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World's Largest Telescope Up and Running

apdyck writes "ITWire is reporting that the world's largest telescope is now up and running, conducting one-year series of tests. The Great Canary Telescope, located in the Canary Islands, is the largest telescope in the world at 10.4 m (34') in diameter. Not for your average stargazer! 'The reflective telescope, sometimes also called GranTeCan, uses technology called adaptive optics, in which the mirror changes its shape in order to correct distortions of light caused by the Earth's atmosphere. The telescope is part of the Observatorio del Roque de los Muchachos, located on the island of La Palma, Spain, within the Atlantic Ocean.'"

120 comments

  1. Worlds Largest Telescope Up and Running by ajenteks · · Score: 4, Funny

    Nothing for you to see here. Please move along. Damn :(
    1. Re:Worlds Largest Telescope Up and Running by Anonymous Coward · · Score: 0

      That's what he said... followed by that's what she said.

  2. Who you gonna call? by imstanny · · Score: 3, Funny

    The telescope is located on top of a volcanic peak that is 2,400 meters (about 1.5 miles) above sea level.

    Someone call Pierce Brosnan. Tell him to bring NASA's experimental locator beacon.

    1. Re:Who you gonna call? by Anonymous Coward · · Score: 0

      What are they going to do when half of the island falls into the sea and creates 1000 ft high tsunami waves. Great location for something so expensive.

  3. Hey by Anonymous Coward · · Score: 4, Funny

    It's not the size that matters. It's how you use it.

    1. Re:Hey by Anonymous Coward · · Score: 0

      The typical argument of the typical slashdot reader.

    2. Re:Hey by Poorcku · · Score: 1

      This is how pop psychology, urban myths mix together. However, some of us may know differently: size matters and more importantly the width. While a Danish sample, it gives an insight. Thanks.

      http://www.springerlink.com/content/wqw46755050017 61/?p=78e25fed12e247b2865ad85a359ecb45&pi=1

      /if it doesn't work, sorry .....but at least the reference is there :)

      --
      I take my children to see Madonna(..), but I never for once ever thought I was in the same business.Chris Rea.
    3. Re:Hey by tgrigsby · · Score: 2, Funny

      It's not the size that matters. It's how you use it.

      That's not what your girlfriend told me last night...

      (sorry, couldn't resist...)

      --
      *** *** You're just jealous 'cause the voices talk to me... ***
    4. Re:Hey by vraa · · Score: 1

      I'm going to be honest, I am new here -- but I have to point this out I thought we weren't allowed to have girlfriends on Slashdot?

  4. iTWire Strikes Again by Anonymous Coward · · Score: 2, Insightful
    I don't think it's the largest, at least larger are being constructed. Most lists of large telescopes are measured by aperture (making the GCT third) and while the article notes the problem that other large telescopes can't use their full mirror potential, it neglects to mention that it will be destroyed by the two mirrors on the LBT. According to a BBC article,

    The twins can also be made to work in tandem - as a so-called interferometer - which allows them to mimic a larger telescope that is 85m (279ft) wide. It's funny how I can submit a story only to have it rejected then have it accepted as two different stories the next week.
    1. Re:iTWire Strikes Again by OriginalArlen · · Score: 3, Informative
      Whilst faking a huge mirror using interferometry (see also Gemini North and South) gives you resolution, but it won't give you the photons. You've got a huge light bucket, but you're squinting through a couple of eyeholes drilled in the bottom.

      Now, if you want to talk about genuinely huge telescopes -- the GCT is only slightly bigger than the Kecks, after all -- the planned OWL (Overwhelmingly Large Telescope) is probably what you're looking for.

      --

      Everything I needed to know about life, I learnt from Blake's Seven
    2. Re:iTWire Strikes Again by Ohreally_factor · · Score: 3, Informative

      If one wanted to be pedantic, one could point out that there are other, non-optical (i.e., radio) telescopes that are much larger.

      --
      It's not offtopic, dumbass. It's orthogonal.
    3. Re:iTWire Strikes Again by Anonymous Coward · · Score: 0

      On could also point out that the calling the OWL 'planned' is quite an overstatement.

    4. Re:iTWire Strikes Again by Anonymous Coward · · Score: 0

      OWL won't be built in the near future, ESO accepted the smaller, ELT proposal (40 meter range).

    5. Re:iTWire Strikes Again by Yendys · · Score: 1

      The largest moveable (rotating against the sky) telescope (loosely defined) is the Green Bank Telescope (radio) in Green Bank, WV. I was just there.... Its enormous... Imagine a satelite dish that u can fit two football fiends in...

    6. Re:iTWire Strikes Again by Anonymous Coward · · Score: 0

      Damn those football fiends! Damn them!

    7. Re:iTWire Strikes Again by tedshultz · · Score: 1

      The 'optical' component of the IceCube http://en.wikipedia.org/wiki/IceCube_Neutrino_Dete ctor neutrino telescope is 1 km, by 1 km by 1 km. That is several orders of magnitude larger than this telescope.

  5. I can but dream by OriginalArlen · · Score: 1

    Only yesterday I was looking longingly at the Meade site and wondering if I could possibly justify a whole eight inch LX200 rather than one of those little ETX series things - I can't help thinking they're the equivalent of desktop routers vs a Cisco 6500. In theory the recent drop in the dollar should make them effectively half price (as I'm in the UK and £1 == $2.03 or so today). Sadly it doesn't seem to work that way :(

    --

    Everything I needed to know about life, I learnt from Blake's Seven
    1. Re:I can but dream by UnxMully · · Score: 1

      Amen to that. I thought the price of Software in the UK was bad compared to the US until I looked at 'scopes which manage to run it close. My Celestron 6inch SCT cost £699 over here and Celestron have it on their site with a $150 rebate bringing it down to $936 or about £470. As I recall the LX range is even worse :(

    2. Re:I can but dream by Anonymous Coward · · Score: 0

      You can buy it directly from the Chinese factory for a quarter of the price. Shenzhen
        812882.

    3. Re:I can but dream by UnxMully · · Score: 1

      I suspect one-off telephone sales may not be high on their list of priorities.

    4. Re:I can but dream by OriginalArlen · · Score: 1

      Hmmm, you may know the answer to this then -- is there any particular reason I couldn't pay dollars and have it shipped over the Atlantic?

      --

      Everything I needed to know about life, I learnt from Blake's Seven
    5. Re:I can but dream by ChrisMaple · · Score: 1
      Buy used. In my experience, you can get an instrument that is as good as new for half the price. Just be sure you examine it before you buy.

      You might not want to spend the money on a computerized drive, but you do want some sort of motorized drive so that you don't have to continually reposition the scope. If you're going to do astrophotography, you definitely want a drive.

      If you're up for a real challenge, grind your own mirror.

      --
      Contribute to civilization: ari.aynrand.org/donate
    6. Re:I can but dream by Belacgod · · Score: 1

      Have you got a friend in the States? I'd gladly offer to take it and ship it to you, but I don't actually know you so you might not want to trust me with it.

    7. Re:I can but dream by Rei · · Score: 1

      I recently got a "fixer-upper" scope, and I've been pretty happy with it so far. I've started with a Meade DS 2130-ATS. Since it was an unpopular scope, it's dropped from the original retail price of nearly 400$ down to ~$165 including shipping. That is a newt, 130mm (5 1/8th) aperture, a quality 127mm primary, with a motorized equatorial mount and Autostar guide system.

      Why was it unpopular? A couple of reasons:

        * Poor quality 1" eyepieces that come with the scope.
        * Need an adapter for 1.25" eyepieces
        * Weak tripod lock

      On the other hand, for the price, it's surprisingly well built. There's very little plastic on the thing -- lots of nice powder-coated metal. Well built enough that it was still perfectly collamated when it arrived. It's an attractive scope, too. The autostar is a pretty darned impressive tool; never ceases to amaze me. Of course, it doesn't get you completely out of knowing your stars; you need to know your bright stars in order to align the system. However, don't be fooled by the remote that looks simpler than a TV remote; it has a scrolling text display, an extensive database of scrolling information, even features to identify what you're looking at. My favorite feature is the best-of tour; it takes you to look at things that you never would have thought of looking at on your own, based on what is optimal for that evening. It has all sorts of satellite tracking features, too.

      The "negatives" are why I consider it a "fixer-upper" scope. I've got some incoming Antares eyepieces and an eyepiece adapter, so that should give me some higher quality views. I've also got a T-ring, with camera-adapter incoming, so I can do long exposures to see dim objects (my camera hooks up to a TV, too, so I can enlarge the view if desired). Don't have any cash left for filters yet, but that's just because I'm cheap and gave myself a tiny starter budget ;) That'll just be improvements for the future.

      As far as toting it around goes, it's lightweight (18lbs) and with the tripod folded back, fits comfortably under your arm like a bazooka. The only problem is that due to its length, it's awkward to fit through doors in this configuration.

      As far as difficulties go, I'm down to just one problem: pointing accuracy. When it slews, it doesn't hit its targets accurately. They're usually on the edge of the eyepiece or sometimes even not in the view. Not a problem for bright targets, but for dim targets like nebulae, it's problematic. I'll probably end up having to lubricate the joints or something; I'll look up what to do when I get a chance. Hope I get my eyepieces, adapter, and fix this bug within the next few weeks, because I'm bringing the scope up to the rockies. Should get some great views there!

      --
      The yellowcake is a lie.
    8. Re:I can but dream by PeterAitch · · Score: 1

      Check out http://orionoptics.co.uk/ - made in the UK, priced in pounds, very high quality, and you can even take the scope back to Crewe yourself if you have any major issues. Not as sexy in specification as some, but excellent optics (Sky at Night group test winners etc.) Avoids the 1$=£1 scam by definition.

    9. Re:I can but dream by PeterAitch · · Score: 1
    10. Re:I can but dream by OriginalArlen · · Score: 1

      Good tip, I wasn't aware of them. On a quick look, they don't seem to do S-Cs.

      --

      Everything I needed to know about life, I learnt from Blake's Seven
    11. Re:I can but dream by Rei · · Score: 1

      Er, sorry -- 2130-AT, not ATS.

      --
      The yellowcake is a lie.
  6. hexagonal? by number6x · · Score: 1

    OK.

    I was going to moderate as 'flamebait' but then figured I would ask.

    Did you intentionally chnage the word hexagonal from the original article or was it a strange aouto-correct error?

    If so, you need to ad the word hexagonal to your dictionary.

    Otherwise, you have a very strange sense of humor.

    1. Re:hexagonal? by Experiment+626 · · Score: 3, Funny

      Did you intentionally chnage the word hexagonal from the original article or was it a strange aouto-correct error?

      I had a telescope with "12 homosexual segments of the primary mirror for testing and observations" once. Unfortunately, all it was good for is observing Uranus.

  7. No, it's not the world's largest telescope. by CanSpice · · Score: 4, Informative

    It's not the world's largest telescope. There are plenty of telescopes that are larger than this. The James Clerk Maxwell Telescope is about 5 meters in diameter larger. Arecibo is about 295 meters larger.

    And then you've got the array telescopes like VLA and VLBA, if you wanted to get pedantic about effective telescope size.

    1. Re:No, it's not the world's largest telescope. by Penguinisto · · Score: 1
      They kinda forgot about the whole optical vs. radio thing, didn't they?

      OTOH, does interferometry(?) count when you're announcing the world's largest optical telescope (as in, singular instrument, which I believe is assumed here)?

      /P

      --
      Quo usque tandem abutere, Nimbus, patientia nostra?
    2. Re:No, it's not the world's largest telescope. by Ambitwistor · · Score: 4, Informative

      TFA (as opposed to the Slashdot summary) says it's the largest visible/infrared telescope. None of the telescopes you've listed are in that category.

    3. Re:No, it's not the world's largest telescope. by UnxMully · · Score: 1

      I'm presuming that there should have been an optical qualification in TFA as the ones you list appear, to my untutored eye, to be radio telescopes.

    4. Re:No, it's not the world's largest telescope. by Anonymous Coward · · Score: 0

      I think it's reasonable to say that when "telescope" is unqualified, "optical" is implied. Basically a radio telescope is not a telescope, especially after all the "dwarf planet is not a planet" brainwashing.

    5. Re:No, it's not the world's largest telescope. by Anonymous Coward · · Score: 0

      TFA (as opposed to the Slashdot summary) says it's the largest visible/infrared telescope. None of the telescopes you've listed are in that category. That is only because your pathetic eyes can't see radio waves. You silly humans are always making crazy distinctions between arbitrary frequencies of electromagnetic waves.
    6. Re:No, it's not the world's largest telescope. by mythosaz · · Score: 3, Informative

      Doesn't matter.

      It's still not the largest optical telescope. SALT is 11.1m and is, like GTC, made of an array of mirrors. The LBT is 2x8.4m mirrors for an effective 11.8 aperture. Also "bigger" than GTC.

      Sure, the LBT isn't fully functional, but neither is GTC.

      SALT is fully operational. SALT is bigger. Article is WRONG.

      http://en.wikipedia.org/wiki/List_of_largest_optic al_reflecting_telescopes

    7. Re:No, it's not the world's largest telescope. by CanSpice · · Score: 1

      This is Slashdot. Slashdot got the story incorrect. If TFA had it incorrect I would've left a comment over there. Since they didn't, I didn't.

      Forgive me to trying to correct the writeup on the site on which it appeared.

    8. Re:No, it's not the world's largest telescope. by Anonymous Coward · · Score: 0

      Great clarification, for one moment I just thought you were one of those pedantic Americans that refuse to believe it may be something better (of bigger) that hasn't been created, invented or deployed by the US.

    9. Re:No, it's not the world's largest telescope. by Belacgod · · Score: 1
      The most powerful telescope in the world is in the USA.

      It's Chuck Norris's eyes.

    10. Re:No, it's not the world's largest telescope. by patchvonbraun · · Score: 1

      Not entirely fair comparing radio telescopes to optical ones here. The radio telescopes are
          *much* larger because the wavelenghts are so much larger, so to match their optical cousins
          in *resolution*, they need to be bigger (either directly, or through aperture synthesis).

      Now, the radio telescopes have much larger sensitivity--they have much larger effective apertures
          than any of the optical telescopes we're talking about here. Many interesting astrophysics
          objects have little, or no, optical signal, but produce detectable amounts of radio waves.

      My modest radio telescope here at home is 3.8M in diameter, and can easily detect Cygnus A--which
          is thought to be about 750million LY from here!

    11. Re:No, it's not the world's largest telescope. by Anonymous Coward · · Score: 0

      So you're just saying "it's not the size, it's how you use it"?

    12. Re:No, it's not the world's largest telescope. by matmota · · Score: 3, Informative
      Well, TFA does mention SALT (South African Large Telescope):

      It is interesting to note that the Hobby-Eberly Telescope, also in the United States--near Fort Davis, Texas in the southwestern part of the state--and the South African Large Telescope have larger mirrors but only a portion of each mirror is able to be used when making observations.
      You might disagree with their interpretation, but they did take the other telescopes into account.
    13. Re:No, it's not the world's largest telescope. by edunbar93 · · Score: 1

      If you want to count it that way, then Keck beats the LBT, with two 10m mirrors working together as an interferometer.

      --
      "No problem. I have the capacity to do infinite work so long as you don't mind that my quality approaches zero."-Dilbert
  8. Meades are toys. by Anonymous Coward · · Score: 0

    If you can afford it, consider an instrument from http://www.rcopticalsystems.com/ or http://www.opticalguidancesystems.com/ogstele.htm/ .

    1. Re:Meades are toys. by node+3 · · Score: 2, Interesting

      That's just about the absolute *worst* advice you could give. Someone is interested enough in astronomy to consider a telescope costing a few hundred dollars, but is having trouble justifying the cost, and you tell them to buy a $15k[*] scope?

      Your condescending "Meades are toys" translates to "stay away from astronomy". If someone is interested in the sky, there's nothing better than for them to buy an inexpensive telescope or a nice pair of binoculars. That's an investment even the most casual of interested parties can feel comfortable with. Maybe their interest will fade, but they'll at least have had some exposure, which is better than the none they'll get if they don't buy a telescope at all.

      On the other hand, they might become quite enthusiastic, and find their trusty old Meade is no longer sufficient. In that case, they may very well decide to move beyond their "toy" telescope (which is nothing of the kind) and make the massive investment in a higher quality scope. But the time for that is much later.

      Public participation in science is low enough as it is. Suggesting a $15k - $50k+ initial investment, and ridiculing more reasonably priced tools which are *vastly superior* to anything Galileo had ever used is most certainly not the way to go about correcting that. In fact, it seems quite obvious that it will have the exact opposite effect.

      [*] $15k is the cheapest scope. They don't list the prices of the most expensive ones, but the highest price they list is $54k! And they suggest a finder scope that's just shy of $3k! For the finder scope! That really seemed like sound advice to you?

  9. What would Freud say about that? by A+non-mouse+Coward · · Score: 0, Troll

    Telescope envy?

    Before you mod me insensitive clod, keep in mind that we have spent $Billions to try to find other worlds outside of our own because we can't get along with the nation a thousand miles away, let alone the bloke next door. We search for ways to sustain life in celestial places with no water and no atmosphere because we think we're going to ruin ours, yet it doesn't dawn on us that if we ruin ours we will have already found a place with no water or oxygen-rich atmosphere! Say what you will, but this is definitely escapism.

    --
    libertarian: (n) socially liberal, financially conservative; neither left, nor right.
    1. Re:What would Freud say about that? by ChaoticLimbs · · Score: 1

      The reason we look for things in the heavens is because it gives us a larger-scale observation than the close up images we get of the way things work from down here. Just imagine how difficult it would be to study a nuclear submarine from the inside, whereas a picture taken from the outside would tell you what you were inside of. Otherwise, you would see passages, pipes, wires and apparatus but it would take a while to figure out what that all did if you'd never seen a submarine before (and were new to the concept).

    2. Re:What would Freud say about that? by joto · · Score: 1

      I disagree. The reason we "look for things in the heavens", is the same reason we look for things just about anywhere else. It doesn't matter if it's significant or not, or if anything useful will come out of it. What's important is that by looking, we satisfy our own curiosity.

    3. Re:What would Freud say about that? by R2.0 · · Score: 1

      It is the height of hubris to assume that only humans can wreck a planet. A large comet or asteroid doesn't give a rat's ass about whether it will be destroying humanity or dinosaur-ity when it hits. The rest of the universe is quite capable of destroying the earth without any human participation; why should we not look for a way to get out of Dodge?

      --
      "As God is my witness, I thought turkeys could fly." A. Carlson
  10. DSP? by robertchin · · Score: 1

    Why do they need to change the shape of the mirror? Why can't they just correct the problem using DSP after the fact? Presumably if you know how the atmosphere distorts while taking the image, you can apply the inverse kernel later on...

    1. Re:DSP? by Penguinisto · · Score: 1

      Why do they need to change the shape of the mirror? Why can't they just correct the problem using DSP after the fact? Presumably if you know how the atmosphere distorts while taking the image, you can apply the inverse kernel later on...

      Might be for resolution reasons... from an engineering standpoint, it appears to be more feasible to make minute modifications on a big honkin' mirror, than to try and make changes based on what a much smaller CCD picks up off of it.

      That and I suspect that it would allow them to use non-digital gear (okay, film) to record with the exact same result of data intake, or to swap out visible CCD's with infrared (w/o the additional expense and duplication, or in calibrating between the two different sensors, etc).

      Just some offhand guesses though.

      /P

      --
      Quo usque tandem abutere, Nimbus, patientia nostra?
    2. Re:DSP? by ChaoticLimbs · · Score: 5, Informative

      The reason you can't do this is because the purpose of the telescope is light amplification and magnification. The magnification could maybe work without adaptive optics, but if the light from the object does not get intensified by the large amount of reflector area applied, then you end up with dim images. It's also difficult to get sharp images with DSP as the light coming in contains more information than the sensor can send to the DSP. If the DSP instead applies corrective measures to the optics, you capture the image on the CCD better than if you applied it to only the data. It's a matter of losing the data which is NOT gathered by the CCD as a result of atmospheric distortion which prevents such an approach.

    3. Re:DSP? by NixieBunny · · Score: 1
      The distortions that adaptive optics corrects for result in the light from two places in the sky ending up on the same pixel of the detector array. That's rather hard to correct for with DSP, since you don't know which sky pixel to put that CCD pixel's photons into.

      There are plenty of problems with adaptive optics, however. The folks I work with who work on the LBT say that they've managed to crack four secondaries in a row, with zero intact ones in existence. This is not surprising, given the secondary mirror's 1 meter diameter and 1.6mm thickness.

      --
      The determined Real Programmer can write Fortran programs in any language.
    4. Re:DSP? by TapeCutter · · Score: 1

      "Presumably if you know how the atmosphere distorts while taking the image"

      The light that forms the image may take hours or even days to accumulate. The distortion is dynamic and will randomly wander about the place during the exposure period, meaning that many pixels will be erroneously "overwritten".

      In other words the photons collected by the CCD cannot be used after the fact to "know how the atmosphere distorts while taking the image" because the distortion is also a function of time.

      --
      And did you exchange a walk on part in the war for a lead role in a cage? - Pink Floyd.
    5. Re:DSP? by Have+Brain+Will+Rent · · Score: 1

      Of all the reasons given in this thread the parent's seems to be the only really accurate one. Adaptive optics works by, for example, looking at a target star (or other object I suppose) and seeing how the image changes due to atmospheric effects, and using that data to predict how the image of the larger field will change. If you are looking for an effectively instantaneous sample then there i s no reason you couldn't achieve the same effect through post-processing of the image. It's when, as the parent says, you are capturing over long time periods to let photons accumulate in each sensor cell, that post processing can't do the same thing. Although if every "pixel" in the sensor were capable of triggering of a single photon, e.g. a photomultiplier, then there is no reason you couldn't achieve the same effect as adaptive optics for long exposures by post-processing multiple frames.

      --
      The tyrant will always find a pretext for his tyranny - Aesop
    6. Re:DSP? by TapeCutter · · Score: 1

      Thanks for the vote of confidence :)

      "(or other object I suppose)"

      As I understand it the wobble mirror can use a reference star outside the field of view, it's not bound by the target. Theoretically you could use post-processing to build an image but the reason I like wobble mirrors is their engineering "elegance" makes all that complexity redundant.

      --
      And did you exchange a walk on part in the war for a lead role in a cage? - Pink Floyd.
  11. Re:Shatner? by Penguinisto · · Score: 1

    I wonder if they'll be able to use this to find William Shatner's career?

    They already found that, but it required that they use the Big Ear, and listen for the source of a faint but recognizable "Khaaaaan!" that's been reverberating about the galaxy for awhile now.

    /P

    --
    Quo usque tandem abutere, Nimbus, patientia nostra?
  12. Advice from a (sort of) newbie astronomer by amstrad · · Score: 5, Informative
    My opinion: Keep the cheaper telescope and have more money to spend on accessories such as

    1. Zero power viewfinder, since the Meade 6x30 is worthless. I use a Telerad. They are great and cheap.
    2. A good 8x50 viewfinder. I use an Antares 8X50 Right Angle Erect Image finder.
    3. A good set of quality eyepieces (you can never have enough)
    4. Some filters (light polution, moon, solar, planetary)
    5. decent, but not expensive, pair of field binoculars
    6. etc. I could go on for ever...

    You might be disappointed if you wait a year, buy the more expensive telescope and have no money left over to buy upgrades.

    Some other points:

    • The best telescope you can buy is the one that you will actually use. My first telescope was an 8" equatorially mounted newtonian. I regret buying such a big and bulky scope. It was so akward to actually get to a field. A pair of tripod mount binoculars might have been better for me as a beginner.
    • I suggest not getting all the fancy computer driven stuff. A good star chart and viewfinder can be much more satisfying. If I can convince you of that then you could get more aperture for the same price with a Dobsonian style telescope.
    • Don't fixate on magnifying power. More important is optical clarity and aperture. If you really want magnifying power, you will need more aperture since they are linearly related (google Dawes Limit). Remember this rule of thumb: 50x per inch of aperture.
    • Plan your star gazing nights. Have a list of objectives for each night you go out. Know what's in the sky that night and what you want to look at. Don't simply set up the scope and "surf the sky".
    • Log your observations in a notebook. This will help you become a better observer.
    1. Re:Advice from a (sort of) newbie astronomer by UnxMully · · Score: 1

      Keep the cheaper telescope and have more money to spend on accessories such as...

      No argument with most of what you said but I disagree on cheaper scopes if it means a smaller aperture.

      With telescopes aperture is everything, the bigger the better. A few quid saved on aperture for some accessories will soon be regretted when you find you should have gone for the light gathering power of an 8'' as opposed to a 6'' or 6'' as opposed to 4''.

    2. Re:Advice from a (sort of) newbie astronomer by amstrad · · Score: 2, Informative

      Of course you should always buy as much aperture as you can afford, but your aperture budget shouldn't cut into your accessories budget. What I was really saying was: if you are torn between two scopes of the same aperture, buy the cheaper one (i.e. buy a Dobsonian over a Mak)

      However, if you look at planets or the moon, a small aperture high focal length scope is better than the opposite. I moved to urban sprawl, so I can't view deep sky stuff. My 8" Newt is mostly useless. If I could, I'd trade it in for a good 4" high focal length refractor.

    3. Re:Advice from a (sort of) newbie astronomer by UnxMully · · Score: 1

      Of course you should always buy as much aperture as you can afford, but your aperture budget shouldn't cut into your accessories budget. What I was really saying was: if you are torn between two scopes of the same aperture, buy the cheaper one (i.e. buy a Dobsonian over a Mak)

      I can go with that.

      However, if you look at planets or the moon, a small aperture high focal length scope is better than the opposite. I moved to urban sprawl, so I can't view deep sky stuff. My 8" Newt is mostly useless. If I could, I'd trade it in for a good 4" high focal length refractor.

      That's the problem I face, light pollution that is. And too much light from the surrounding buildings. I need to find somewhere relatively secure, dark and close by. In SE London that's going to be a challenge :(

    4. Re:Advice from a (sort of) newbie astronomer by OriginalArlen · · Score: 1

      great advice! though, as I have a three foot high pile of Sky & Telescope & "Astronomy" here, & speaking as a ten-year veteran armchair astronomer - I have more advice for the beginner observer than I know what to do with ;) (actually the tip about planning what to look at and logging stuff is new to me & sounds good.)

      --

      Everything I needed to know about life, I learnt from Blake's Seven
    5. Re:Advice from a (sort of) newbie astronomer by zippthorne · · Score: 1

      I've always thought that one simpson's episode had it right, but they went too far. Just pick 10 or 15 "light-holidays" a year and turn everything off. Make sure everyone knows about it, and try to make it convenient. Allow low-intensity "glow" style outdoor lighting where safety requires it.

      --
      Can you be Even More Awesome?!
    6. Re:Advice from a (sort of) newbie astronomer by syousef · · Score: 1

      Good advice there.

      Department store telescopes are the pits. A good spotting scope is more use, particularly if you're going to be interested in bird watching (the flying kind, not the arrested if ).

      Particularly good advice to buy a Dob. 8" to 12". In my opinion 10" is just right, particularly if you have a large car and don't have medical issues that prevent you carrying some weight (but get a trolley anyway!) Much larger than 10-12" and you need a trailer or Van, or you need to get to you need to align your telescope (Harder to align a telescope if you have to take it apart)

      A zero power finder - Telrad or (can't remember the other one I have)....Oh and get a laser collimator and learn to use it early on. No point in spending money on all that metal and glass only to look through a blurry non-aligned piece of rubbish.

      --
      These posts express my own personal views, not those of my employer
    7. Re:Advice from a (sort of) newbie astronomer by Anonymous Coward · · Score: 0

      Nice thread here.

      I have more than a foot of S&T, Astronomy :-) but I like to scan the skies whenever possible. As my experience comes from relatively small instruments, I have to say that Quality and not Quantity is more important. OK a C14 was great at the mountain top but you need 2+ people to carry it around!

      You can buy a great 16" Dob but be frustrated all the time if the mount is toy-like or the focuser is flimsy. You guys already know.

      I suggest settling first on what you want to see and how much you wanna spend. Then try to find an instrument that's easy to use. And a set of good eyepieces, not necessary from the big (= expensive) brands.

      Clear skies to all!
      Anonymous "Stargazer" Coward

    8. Re:Advice from a (sort of) newbie astronomer by trianglecat · · Score: 1

      Or... have a listen to episode 33 of AstronomyCast. All about buying and using a telescope.

  13. Distortions by TheBearBear · · Score: 1

    I always wondered how astronomors calculate for distortions, or even realize if there are distortions to their calculator. Like the light data they receive from other galaxies far far away. How do they know if the light went through some medium that cause it to slow down, then went fast again, or if what they are looking at is actually a mirror galaxy that's reflecting something else, mirages, weird anomalies and physics that we sitll dont understand, or any other spacial distortions between here and there that might screw with data

    1. Re:Distortions by Anonymous Coward · · Score: 0

      Shh...those are the dirty little secrets they don't teach in all those years of grad school.

    2. Re:Distortions by Gregb05 · · Score: 1

      They fire a reference laser into the sky and correct based on that.

      --
      --
    3. Re:Distortions by Anonymous Coward · · Score: 0

      No, that's what you spend nearly all of grad school learning. Trust me on this.

    4. Re:Distortions by bvimo · · Score: 1

      Do these scientists have to wait for the laser to return from the galaxy far, far away and won't it take some time :)

      --
      In either case, here at Microsoft, we feel standards are important. And we have fun, too. Doug Mahugh, Microsoft
    5. Re:Distortions by Gregb05 · · Score: 1

      Considering they're looking for atmospheric distortion,





      No.

      --
      --
  14. Well done! by Shag · · Score: 2, Interesting

    I've been waiting for this to be completed, since I sometimes work at the W.M. Keck Observatory on Mauna Kea, and the GTC is based on (and only slightly larger than) Keck I and II.

    Keck held the "world's largest" title (among optical scopes) for the last 15 years; it'll be interesting to see whether anything steals the crown from the GTC in the near future.

    --
    Village idiot in some extremely smart villages.
    1. Re:Well done! by Nyeerrmm · · Score: 1

      The Giant Magellan Telescope, which is being sponsored by a number of universities, is slated to be 24.5m diameter, with a pretty good fill factor (I think around 80%) is significantly larger and seems to be steady enough politically to survive.
      http://en.wikipedia.org/wiki/Giant_Magellan_Telesc ope [wikipedia.org]

    2. Re:Well done! by Shag · · Score: 1

      Indeed. But since the mirrors aren't segmented a la Keck, it's kind of hard to decide whether it has 1 mirror or 7. :)

      Bring on the (segmented) Thirty-Meter Telescope, I say.

      --
      Village idiot in some extremely smart villages.
  15. During the daytime ... by Anonymous Coward · · Score: 1, Funny

    During the daytime the telescope is used as a webcam for a local beach.

    1. Re:During the daytime ... by MDMurphy · · Score: 2, Funny

      During the daytime the telescope is used as a webcam for a distant beach

  16. Mod parent's answer up, not mine. by Penguinisto · · Score: 1
    Better explanation all around. Thx muchly.

    /P

    --
    Quo usque tandem abutere, Nimbus, patientia nostra?
  17. At last! by Xeth · · Score: 1

    Fresh wallpapers for our desktops!

    Seriously though, it's both incredibly funny and somewhat sad that that seems to be the Hubble's greatest legacy. Still, I'll happily drink to continued scientific progress funded by people's desire for cool pictures.

    --
    If your theory is different from practice, then your theory is wrong.
    1. Re:At last! by Jugalator · · Score: 1

      Seriously though, it's both incredibly funny and somewhat sad that that seems to be the Hubble's greatest legacy.

      To a science amateur or geek, sure, but not to an actual space scientist, thank god.

      --
      Beware: In C++, your friends can see your privates!
  18. First shot! by sl70 · · Score: 2, Funny

    There's a great image of the first shot taking with the telescope here

    --
    Thank God I'm an atheist!
    1. Re:First shot! by ColdWetDog · · Score: 1

      That's obviously a fake. Everybody knows that telescope pictures are upside down.

      --
      Faster! Faster! Faster would be better!
  19. Satellite Image of the observatory by Pigeon451 · · Score: 3, Interesting
    http://maps.google.ca/maps?f=q&hl=en&geocode=&q=La s+Palmas,+Spain&ie=UTF8&ll=28.756363,-17.891933&sp n=0.001712,0.002942&t=h&z=19&om=1

    Pretty cool, you can zoom right in. Guess we'll have to wait for Google to scan the Earth at night so we can see it exposed ;).

    1. Re:Satellite Image of the observatory by Anonymous Coward · · Score: 0

      In case you have a problem with that link,
      here's the short version -
      http://tinyurl.com/yshlad

    2. Re:Satellite Image of the observatory by Anonymous Coward · · Score: 0
  20. Hey!!! by pablo_max · · Score: 0, Offtopic

    I can see my house from here!

  21. Grand Canary Telescope finds Big Bird by billstewart · · Score: 1

    Apparently Big Bird isn't identical in all the Sesame Street franchises - the version from Spain had "a tall, pinkish female bird called Gallina Caponata". But if you're looking for a Grand Canary, and you've got a big telescope, he's probably what you needed...

    --

    Bill Stewart
    New Fast-Compression-only CPR http://preview.tinyurl.com/dy575ks
  22. Today's logic lesson by Anonymous Coward · · Score: 0


    The world's largest telescope is ALWAYS "up and running." If it weren't, it wouldn't be the world's largest telescope.

    Think about it, please.

  23. Why Earth telescopes? by Jugalator · · Score: 1

    I thought they were starting to need so much power that the atmosphere was too much of a hurdle, and that's why telescopes like Hubble was built.

    So why are they building this one now and not e.g. helping fund the James Webb Telescope or perhaps some other upcoming plan?

    Is there still much left to discover from the surface of Earth?

    --
    Beware: In C++, your friends can see your privates!
    1. Re:Why Earth telescopes? by Sperbels · · Score: 2, Interesting

      Adaptive optics are overcoming the problems with imaging through the atmosphere. And since you brought up Hubble... all you Hubble-repair-mission fanboys out there might take into consideration that sending up the space shuttle costs somewhere between $500 million and $1.5 billion (depending on who you ask). Now consider that this telescope cost $180 million to build. Can you imagine what kind of ground based optical telescope you could make for $1.5 billion? It would outperform Hubble by leaps and bounds.

    2. Re:Why Earth telescopes? by Carnivore · · Score: 1

      Yup, you're correct. There are still things that you can't do on the ground (wavelengths that our atmosphere absorbs) but for the price, ground-based AO observing is very, very good.

      Also, remember that the JWST is not serviceable. If its mirror doesn't unfold, well, that's it. The GTC has 6 spare segments so that a rolling re-aluminising can be done.

    3. Re:Why Earth telescopes? by ChrisA90278 · · Score: 1

      Why build ground based telescopes?

      (1) They are MUCH cheaper then space telescopes. Maybe 20X cheaper. There ground based scopes only cost as much as a few Hollywood blockbuster movies. We can't afford more then about one space telescope per decade so this means there is more demand for time then a space telescope can supply

      (2) ground based scopes can be very much larger and collect more light

      (3) Adaptive optics combined with the large size means the images are about as sharp from the ground as from space. So we get same result but as 1/20th the cost

      (4) the air is non transparent as some wave lengths and you simply can't see through it from the ground. At these wave lenths a space telesciope is the best or only option.

      The bottom line is that you want both ground and space based telescopes because they are complementary.

  24. I work for an astronomy department... by Carnivore · · Score: 2, Interesting

    And I'm getting a kick out of these replies...

    No, really! I work for the University of Floriday Astronomy department. The department has a 5% share of the GTC, and we're looking into another 5%. That may not seem like much, but if you consider one night of 10 meter time can be enough data for a graduate thesis, it's a massive amount of time.

    The IR instrumentation group in my building is building a _giant_ instrument for the GTC. It's called FLAMINGOS-II. IR is where it's at in astronomy right now, so it's neat to be in an up-and-coming department.

    If you guys have any questions about the telescope, I'll do my best to answer them or find out for you.

    1. Re:I work for an astronomy department... by Anonymous Coward · · Score: 0

      Photos of first-light, Telescope control testing (Writing GTC using Tycho as a pen!), and a beatuifull photo with a lo-res testing camera to UGC 10923 galaxy.
      Here:
      http://www.iac.es/divulgacion.php?op1=16&id=455

  25. Largest? by sxeraverx · · Score: 1

    Isn't the world's largest operational telescope always up and running? There may be a new largest, but the old one was the largest back then as well, as were all the ones before it.

  26. NO PHOTOS TAKEN OF THE UNIVERSE!!! by Anonymous Coward · · Score: 0

    NO PHOTOS TAKEN OF THE UNIVERSE!!!

    World's Largest Telescope takes 0 photos!!! Doesn't work!!!

  27. why Gran Canaria over Tenerife? by aapold · · Score: 1

    Wonder why they used Gran Canaria over Tenerife right next door, which has a peak almost twice the height as the highest on Gran Canaria, with Pico Teide being comparable to Mauna Kea... I mean I guess logistically building it might have been easier as it wasn't as steep, but I thought part of the point was to avoid as much atmosphere as possible...

    --
    "Waste not one watt!" - CZ
    1. Re:why Gran Canaria over Tenerife? by gsliepen · · Score: 1

      It's not on Gran Canaria, it's on La Palma.

    2. Re:why Gran Canaria over Tenerife? by Anonymous Coward · · Score: 0

      Easy answer. The Teide is a protected place (natural park), so nothing can be built there. Also the Teide is a volcano that even is not active right now, you can still cook eggs by burying them in the ground. You wouldn't place a telescope that costed so much money on top of a volcano that some day can become active again.

    3. Re:why Gran Canaria over Tenerife? by iainl · · Score: 1

      True, but the GP has a point - Tenerife's highest point is 3717m, compared to about 2400m for La Palma. Also, anyone who has read about the megatsunami predicted from there knows Cumbre Vieja is still active, so I'm still curious about the decision. If I had to guess, it's just due to the fact that there are so many other parts of the Roque de los Muchachos Observatory already up there, combined with the fact that Tenerife is more populated, and so you'd probably get more light pollution.

      --
      "I Know You Are But What Am I?"
    4. Re:why Gran Canaria over Tenerife? by gsliepen · · Score: 3, Informative

      Sure, Tenerife's highest point is higher, but you're not allowed to build anything on the top of the Teide. The current observatories on Tenerife are approximately at the same height as those on La Palma. Yes, the vulcanoes on La Palma are still "active", but it's very benign activity, a little flow of lava once in a few decades. Those vulcanoes are also to the south of the island, while the observatories are closer to the north. The seeing quality at both sites is comparable I think.

    5. Re:why Gran Canaria over Tenerife? by XNormal · · Score: 1

      > Yes, the vulcanoes on La Palma are still "active", but it's very benign activity

      For an astronomer, there's nothing "benign" about hot air. It causes optical distortions.

      --
      Stop worrying about the risks of nuclear power and start worrying about the risks of not using nuclear power.
  28. Need to specify optical by Logarhythmic · · Score: 1

    Strictly speaking the "largest telescopes" will always be the radio telescopes, spanning several square kilometers in some cases. I know a professor at CMU who is currently designing what he hopes will be the largest radio telescope in the world. If they intended to call it the largest *optical* telescope, they really should have said that. "Largest telescope" is quite the claim.

    --
    "Before criticizing someone, first walk a mile in his shoes. Then, you'll be a mile away... and you'll have his shoes."
  29. Um, no. by edunbar93 · · Score: 1

    Especially when it comes to telescopes. Larger aperature means more light is collected for imaging, and the more light you collect the shorter your exposure times need to be. And with the limited number of telescopes in the world, multiplied by the limited number of hours actually available for observing at each one (you need a clear sky, on a night near the new moon so that the glare doesn't wash out your images), cutting your exposure times is paramount.

    Larger aperature also means higher resolution images and that dimmer and dimmer objects can be observed. When you're trying to find the very first stars in the universe, only the biggest telescopes in the world will do.

    --
    "No problem. I have the capacity to do infinite work so long as you don't mind that my quality approaches zero."-Dilbert
  30. OWL plans have been scrapped in favor of . . . by Anonymous Coward · · Score: 0

    the planned OWL (Overwhelmingly Large Telescope) is probably what you're looking for.
    The OWL plans have been scrapped in favor of the HSTAMH (Holy Shit That's A Motherfuckin' Huge) Telescope.