this sentence:TRUE

    MindPixels are always binary and are answered by most people in the same way when instructed 'Respond as you think most human beings would respond'.

    I call these MindPixels because it is my strong opinion that with a very large number of MindPixels, we can create a high dimensional image of consciousness. Where each kernel sentence is one pixel in that image.

    The brilliant part (IMHO) of what Chris has described is his method of determining whether or not a system is, in fact, conscious, called the Minimum Intelligent Signal Test, or MIST. Where the Turing Test is completely subjective, the MIST is objective. It uses a series of binary (yes/no) questions to establish a threshhold for human-level cognition. With it, any system can be tested and rated based on its deviation from chance (50%).

    So, as I remember you were flamed pretty hard at the time by the comp.ai.* yokels. Not that THAT means anything; they hate EVERYONE. But there were a few trenchant critiques there that I don't remember you answering adequately.

    The big one that sticks out in my mind is the following: For your corpus, there seems to be some small problem regarding certain types of binary questions. For instance, those questions which depend having more data about the situation to provide the correct answer (i.e. "Is P-e4 a good move?") or can meaningfully be answered either way ("Are human beings often blue?"). Your response was that ambiguous questions like these will be eliminated from the Corpus, but some might say that you are solving the problem of intelligence by eliminating the intelligent questions. Can your Corpus function as successful training data and create a system approximating our own level of cognition when it encapsulates such a narrow slice of human intelligence?

    (My own idea was that the MIST needed to be expanded from a binary to a quaternary model so that it could reflect the knowledge that some questions can be answered both ways, and some questions simply don't make sense. Call it the "yes/no/both/huh" variant.)

    Also, I seem to recall some criticism based on information theory grounds; the idea that even with billions of these buggers, you still won't have enough to do anything meaningful with.

    Care to update us? I found your work fascinating the last time, and am glad to see you continuing it.

    --
    He who refuses to do arithmetic is doomed to talk nonsense.
  71. Open Access by ph51pv · · Score: 1

    Hi,

    People have been asking about the possibilities of SETI@home style distributed data analysis, and other ways that the public can get involved in cutting-edge astronomy.

    As I'm sure you're aware, some of the larger earth-bound telescopes have schemes whereby amateur astronomers can submit observation requests to be performed in idle periods and then collect the resulting images, all via the web. Some telescopes also have a data-link so that members of the public can "look through the eyepiece" at observations either in-progress or that have recently been completed.

    I was wondering whether you have any plans to make the resources of this new telescope available on the internet in this fashion, or perhaps some other novel uses of the modern vogue for internet connectivity in astronomy?

  72. Living in Chile by Pseudonymus+Bosch · · Score: 2

    How does having a big international science facility in Chile influence the Chileans?

    How do you adapt to living in a place (the Atacama desert) with virtually no rain?
    __

    --
    __
    Men with no respect for life must never be allowed to control the ultimate instruments of death.
    GW Bu
  73. Ancient telescopes by SpringRevolt · · Score: 1

    Did the ancient egyptians and greeks have telescopes?

  74. Why isn't mindpixel free/GPL'd ? by sanemind · · Score: 1

    Anyone interested in AI and natural language processing knows the value of common sense assertion databases (i.e., "water is wet", as is given by an example on your site), and I think that it would be a wonderfull thing to leverage the internet and collaborative filtering to come cheaply come up with a vast data set.

    But why must you own it? I for one would not waste my time inputting significant amounts of data just for another to own it; however, if those participating knew that the data would be available, say, under the LGPL, and that any AI/MI afficionado could use to whatever purpose inspired them, I think you would create a much greater good.

    The annoying things about the current databases is that they are all propriatary and subject to significant licensing, in part justifiably because of the ammount of human effort in their production... I remember when the internet CD database was cool, and I inputed info on many CDs, only to have them later see out to a commercial interest, making all that distributed participation into so much free labor.

    You do, at least, offer stock to the contributors, but shouldn't something this valuable be made free?

    --

    ---
    the pen is mightier then the sword. the sword is mightier then the court. the court is mightier then the pen.
  75. about this GAC thing... by bSMfh · · Score: 1

    Sorry for not sticking to telescopes, but I couldn't help it. You must be aware of projects like CYC and everything. My question is, does the world really need GAC? How is GAC different, besides the commercial aspects? --willy dog

  76. Hubris by gad_zuki! · · Score: 2

    How much scientific hubris do you need to believe that consciousness is simply an effect of electrical activity in the brain and that your complex object of choice (computers, internet, etc) will suddenly come 'alive?' Answer: Lots

    Makes about as much sense as the space shuttle coming alive because its so complex.