Slashdot is powered by your submissions, so send in your scoop

 


Forgot your password?
Close
typodupeerror
×
Space

Ask Chris McKinstry About Giant Telescopes, Etc. 138

Posted by timothy from the it's-a-long-long-way dept.
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.
This discussion has been archived. No new comments can be posted.

Ask Chris McKinstry About Giant Telescopes Etc. More

Ask Chris McKinstry About Giant Telescopes Etc.

Comments Filter:
  • you know what they say about the size of a man's telescope... nudge-nudge, wink-wink...

    ----

  • might as well ask it now.. (Score:5)

    by Blue Lang ( 13117 ) on Wednesday June 28, 2000 @06:10AM (#971007) Homepage
    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?

  • Terrestrial Optical Telescopes (Score:5)

    by pb ( 1020 ) on Wednesday June 28, 2000 @06:11AM (#971008)
    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?
    ---
    pb Reply or e-mail; don't vaguely moderate [ncsu.edu].
  • Why would we interview Christie Brinkley about telescopes???!!?!

  • BHT (Big Honkin' Telescopes) (Score:3)

    by Golias ( 176380 ) on Wednesday June 28, 2000 @06:14AM (#971010)
    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?

  • funding (Score:5)

    by jmayes ( 176640 ) on Wednesday June 28, 2000 @06:15AM (#971011)

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

  • 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?

    :)

  • Why single-mirror? (Score:5)

    by jd ( 1658 ) <imipak&yahoo,com> on Wednesday June 28, 2000 @06:18AM (#971013) Homepage Journal
    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?)

  • 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.

  • vs HST (Score:1)

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

  • 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 ;)

  • 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.

  • 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.
  • I think the BFT-9000 is next...
  • 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?

  • Re:Why on the ground (Score:3)

    by lennon ( 200343 ) on Wednesday June 28, 2000 @06:27AM (#971021)
    It is cheaper to control light pollution than build something in space. http://www.darksky.org [darksky.org] is just one of the places where a little money go a long way to fight light pollution.

  • Atmospheric Turbulence Correction? (Score:3)

    by exploder ( 196936 ) on Wednesday June 28, 2000 @06:28AM (#971022) Homepage
    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?

  • 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

  • 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.
  • I guess you never really played streetfighter...

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

  • 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.

  • Yeah, they're big... (Score:5)

    by viper21 ( 16860 ) <scott@@@iqfoundry...com> on Wednesday June 28, 2000 @06:32AM (#971027) Homepage
    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
  • 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.

  • CCD or what? (Score:4)

    by paRcat ( 50146 ) on Wednesday June 28, 2000 @06:32AM (#971029)
    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?

  • 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
    --

  • Moon closeup (Score:3)

    by russiste ( 180524 ) on Wednesday June 28, 2000 @06:33AM (#971031) Homepage
    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 [homestead.com]... or maybe confirm them. ;-)

    Greg
  • 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?
  • 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?

  • Technology (Score:3)

    by rw2 ( 17419 ) on Wednesday June 28, 2000 @06:35AM (#971034) Homepage
    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?

  • Distributed Computing Problems (Score:3)

    by Aravaipa ( 30801 ) on Wednesday June 28, 2000 @06:35AM (#971035)
    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?

  • How can we help? (Score:5)

    by Mignon ( 34109 ) <satan@programmer.net> on Wednesday June 28, 2000 @06:36AM (#971036)
    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.

  • SXLHBMFT.

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

    (I'm not an astronomer.)
  • Thats just horrible, really horrible...

  • Re:Terrestrial Optical Telescopes (Score:3)

    by chgreer ( 113314 ) on Wednesday June 28, 2000 @06:41AM (#971039)
    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 [noao.edu] 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.
  • Just for the record, when the Paramal Observatory is finished as planned, it will have 4 large telescopes running in an optical array.


    ...phil
  • 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.

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

    --
  • +1:Very Good Point!

    I wish more people would understand that concept.

  • How do you guys do it? (Score:4)

    by pc486 ( 86611 ) on Wednesday June 28, 2000 @06:48AM (#971045) Homepage
    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.
  • Will the next project after OWL be named BFT?

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


    --

  • 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?

  • 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?


  • 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
  • Igor Aleksander [ic.ac.uk] 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

  • The big at the expense of the small (Score:2)

    by Anonymous Coward
    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

  • Adaptive Optics and Inferometers (Score:3)

    by wazzzup ( 172351 ) <astromac@nOsPaM.fastmail.fm> on Wednesday June 28, 2000 @07:08AM (#971052)
    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?
  • 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.
  • 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?<p>
  • 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
  • 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 ...

  • 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...

  • Re:Why single-mirror? (Score:5)

    by pq ( 42856 ) <rfc2324&yahoo,com> on Wednesday June 28, 2000 @07:56AM (#971058) Homepage
    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.
  • 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?

  • F***! It posted under my name, but stripped the HTML formatting. I don't get it - what's up with /. today?
    Anyone?
    Anyone?
    Ferris?

  • 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
  • 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?

  • (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?

  • 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 [gtc.ia.es], the LBT [arizona.edu], the SALT [saao.ac.za], the VISTA [qmw.ac.uk], the LAMOST [bao.ac.cn], the DMT [dmtelescope.org], the CELT [ucolick.org], the XLT [astro.lu.se], the OWL [eso.org], 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 [clearskyinstitute.com] the bettest scope is in space.
    --
    BeDevId 15453 - Download BeOS R5 Lite [be.com] free!
  • 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 [ncsu.edu].

  • GAC (Score:4)

    by Dungeon Dweller ( 134014 ) on Wednesday June 28, 2000 @08:13AM (#971067)
    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.
  • 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 [harvard.edu]?

    Hooptie

  • 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 [hawaii.edu] 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 [hawaii.edu] for NASA's Origin's program.)

    Louis Wu

    Thinking is one of hardest types of work.

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

  • 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.
  • 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
  • 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 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 [nasa.gov] telescope consists of 36 smaller mirrors (supplied by Kodak [kodak.com]). 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 [uci.edu]).

    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.
  • 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?
  • 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.

  • 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?
  • 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?

  • 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.
  • 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.
  • 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)?

  • 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.
  • 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.

  • 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!
  • In developing an artificial intelligence (see the "hacking conciousness" link [mindpixel.com] 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
    ---

  • 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.

  • 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 [ncsu.edu].
  • 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 [egroups.com] archives and from Jeff Elman's Finding Structure in Time [ucsd.edu]. 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.
  • 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.

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

    Too much light coming from such a nearby object.
  • 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.

  • 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.

    --
  • 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.

  • 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

  • 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?

  • Do you get sick of hearing Uranus jokes?

  • 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.com]:

    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.

  • 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?
    __
  • 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?

  • 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.

  • 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.

Slashdot Top Deals

If you have a procedure with 10 parameters, you probably missed some.

Close