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Engineering the 30-Meter Telescope

Posted by kdawson on from the yet-another-football-field dept.

yyzmcleod writes "When completed in 2018, the Thirty Meter Telescope (TMT) will be the world's largest and most powerful, with a resolving power 100 times that of Hubble. As TMT's preliminary design review nears, this article details how its enclosure, segmented mirror and adaptive optics will work to let astronomers peer back to the beginning of the Cosmos."

64 comments

  1. If only they had a 30 foot server... by ravenspear · · Score: 1, Funny

    then maybe I could actually read the article. ;)

    1. Re:If only they had a 30 foot server... by The+Leather+Duke · · Score: 2, Informative

      Do not despair, the article is here.

  2. Thirty Meter Nano-Telescope by Shard013 · · Score: 3, Funny

    I was hoping for the Thirty Meter Nano-Telescope (TMNT)

    1. Re:Thirty Meter Nano-Telescope by GordonCopestake · · Score: 3, Funny

      Kowabunga dude!

  3. good forethought with that acronym. by Anonymous Coward · · Score: 0

    The 20 meter telescope can just go fuck itself, huh? Why not call it the 30mT?

    1. Re:good forethought with that acronym. by mangu · · Score: 1

      Why not call it the 30mT?

      Yes, calling it the "thirty millitesla" would avoid a lot of confusion...

  4. Correct link by afaik_ianal · · Score: 3, Informative

    Correct link without the 501 error: http://www.canadianmanufacturing.com/designengineering/features/industryfocus/article.jsp?content=20090512_125904_8252

    1. Re:Correct link by Tablizer · · Score: 1

      Correct link without the 501 error:

      I don't want to hear about your wardrobe malfunctions.
           

      --
      Table-ized A.I.
  5. World's largest? Not quite... by Dusty101 · · Score: 5, Informative

    "World's largest and most powerful".

    Yeah, except for the 42-m E-ELT, also slated for 2018-ish. And that's still excluding radio telescopes...

    1. Re:World's largest? Not quite... by timeOday · · Score: 1

      How can you directly compare radio telescopes when they aren't even working in the visible spectrum? For that matter, does this new telesope really have 10x the resolution of Hubble - in the same frequencies? I know very little about astronomy, but often when you hear the newest telescope is X times better than the old one, it turns out it isn't even measuring the same thing, or it has better sensitivity but less resolution, or some sort of apples-to-oranges tradeoff.

  6. Thirty Meter Telescope will go a long ways! by Celeste+R · · Score: 2, Interesting

    This telescope design has a lot of promise.

    My father is an optical designer/astronomer, and I grew up around many different designs that actually do work.

    Why is a long telescope important? Well, once you eliminate the tube sag, it has certain properties.

    This design almost eliminates ambient light (think of looking at the moon through fog compared to looking at the moon on a clear night in the mountains).

    Because of this, even "tiny" 6-inch long-tube designs can match or exceed 24" or better telescopes in detail and quality. The design is out of fashion with the general public mostly because of portability and ease of use.

    The design of this telescope in specific almost TRIPLES the effective length of the telescope, making the ambient light-reducing qualities much more enhanced.

    Something like this would be able to look at ultra-distant objects with excellent image quality, putting spy satellite image quality to shame.

    I have one caveat with this design though, I'm not very fond of the Cassegrain system because the quality of the optics is often sacrificed in the process of creating them.

    --
    There are no perfect answers, only the right questions. More questions at http://foresightandhindsight.blogspot.com/
    1. Re:Thirty Meter Telescope will go a long ways! by digitalchinky · · Score: 1

      I have one caveat with this design though, I'm not very fond of the Cassegrain system because the quality of the optics is often sacrificed in the process of creating them.

      I'm pretty much exclusively involved in the radio parts of the spectrum, not entirely dissimilar, though in this particular case the system is so large and sensitive I'm not sure that it would lend itself very well to any other designs - please do call me out if I'm wrong here though, happy to change my outlook. The alternative to the Cassegrain design would mean the detection equipment has to be located wherever the focal point of the dish happens to fall, somewhere up front of the mirror. My assumption is that this stuff is super sensitive to vibration and the environment, so probably when it comes to a dish this size, it's probably just easier to engineer this way, the losses wouldn't be so large that it'd matter that much :-)

      Now to point this sucker at the sun and fry some ants.

    2. Re:Thirty Meter Telescope will go a long ways! by Anonymous Coward · · Score: 5, Insightful

      1 'tube sag' only applies to telescopes which HAVE a long tube, that is, long focal-length refracting telescopes which have a lens at the front end, not reflectors, which have a mirror at the back end.

      2 almost all large telescopes do not use any sort of 'tube' at all for supporting the optics, any solid tube would be too heavy to be useable, they use open-frame supports

      3 'detail'....if by this you mean 'angular resolution' then no, a 6" telescope can NEVER beat a 24" one, the angular resolution [THETA] is determined by the equation sin THETA = 1.22 X [wavelength of light] / [telescope diameter], so a 24" scope will *always* have 4 times better (ie smaller) angular resolution than a 6" does.

      4 even with this taken into consideration, large observatory-class telescopes are made large for their light-gathering capabilities, which allow them to see extremely faint objects, -not- for their angular resolution, which is limited not by the telescope design but by atmospheric seeing conditions, these fall far below the theoretical limit of a large telescope.

      5. The 30m scope is not a Cassegrain, it's a Ritchey-Chretiene, same design as used in many other large and very successful observatories, and trust me, the people who build observatory-grade optics are very able to construct ANY shape of mirror they are asked to without mucking it up. Perhaps you're thinking of -amateur- telescope makers having a go at grinding a Schmidt-Cassegrain corrector plate in their garage/shed/back room using a grinding-rig they made out of broom-handles and a washing machine motor?

      Your father may well be an optical designer and astronomer, you're not though.

      Not trying to be nasty, it's just that nearly everything you wrote is either wrong, misleading, or half-right but mis-applied, and to the wrong thing.

    3. Re:Thirty Meter Telescope will go a long ways! by Tomfrh · · Score: 1

      Because of this, even "tiny" 6-inch long-tube designs can match or exceed 24" or better telescopes in detail and quality.

      I've owned a few telescopes and this statement sounds a little far fetched to me.

    4. Re:Thirty Meter Telescope will go a long ways! by Physics+Dude · · Score: 2, Informative

      "a 6" telescope can NEVER beat a 24" one"

      It sounds like you don't have much practical experience using telescopes either. ;)

      The Rayleigh equation you state is for the theoretical *MINIMUM* resolvable angle based on aperture size but if you think that's all there is to telescope optics, you probably haven't had experience using a wide range of telescopes. I've used home-ground 10" refractors that have MUCH better resolving power than other commercial 14" scopes.

      Size matters, but so do a lot of other factors that ultimately determine a scope's actual resolving power.

    5. Re:Thirty Meter Telescope will go a long ways! by Audiophyle · · Score: 1

      Just a quick note even though you're an AC, a Ritchey-Chretien optical system is a Cassegrain design, so your criticism here is wrong. The TMT is actually an aplanatic variation of the RC design.

      FWIW, some of the best mirrors on the consumer market are handmade, but obviously the TMT is far from being this type of mirror.

    6. Re:Thirty Meter Telescope will go a long ways! by Anonymous Coward · · Score: 0

      ok, a 6 and a 24 of comparable optical quality, eg both 1/10th wave, and with all other factors equalised.....I didn't want to be too long winded on the original reply, plus I forgot it was /. and very foolishly assumed that no-one would be dumb enough to think I meant a top-notch 6" apo versus a P.o.S. 24" reflector that's barely 1/4 wave, just to score a few moron, sorry, pedant points off me.. happy yet?

      ps 5" SCT, 8" SCT, 3.5" Mak-Cass, 4.5" newtonian bino-scope, 80mm apo triplet, 32" newtonian, and a few others I've sold on since then..........

      pps batchelors in astrophysics, PhD in rocket science, you're not the only "Physics Dude" here.

    7. Re:Thirty Meter Telescope will go a long ways! by Anonymous Coward · · Score: 0

      True, and you are correct, I left out 'classic' before 'Cassegrain', was just pointing out that RC's are one of the more common designs for large telescopes and in general have not been found to suffer from optical fabrication difficulties .

      I agree on the hand-made small mirrors being some of the best too, there's a very nice story out there in interwebs land about a 10-yr old in the states who hand-ground a 1/80th-wave (!!!) 6" mirror on his first attempt..........

    8. Re:Thirty Meter Telescope will go a long ways! by Celeste+R · · Score: 1

      In the spirit of a friendly discussion, I'll reply.

      Common optical designs typically suffer from optical coma (where rays of light end up in unintended places). This 30-meter telescope is designed to eliminate that, however typical classical Cassegrains do suffer from this.

      Secondly, there's the issue of spherical aberration, where light near the edges of the optics becomes blurred. This is preventable by design as well.

      There is yet another issue of optical -quality-, which is purely dependent on the manufacturing process and type of glass used. Even the "best" optics available in non-military markets suffer from minute cracks in the glass surface. This is preventable mostly by perfecting the manufacturing process itself, but is also dependent on having a good design.

      Developing perfect optics is very difficult beyond sizes of 8 inches. It's simply beyond the technical know-how of most mirror fabrication facilities to even make a flat mirror that is perfect, yet alone a mirror that isn't flat.

      My original comment stated that a long tube design reduces ambient light. Even the very large telescopes suffer from this, and that itself is the primary reason why locations that are "light pollution" free are highly sought after. However, not many very large telescopes are designed to remedy this problem, but are rather designed to magnify beyond it.

      Having too much faith in optics that are poorly made will only get you so far, and designs that cannot be accurate within one wavelength (of light) can't magnify to their heart's content. (disclaimer, I don't know how well these optics are made.)

      Not trying to be nasty, it's just that nearly everything you wrote is either wrong, misleading, or half-right but mis-applied, and to the wrong thing.

      I do not see how I am misleading anyone, or misapplying what I just stated. Your post may be half flamebait, but people can always know more about astronomy.

      --
      There are no perfect answers, only the right questions. More questions at http://foresightandhindsight.blogspot.com/
    9. Re:Thirty Meter Telescope will go a long ways! by RespekMyAthorati · · Score: 1

      I have a noob question:

      Is there any theoretical upper limit on the resolving power of a reflecting telescope? For example, would a kilometer mirror necessarily be better than a 100-meter mirror? Would a 100-kilometer mirror necessarily be better than a 10-kilometer mirror?

      I was imagining an army of robots spreading out across the solar system, turning asteroids into telescopes. Over centuries these robots could create hundreds of thousands of reflecting telescopes whose images could be combined to produce higher and higher resolution pictures, perhaps imaging exoplanets as if they were in our solar system.

      Is there any theoretical reason why this wouldn't work?

    10. Re:Thirty Meter Telescope will go a long ways! by Celeste+R · · Score: 1

      Is there any theoretical upper limit on the resolving power of a reflecting telescope? For example, would a kilometer mirror necessarily be better than a 100-meter mirror? Would a 100-kilometer mirror necessarily be better than a 10-kilometer mirror?

      Telescopes have no theoretical upper limit in design, however in practice it's very different.

      The wavelength of visible light is between 0.7um and 0.4um. A mirror that is made to have no less than that much surface irregularity is very difficult to make, but it can be done.

      The larger a mirror is, the more surface area you have to manufacture. A single flaw or error in manufacture could render an entire mirror either useless or of inferior quality.

      I'm also absolutely sure that there is a limit to how much you'd want a mirror to be made due to temperature expansion/contraction. Temperature can be controlled, but that requires an accurate cooling system.

      Telescope making is an art, and even the telescope-maker giants have a very difficult time trying to push the limits (innovation in those places is another topic entirely).

      --
      There are no perfect answers, only the right questions. More questions at http://foresightandhindsight.blogspot.com/
  7. oh man.... by R.Morton · · Score: 3, Funny

    2018 !, I wanted to use the 30 meter telescope to fry ants in other galaxies now !, or maybe see some boobs.

    R.Morton

    --
    modded quote "what's that he's talking about? Windows , Never had a problem with Windows till I tried to use it."
    1. Re:oh man.... by Anonymous Coward · · Score: 0

      Maybe fry boobs in other galaxies?

    2. Re:oh man.... by Muad'Dave · · Score: 1

      Hold your horses, Veruca. Daddy will get you one when we're done with this crazy tour.

      http://en.wikipedia.org/wiki/Veruca_Salt#Veruca_in_the_1971_film

      --
      Tiller's Rule: Never use a word in written form that you've only heard and never read. You will end up looking foolish.
    3. Re:oh man.... by R.Morton · · Score: 1

      Yeah, Willy Wonka rocks, have not seen that in years, I really hated that KID she was so damned spoiled reminds me of my sisters kids.

      R.Morton

      --
      modded quote "what's that he's talking about? Windows , Never had a problem with Windows till I tried to use it."
  8. I've Seen It by DynaSoar · · Score: 2, Funny

    "...to let astronomers peer back to the beginning of the Cosmos."

    I remember that. It had music by Vangelis and a Seyfert galaxy in the forward view screen.

    --
    "I may be synthetic, but I'm not stupid." -- Bishop 341-B
  9. Collecting area versus resolution by Trapezium+Artist · · Score: 5, Informative
    The summary erroneously suggests that the TMT will have "resolving power 100 times that of Hubble": this is incorrect.

    As the actual article notes on its first page, TMT will have roughly 100 times the collecting area of Hubble: this goes as the square of the diameter of the telescope, so with TMT = 30m and Hubble = 2.5m, that's about right.

    Resolving power (if the TMT can be made diffraction-limited, which it is aiming to do, but which is hard nevertheless) gets better linearly with the diameter, so TMT will have roughly 10 times the resolving power of Hubble.

    The more appropriate space-based comparison in 2018 will be JWST which has a diameter of 6.5m, although JWST and ground-based ELTs are more properly thought of as being complementary, not competitive: they do different things.

    But as already noted, the more appropriate comparison is with the European E-ELT which is under Phase B study now and is baselined for 42m diameter.

    More interesting is where the TMT and E-ELT will be located: same hemisphere or not? Current bets are on E-ELT being in Chile, with TMT possibly going to Mauna Kea. This would be a better outcome for us astronomers than having both in the south, IMHO.

    1. Re:Collecting area versus resolution by DerekLyons · · Score: 1

      In addition, no earthbound scope can 'see' into the UV and IR bands as the atmosphere absorbs them.

  10. If ground-based telescopes are so good by Joce640k · · Score: 1

    Then why are we fixing the Hubble telescope (and developing newer space telescopes...)

    Seems to me like the era of expensive/hard to maintain space telescopes is over.

    --
    No sig today...
    1. Re:If ground-based telescopes are so good by Anonymous Coward · · Score: 0

      Ground based telescopes will always be worse than space based telescope due to the atmosphere.

      The only place ground based telescopes beat space based telescopes is ease of access.

      Now...a lunar base with a massive telescope...that wouldn't be all that bad.

    2. Re:If ground-based telescopes are so good by Trapezium+Artist · · Score: 4, Informative

      As I said, ground- and space-based telescopes are actually highly complementary: it sounds greedy, but we really need both.

      Space has the advantage of there being no atmosphere to block some of the incoming light and blur the image. Also, if you cool your telescope down (e.g. ESA's Herschel being launched tomorrow and NASA/ESA/CSA JWST in 2014), then you benefit from greatly reduced sky background at infrared wavelengths. This can result in an enormous increase in sensitivity in situations where the background matters, e.g. imaging of extremely faint sources.

      Also, space-based telescopes can cover a wider wavelength range, including wavelengths that don't make it through the atmosphere, so some kinds of thing must be done from space (e.g. X-ray astronomy as in NASA's Chandra and ESA's XMM-Newton).

      At the same time, space telescopes are much smaller than state-of-the-art ground-based ones, and thus the ground-based telescopes can catch many more photons over all. For some science (e.g. medium- to high-resolution spectroscopy of extremely faint objects where the background doesn't matter), it's all about the number of photons you can collect.

      Also, if you can implement adaptive optics on your ground-based telescope, you can get higher resolution than in space.

      As an example of true synergy, look at the many studies done jointly by HST and the ground-based 8-10m telescopes like the VLT, Keck, Gemini, and so on. In many cases, both were needed to complete the study.

      Indeed, there are many of us helping develop both JWST and ground-based ELTs like E-ELT and TMT for exactly the same reason: we need both to get a more complete picture of what's going on out there.

    3. Re:If ground-based telescopes are so good by Shag · · Score: 1

      Ground based telescopes will always be worse than space based telescope due to the atmosphere.

      Ground based telescopes will always have to deal with the atmosphere, and space based ones won't, yes. That's rarely the only factor in the results.

      The only place ground based telescopes beat space based telescopes is ease of access.

      Ah, but ease of access translates to ease of upgrades. Hubble's infrared imaging capability is about to be upgraded from 256x256 to 1024x1024... meanwhile, folks in Hawai have been at 4096x4096 for six years already, since they developed the chips for the next (James Webb) space telescope's infrared camera.

      Now...a lunar base with a massive telescope...that wouldn't be all that bad.

      Sure, as long as you can fabricate instruments from regolith in lunar gravity. Otherwise, you're shipping stuff from Earth to the Moon, which is even more expensive than putting it into orbit.

      --
      Village idiot in some extremely smart villages.
    4. Re:If ground-based telescopes are so good by Trapezium+Artist · · Score: 1

      Ah, but ease of access translates to ease of upgrades. Hubble's infrared imaging capability is about to be upgraded from 256x256 to 1024x1024... meanwhile, folks in Hawai have been at 4096x4096 for six years already, since they developed the chips for the next (James Webb) space telescope's infrared camera.

      It's slightly more complicated than that. JWST's near-IR detectors were manufactured by Teledyne (formerly Rockwell), with the University of Hawai'i involved under contract for development and testing. Specs were set at the project level and the detectors have also been tested under contract by the STScI Detector Lab and, of course, by the instrument teams using them (Univ Arizona for NIRCam, GSFC/ESA for NIRSpec, GSFC/CSA for FGS/TFI).

      What Hawai'i have always been very good at is giving the impression that they develop detectors themselves :`)

      While they're also good at getting them on the telescope quickly, it's often on small telescopes like the UH 88 inch in lashed-up dewars and (to be honest) not delivering much science.

      4096x4096 pixel infrared mosaics are also now available on bigger telescopes such as the UKIRT 3.8m (WFCAM), CFHT 3.6m (WIRCAM) and the VLT 8.2m (HAWK-I). An even larger 8192x8192 pixel mosaic is currently under commissioning at VISTA. These are the current state-of-the-art, with bigger arrays coming for the ELTs.

      (Not trying to rain on the Hawai'ians' parade particularly [some of my best friends are ... etc.], just trying to set the record straight.)

    5. Re:If ground-based telescopes are so good by Trapezium+Artist · · Score: 1

      Good job I put that bit in about "some of my best friends are Hawai'ans", eh, Dan, now that I've seen that you're a TO for the 88 inch ... :`)

      After all, it would hypocritical for me not to remember that through my Hawai'in friends (a fellow Englishman building IR instrumentation at the IfA, shall we say), I made good use of one of Klaus Hodapp's earlier "lashed-up" cameras on the 88 inch, the one with the first 256x256 NICMOS3 array in. This happened as part of the deal that was made when Hawai'i lost its bid for an HST IR instrument (HIMS) to Arizona's NICMOS: some of the Hawai'i folk got on the NICMOS science team and some of the detectors were tested in Hawai'i.

      Since I was actually working in Arizona on the NICMOS instrument for HST at the time, this was a slightly curious happening, since Arizona themselves didn't even have such an array on the air at that point (1990-ish).

      Astro-politics: you've got to love it.

    6. Re:If ground-based telescopes are so good by Shag · · Score: 1

      JWST's near-IR detectors were manufactured by Teledyne (formerly Rockwell), with the University of Hawai'i involved under contract for development and testing.

      What Hawai'i have always been very good at is giving the impression that they develop detectors themselves :`)

      Depends on whether your definition of "develop" involves fabrication, I guess. You just said right up there that Rockwell manufactured them and UH was involved for development and testing. I think MIT Lincoln Labs was in the mix too, but at that point in time I was wrangling an SCO OpenSewer box at a trucking company, and I don't really want to go ask Don Hall even if he's in the same building, so I'll take your word for it. :)

      While they're also good at getting them on the telescope quickly, it's often on small telescopes like the UH 88 inch in lashed-up dewars and (to be honest) not delivering much science.

      Darn right! A slightly-smaller-than-Hubble scope that doesn't have 5-7 nights of proposals for every available night like larger scopes do can actually be useful for testing stuff. But prototype chips aren't really what you want to use for science - the raw images look like crap, the chips tend to "explosively delaminate" (one of ULBCAM's did last year) and about all you can do is send grad students tilting at windmills trying to develop data reduction routines, mwahaha.

      2000-2004 was a good period for UH88 getting next-gen instruments - OPTIC, ULBCAM, SNIFS. But Pan-STARRS has been a mere 2 years away for the last 3 years, and may be a mere 2 years away for real this time, so those may be the last major new things 88 sees.

      4096x4096 pixel infrared mosaics are also now available on bigger telescopes such as the UKIRT 3.8m (WFCAM), CFHT 3.6m (WIRCAM) and the VLT 8.2m (HAWK-I).

      ...using, at least in the case of WFCAM, the production versions of those same Rockwell chips. I've actually had a couple nights on UKIRT with WFCAM for UKIDSS, it's a nice setup.

      Good job I put that bit in about "some of my best friends are Hawai'ans", eh, Dan, now that I've seen that you're a TO for the 88 inch ... :`)

      Among other things... for the remainder of this week. Drop me an email and I can say a lot more.

      --
      Village idiot in some extremely smart villages.
  11. I'm trying to think by MichaelSmith · · Score: 1

    I remember that. It had music by Vangelis and a Seyfert galaxy in the forward view screen.

    Thought back through my collection and checked the wiki. Drew a blank. So which movie are you thinking of?

    --
    http://michaelsmith.id.au
    1. Re:I'm trying to think by Muad'Dave · · Score: 2, Informative

      The Cosmos TV series by Carl Sagan. I loved that show.

      --
      Tiller's Rule: Never use a word in written form that you've only heard and never read. You will end up looking foolish.
    2. Re:I'm trying to think by Sponge+Bath · · Score: 1

      I bought the Cosmos DVDs to watch and caught something I missed the first time. They used a short clip of Pink Floyd's One of These Days (I'm Going to Tear You into Little Pieces) as background audio in one episode. Good ol' Puff Daddy Sagan.

    3. Re:I'm trying to think by Muad'Dave · · Score: 1

      The Cosmos DVDs were remastered to include updated special effects and some previously unaired footage. They might've updated the soundtrack, but the Floyd was probably in the original.

      If by 'Puff Daddy' you mean major toker, than you're correct - he used marijuana 'avidly'.

      --
      Tiller's Rule: Never use a word in written form that you've only heard and never read. You will end up looking foolish.
    4. Re:I'm trying to think by StikyPad · · Score: 1

      I tried watching it recently, but between the horrible effects, dated information, bizarre analogies, odd filming locations, ridiculous "spaceship" set, and his permagrin, I just couldn't take it seriously at all. I'm sure it fit right in to contemporary 1980, but IMO it's not quite a "timeless" documentary. It was more valuable to me as a view into the late 70s/early 80s than general astronomy. Obviously that wasn't the goal of the series, which just made it all the more cringe-worthy.

      --
      https://www.eff.org/https-everywhere
    5. Re:I'm trying to think by Muad'Dave · · Score: 1

      Remember, he was probably baked beyond Alaska while writing/filming.

      --
      Tiller's Rule: Never use a word in written form that you've only heard and never read. You will end up looking foolish.
  12. Yeah, but where? by niktemadur · · Score: 1

    Reading TFA is further evidence that these so-called journalists always neglect some basic piece of information that's right in front of their nose.

    - "Hey Kent, I proof-read your piece on the telescope, you forgot to indicate where in the world it's gonna be installed".
    - "Sorry about that, I'll get right on it, Mr White".

    So what is it, Chile? Hawaii? Canary Islands? El Segundo, California?

    --
    Lil' Thindime, lilting a lacrimose lament, krashes the kwaint konfines of Kokonino Kounty
    1. Re:Yeah, but where? by Shag · · Score: 2, Interesting

      They've narrowed it down to two sites. It's either going on Mauna Kea, or in Chile.

      I was just talking to a guy today who works at an 8-meter-class telescope on Mauna Kea, and he was saying that right now, they have proposals for 7 times as many nights as there actually are available. He thought this might drop off a bit once the TMT is built, but I figure hey, the TMT is only one scope, so at most one of those 7 can go use it. The 8-10 meter guys are safe for probably a good while - Keck I is 17 years old this year, and the 30-year-old, 3.6-meter Canada-France-Hawaii telescope is still relevant and doing good work.

      Ten years from now, maybe we have a couple 30-40 meter telescopes, but a huge amount of the serious work will still be getting done on stuff 10 meters or smaller.

      --
      Village idiot in some extremely smart villages.
    2. Re:Yeah, but where? by confused+one · · Score: 1

      They haven't decided yet. Either Mauna Kea, Hawaii or Atacama Desert, Chile.

    3. Re:Yeah, but where? by niktemadur · · Score: 2, Interesting

      They've narrowed it down to two sites. It's either going on Mauna Kea, or in Chile.

      and

      They haven't decided yet. Either Mauna Kea, Hawaii or Atacama Desert, Chile.

      Thanks, guys. The article did not make it apparent, although many big astronomy projects nowadays end up at either site.

      It's been a while since I've read about Arizona bagging a major project such as this, same with the Canary Islands. South Africa is sometimes floated around in these articles.
      A possibility in my neck of the woods is the San Pedro Mountain Range in Baja California. To make the pitch more plausible, the local state government has begun installing low-glare street lighting in nearby urban areas. The Mexico City based UNAM Astronomy Institute paved 120 kms of road a couple of years ago, from sea level all the way up to the astronomical village.

      So you never know where these things could end up.

      --
      Lil' Thindime, lilting a lacrimose lament, krashes the kwaint konfines of Kokonino Kounty
    4. Re:Yeah, but where? by Anonymous Coward · · Score: 0

      the TMT is only one scope, so at most one of those 7 can go use it.

      What kind of math is that? The 30-meter telescope has (30/8)^2 = 14 times the light gathering power as your guy's telescope, so you can fit 14x as many people in one night and they'll all get strictly better quality images than they would have on one night on a 8-meter telescope because of the extra angular resolution.

    5. Re:Yeah, but where? by Shag · · Score: 1

      Heh... interesting way of looking at it.

      "Sorry, Dr. Tully, but you only get 45 minutes." :)

      I wonder whether they'd actually do that.

      --
      Village idiot in some extremely smart villages.
    6. Re:Yeah, but where? by Anonymous Coward · · Score: 0

      What's to wonder? Researchers give a list of target coordinates, exposure times, and optional filters ahead of time. The telescope operator collects a bunch of those, solves the traveling salesman problem in order to minimize telescope movement, and runs the sequence of operation.

      What, you thought that Dr. Tully flew to Hawaii and was left alone with the telescope for 45 minutes?

  13. 42 meters? by sznupi · · Score: 4, Funny

    Something gives me the feeling E-ELT will give us the ultimate answer about our universe.

    --
    One that hath name thou can not otter
    1. Re:42 meters? by StikyPad · · Score: 1

      Too bad the world ends in 2012 :/

      --
      https://www.eff.org/https-everywhere
  14. What a bizarre troll post! by Anonymous Coward · · Score: 0

    I'm still trying to decide whether you're utterly clueless about optical and telescope design and construction - basically every freakish word you wrote is completely wrong on so many levels - or if you're knowingly posting complete nonsense just to give guys like me something to puzzle over.

  15. Slashdotted? by garphik · · Score: 1

    Is the website accessible ?

  16. in before... by ilblissli · · Score: 0

    in before "i can see my house from here" comments.

  17. Not all facts are equal... by Anonymous Coward · · Score: 0

    I was confused by the opening paragraph and the need to check the facts before making statements, however warm and fuzzy they seem.

    The author gets it wrong as soon as it begins:

    "When Scottish mathematician James Gregory first peered into the heavens using his revolutionary reflecting telescope, little could he have known that, 340 years later, his scientific descendants would begin work on The Thirty Meter Telescope (TMT), ...."

    As far as I have been able to determine, James Gregory did design such a telescope, but was not adroit enough a technician to actually build a working model. Hooke built the first working model of the 'Gregorian' telescope in 1673 (or 74), only two years prior to Gregory's death.It
    is therefore, most unlikely that Gregory ever got to actually 'peer into the heavens using his revolutionary reflecting telescope".

    It does create a touching image, even though it is very possibly not in accordance with reality...

  18. Scratch the above... by sznupi · · Score: 1

    ...thinking about this a bit more seriously, it might actually, and...more appropriately (? ;p ), give us THE QUESTION! :>

    (taking into account how especially, among others, in astronomy/astrophysics new observations and answers often lead to more profound dillemas)

    --
    One that hath name thou can not otter
  19. And Atmospheric Blur by Tablizer · · Score: 1

    so TMT will have roughly 10 times the resolving power of Hubble.

    That excludes the blur caused by the atmosphere, which Hubble does not have to worry about. TMT will have "adaptive optics" to partially compensate for atmospheric blur, but it is still a relatively new and evolving technique with certain limits. A direct comparison with Hubble depends on lots of factors and technical issues.
                 

    --
    Table-ized A.I.
    1. Re:And Atmospheric Blur by RalphTheWonderLlama · · Score: 1

      Yeah, exciting stuff, but Ed Weiler himself just said at the recent Atlantis post launch news conference something to the effect that he always hears about new telescopes that will be xx times better than Hubble, but you have to take those with a huge grain of salt coming from land based telescopes. There is a lot of buzz about adaptive optics but not much substance yet and you can't see UV light from the ground.

      agreed to an equal partnership to build the worldâ(TM)s largest telescope

      What about that huge radio telescope in Puerto Rico or South America or wherever the hell it is that's built into a mountain? I guess they mean optical?

      --
      simple, fast homepage with your links: http://www.ngumbi.com/
    2. Re:And Atmospheric Blur by Trapezium+Artist · · Score: 1

      Well, Ed would say that, wouldn't he? :`)

      Adaptive optics is not quite the same as raw diffraction-limited imaging, no, but it's getting pretty damn good. It's a lot more than buzz: all major telescopes use it routinely.

      I've been using for many years already from ground-based 8-m telescopes and it really does deliver more than HST can ... in the near-IR. Nope, it can't compete at optical wavelengths with HST ...

      You're thinking Arecibo: Puerto Rico and yes, it's radio.

  20. Seeing and Rayleigh Criterion by irchans · · Score: 1

    'detail'....if by this you mean 'angular resolution' then no, a 6" telescope can NEVER beat a 24" one, the angular resolution [THETA] is determined by the equation sin THETA = 1.22 X [wavelength of light] / [telescope diameter], so a 24" scope will *always* have 4 times better (ie smaller) angular resolution than a 6" does.

    If I look through a 6" telescope on a typical evening here in Pennsylvania, I will have a resolution of about 2 arcseconds.

    If I look through a 24" telescope on a typical evening here in Pennsylvania, I will have a resolution of about 2 arcseconds.

    The limiting factor is Astronomical Seeing not the Rayleigh criterion which you stated quite correctly.

    1. Re:Seeing and Rayleigh Criterion by Anonymous Coward · · Score: 0

      "4 even with this taken into consideration, large observatory-class telescopes are made large for their light-gathering capabilities, which allow them to see extremely faint objects, -not- for their angular resolution, which is limited not by the telescope design but by atmospheric seeing conditions, these fall far below the theoretical limit of a large telescope."

      RTFP.