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Prototype Telescopes Complete Key Test
Matthew Sparkes writes "Two prototype antennas for the world's largest array of millimeter-wave telescopes have passed a key test, working to track and image Saturn for more than an hour. Ultimately, ALMA (Atacama Large Millimeter/submillimeter Array) is expected to resolve details 10 times finer than the Hubble Space Telescope when it is completed in 2012."
Server isn't responding to me. So I ask google. cache
This post climbed Mt. Washington.
Ah, but can it image... Cassini?
That would rock.
Two prototype antennas for the world's largest array of millimetre-wave telescopes have passed a key test, working together to track and image Saturn for more than an hour on 2 March. Ultimately, ALMA (Atacama Large Millimeter/submillimeter Array) is expected to resolve details 10 times finer than the Hubble Space Telescope when it is completed in 2012.
ALMA will use up to 64 antennas and will be located in the Atacama desert, 5 kilometres above sea level in the Chilean Andes. Designed to look through dust clouds to reveal star formation, image embryonic planets and probe the early universe, it will be the world's most sensitive telescope at wavelengths of 0.3 to 9.6 millimetres - a regime obscured at lower altitudes by atmospheric moisture.
But making all of the 12-metre dishes function like a single giant telescope will be a challenge. Fibre-optic cables will link each dish to every other dish in the array, and to a giant special-purpose electronic computer called a correlator.
"It collects the amplitude and phase information from each of the antennas, and knowing their distances from each other, it lines everything up to produce a coherent picture of the source," says Jeff Mangum, an ALMA project scientist at the National Radio Astronomy Observatory (NRAO) in Charlottesville, Virginia, US.
'Fringes of the universe'
The 2 March test actually linked two prototype antennas at another observatory, the Very Large Array site in New Mexico, US, with each other and with a small-scale prototype of the correlator. But the test, called 'first fringes', bodes well for ALMA's future, Mangum told New Scientist: "It verifies that ALMA can make measurements not just as single telescopes, but as a collection of antennas, which is the primary mode of operation."
Millimetre waves are at the upper end of the radio spectrum, just below infrared radiation. They can reveal important organic molecules, but are obscured by atmospheric moisture.
Small arrays at lower elevations have probed the sky since the 1980s, but atmospheric moisture made observations difficult at wavelengths shorter than 3 millimetres. A 1990 report urged building a large array at high elevation, and the NRAO, the European Southern Observatory, and the National Astronomical Observatory of Japan later picked the Atacama site. The altitude puts the array above most of our atmosphere's water, allowing observations down to 0.3 millimetres.
Although plans call for up to 64 antennas, present funding can pay for only 50 or so dishes. The dishes will be movable, allowing baselines from 150 metres to 18 kilometres, with the longest baseline and the shortest wavelength giving resolution as fine as 0.005 arcsecond, a factor of 10 better than Hubble.
Because millimeter waves can penetrate dust that blocks visible light, ALMA's large collecting area "will make it much easier to detect very faint objects at the fringes of the universe", says Mangum.
I, for one, welcome our new overlords from outer space.
With finer details!
Censor the raw data coming from out of this too, like they have with the Hubble?
I'm a ham operator, and the signals coming from the Hubble are a jumbled mass of unintelligible garble. Further research shows they are using military hardware for secure connections.
I do understand that control codes are administered via ground, however, public key signing would allow transparency while providing a secure platform.
Why do they hide the whole data stream? What do they not want us to see?
Call me back when they complete the Turing test.
This is not your signature.
apparently, you've slashdotted Google.
---
brought to you by the CAPTCHA "flamers"
Does it run Linux?
I have no problems believing that the control data is encrypted for the hubble. For one thing, you don't want others taking it over.
As for the data, I'd imagine that it'd be compressed, encoded, and multiplexed to the point that you'd need special equipment that no normal HAM operator* would have, much less the settings needed to sort it all out and make sense of it.
For public key stuff - that's more computationally intense than private key military encryption methods. Remember, we're talking about systems where a 386 would be considered 'high end'.
*I'm not saying that you're a 'normal' Ham operator, Crawler, but we're talking the space industry here.
I don't read AC A human right
No folly is more costly than the folly of intolerant idealism. - Winston Churchill
I'm actually beginning to wonder if space-telescopes still have their use (in regard to costs/benefits). I mean, thanks to interferometry one can get the resolution (equal or better) with earth based telescopes for a fraction of the price of space-telescopes like hubble and consorts. And thanks to adaptive optics there is hardly any atmospheric blurring which smears out the pictures anymore, neither. And, since the mirrors can be bigger then those send into space, the light-gathering power is way superior for earth-based telescopes.
The only advantages left are for specific wavelengths (like near-infrared), because the atmosphere absorbs most of that, but even that is more and more debatable, now that new instruments and detectors are becomming so sensitive that they can detect and use it on Earth too. I'm wondering, with the multi-billion costs of space-telescopes, if it's really worth the money? With the same amount of money, one could make a huge interferometer-telescope with a diameter of the Earth (though it would need to consist out of many 10-meter telescopes for light-gathering purposes). I'm all for space-exploration, but what still justifies the expense of a space-telescope, if earth-bound ones can do as well for a fraction of the price?
--- "To pee or not to pee, that is the question." ---
---I have no problems believing that the control data is encrypted for the hubble. For one thing, you don't want others taking it over.
:-) .
No, of course you dont want some random joe to take Hubble over. However, they could implement in which "packets" are signed. The data would be separate from the authenticated signature. Along with that, they would want to implement a proper timecode to prevent replay attacks.
But controlling is aside the issue.
And I do hate to mince words but "normal HAM operator"... There isnt such a thing as a normal ham operator these days. Many hams specialize in one or two distinct fields of RF study. I like examining digital commms and remote communications (EME and meteor scatter).Along with my interests, I have bought that A/D board recommended by GnuRadio (normal HAM operator). All I needed was a RF front end and just to downsample to the range of the AD board (0-20 MHz).
I asked for help from some people at NASA and they said the connection was encrypted, and it does seem to be the case.
It doesnt really matter what Im required to build for receiving gear. It's all multi-purpose for us hams. And I do like the idea of splitting the transmitters from the receivers (well, you do have 2 antenna then per kit).
---I'm not saying that you're a 'normal' Ham operator, Crawler, but we're talking the space industry here.
Too true. No offense taken. Still, I can decode the majority of transmissions (the old freq shift Symbol cards are really neat under a scope) and can transmit on quite a few bands. I dont know if you've ever been in a Ham's shack, but the amount of gear they can have (and I too) is pretty immense. I just focus on the digital side a bit more
Correction: recommended by GnuRadio (normal HAM operator). All I
Damn clipboard. It was SUPPOSED TO BE (Measurement Computing PCI-DAS4020/12 A/D card).
Hubble releases public images, but much of the research is just that - research - done by labs who are trying to maintain the integrity and proprietary nature of their work. Hubble data is supposed to go to the researcher first and the public second. IIRC it's a default six month delay unless overridden by the lab collecting the data. It's not censorship so much as embargo, and it's really no different from what any researcher does in order to not be scooped on the research they're doing.
"Win treats sysadmins better than users. Mac treats users better than sysadmins. Linux treats everyone like sysadmins."
In a related news release, scientists announced that the power of Hubble is so great that it can resolve the inanity of a ham radio operator who has spent his (definitely *his*, not her) Saturday night listening to satellites pass overhead, followed by him complaining that he isn't smart enough to understand the transmitted signals.
Why not put a bunch of little telescopes in space. Best of both worlds.
Libertarian Leaning Political Discussion Forum.
In an ideal world we could just say "why argue about it?" and build both. But of course this is not that ideal world so we have to fight each other for morsels.
For instance, I'm based at a new observatory in the southern hemisphere, so I'm biased towards ground-based systems and can reel off a string of reasons why ground-based telescopes are superior (or at the very least worthy of further investment).
A friend works with the Hubble and he's completely dismissive of ground-based instruments, and can prove beyond all reasonable doubt that space-based instruments are the only way to go.
Yet another friend and colleague does much of his work from Antarctica and, as far as he is concerned, no new instruments should be built outside that continent, and all funding should go to his pet projects.
Meanwhile, guys working at other sites, often on venerable gear at places like Kitt Peak or Mt Wilson, fight just to keep their observatories open against claims by everybody else that their facilities are obsolete and a waste of funding.
The cost of allthese observatories is high. Going into space is hideously expensive and fraught with risk. Building and working in Antarctica is barely less so. Transporting components to high, remote mountaintops elsewhere is slightly easier but still difficult and costly.
But the alternative is to put all our eggs in one basket, and suffer the inevitable consequences, so we don't do that. Or even worse, we can fall victim to the ignorant who claim astronomy (in fact, all science) is worthless and a waste of money, and so have nothing.
A combination of space-based and ground-based telescopes is still the best way to go, and we'll just have to keep fighting over funds to do it that way. One decade may be excellent for space telescopes, at the expense of ground-based ones, but the following decade can be just the opposite, and that's how it's been, and probably will be in the decades to come. At least I hope so.
control data is encrypted for the hubble. For one thing, you don't want others taking it over.
I am kind of curious to see what Mr. Goatse would do with it for a day. (But tell me about it instead of show me.) Cue the Uranus jokes...
Table-ized A.I.
Some sites on Earth will always remain unaffected by light pollution, and it'll still be cheaper and easier to build and work there than in space; at least in the foreseeable future. We can build the really huge instruments on remote mountaintops, and send smaller telescopes into space to explore the spectrum unavailable to the large ground-based ones.
Here's the real question: Which will roll out first, the completion of all US television broadcasts in high definition or this thing being launched, orbiting, and operating?
Why dont you buy a telescope and see what they are trying to hide yourself?
They do share it. But they worked hard to be able to use it and they get to be in line ahead of you.
Scientists doing basic research do in fact collaborate, cooperate and compete, as it best serves the task at hand. That would explain the whole peer review process, not to mention the rampant cross-pollination of people between labs, projects, funding sources, large scale projects, etc.
The vast majority of the results do get back to the public, you benefit from them, and they are shared.
I pay my taxes too - and part of that is so that the astronomers who know what they're doing can sort out what comes back from the hubble and let me know when they find something I need to know about.
"That isnt an excuse. I (in part) paid for this damned orbital telescope, and I want the output untouched by some "research group"."
Yeah, I'm not sure the Yosemite Sam approach will get you very far. The "research group" is actually a vast collection of individual and collaborating scientists, research associates, assistants and pretty dedicated scientists who work their tails off in pretty impressive fashion. They're hardly a group deserving of derision, and there's no evil intent behind them.
In case you care to see it - here is the verbatim info from STSci on how data gets used. It's hardly nefarious:
XVI. PROPRIETARY RIGHTS TO DATA
General Observers (GOs) have exclusive access to their scientific data during a proprietary period. Normally this period is the 12 months following the date on which the data are made available to the investigator in a form suitable for scientific analysis. This policy also applies to data obtained during the Director's Discretionary time that is assigned to individual scientists. At the end of the proprietary period, data are placed in the HST archive where they are available for analysis by any interested Scientist.
Proprietary periods longer than 12 months may occasionally be appropriate for Long-Term programs if there is a need to have most or all of the data available before significant scientific results can be obtained. Other special circumstances requiring extensions of the proprietary periods may also arise for GO programs of any scope. NASA policy permits the ST ScI Director to lengthen the proprietary period by up to an additional 12 months, in cases where the Director concludes that an extension is justified. Such requests are subject to the Telescope Allocation Committee (TAC) review. Data-rights extensions beyond a total of two years are possible only when approved individually by the Space Telescope Institute Council upon the recommendation of TAC and the ST ScI Director.
GOs who wish to request a proprietary period shorter than one year, or to waive their proprietary rights, are welcome to specify this to ST ScI. Because of the potential benefit to the community at large, particularly in the case of large projects, GOs are asked to give this possibility serious consideration whenever they feel that such waivers would not be harmful to their programs.
GOs should be aware of the great public information potential of HST data. Cases may arise in which it would be appropriate to release HST data, for public-affairs purposes only, during the proprietary period. In such cases, it is hoped that GOs will cooperate with the ST ScI Office of Public Outreach in meeting the public's right to information. In no case, however, will proprietary HST data be released for such purposes without concurrence of the Principal Investigator. All PIs whose data are released for public-affairs purposes will receive full acknowledgment.
The principal investigator will endeavor in good faith to inform NASA and ST ScI of any planned press release at the earliest practical time and shall consider seriously and in good faith any comments made by NASA and ST ScI prior to the press release.
Except for images and animations produced under this Grant for which copyright shall not be asserted and except if otherwise provided in th
"Win treats sysadmins better than users. Mac treats users better than sysadmins. Linux treats everyone like sysadmins."
Hmm... My extent of satellite experience was working with 8" floppies and multiplexors at Schriever AFB years ago, and more recently training in how to configure slightly more modern multiplexors for field applications. Fun time: spending three hours troubleshooting while in chem gear only to have the instructors realize that their satellite simulator(couldn't get real sat time for the exercise) had been jarred out of position.
No, of course you dont want some random joe to take Hubble over. However, they could implement in which "packets" are signed. The data would be separate from the authenticated signature. Along with that, they would want to implement a proper timecode to prevent replay attacks.
I've learned that satellites tend to keep their control and data bands seperate, and the usage of multiplexing* is common, especially when you're talking about multiple instruments. And our demuxers run in the hundreds of thousands of dollars for our stuff, much less NASA science stuff. Remember what I said about military private-key encryption being cheaper computationally? Timing is already part of the security, and the hubble was designed back in the '80s and would have to use a system cleared for space and capable of remaining secure through decades of operation. Public key infrastructure is too new, computationally expensive, and expaning of a field. After that, it's easier to encrypt the whole channel than to worry about packets.
Are you even sure that you were trying to listen in on a data channel? From my reading it looks like the hubble stores it's data and then transmits it down in batches.
*For the uninitiated, a multiplexor takes multiple data streams and merges it into one stream, which a demultiplexor then splits back into multiple streams. For example, something like 60 voice lines, two ip networks, a crash-net(think red phone), etc... I'm sure Creepy Crawler knows this, but other readers might not
I don't read AC A human right
Ultimately, ALMA (Atacama Large Millimeter/submillimeter Array) is expected to resolve details 10 times finer than the Hubble Space Telescope when it is completed in 2012.
Great. It'll be completed just in time for the end of the world!
-Rich
How cheap/easy would it be to make a distributed radio telescope if we had lots of small systems scattered around?
I was envisioning a small unit that plugs into a PC and has GPS location ability so we know where it is in the array, and the software reports data and location back to the central system. If everyone interested in astronomy picked one up we'd soon have a big array, and it would be reasonably low cost too if everyone paid to cover some of the cost of their antenna.
I suspect if we have enough bases then localized "noise" should be easily enough filtered.
Is radio astronomy doable with thousands of small devices?
I hate to respond to a dead article, but you are spot on.
---Remember what I said about military private-key encryption being cheaper computationally?
I remember seeing special chips when I was with my dad at a naval reserve center (he's a retired chief).. One of the things Im interested in is TEMPEST and such technology dealing with EMP. What I saw was impressive: Ceramic CPUs. They wernt made out of silicon (or that look anyways) but instead they were pearlish white and said to be immune to EM pulses.
From what little I understand about TEMPEST and the government books, these chips could detect an 'event' at the beginning of the chip, and fail-over to ground the whole chip. Amazing piece of work.. However it was a 286, but guaranteed to work in high energy environments and low-shielded environments (Space).
I've even thought about going into Comm in the military just to access the powerful equipment. The things my dad can legally tell me about is just
amazing.
---Are you even sure that you were trying to listen in on a data channel? From my reading it looks like the hubble stores it's data and then transmits it down in batches.
You might have a point there... I'm not sure what to make of their data formats, nor do I have an idea of what mux they use, though I doubt it would be UWB-like... however it could be. GPS is already under the floor, and I dont see why Hubble couldnt be. From my eyes, I just saw a swath of data and I tried to process it. A bigger question is if my 16 bits/Hz is actually enough to extract real data...
I know there's a few people who make fun of me for doing this, but I find what the Hubble puts out as important as the numbers stations. By the time you try to triangulate them, they're already gone or moved.
I'm all for space-exploration, but what still justifies the expense of a space-telescope, if earth-bound ones can do as well for a fraction of the price?
I'd like to see an array of space based telescopes set out in a pattern much bigger than the Earth, perhaps at the L2 LaGrange point. That should allow us to see planets in other solar systems quite well.
I don't see how you can do that on Earth.
My God, it's Full of Source!
OUTSIDE_IP=$(dig +short my.ip @outsideip.net)
"While I understand how you might come to this conclusion, it's actually completely wrong."
:-)
:-). I thought you made a very good rebutal, and it makes it clear there is still use for space-telescopes (and as you say, those that can be done on Earth never get to space, I suppose).
/.),..."
;-p
:-) As I said earlier, it was actually an open question, to see if any interesting debate could come from it. The question is quite complex, since it involves costs versus benefits.
Well...*actually*... I didn't make any conclusion, I asked an open question.
It surprises me that the most interesting answer comes from an anonymous coward with score 0; if I had mod points, I'd mod you up. UYou should really post such things with your nick, you know
"You demonstrate enough knowledge to intelligently question the case for space (which is relatively rare actually, but probably common here on
No, not at all. I'm rather the exeption to the rule, also on slashdot.
"...but not enough to answer it."
Heh. You mean I also have to answer my own question in the same post?
"I can't let these ideas go unchallenged because the only way new missions will be funded is if lay people continue to support them."
Lay people, huh? *me coughs* Well, anyway, you might have had the impression I'm making a case against space-exploration/colonisation/etc., but actually I'm not. I'm rather pro-space (that's why I'm a member of the planetary society too). But it's a valid question to ask, just like the old human exploration versus robotic exploration.
That said, I doubt many space missions are funded because of the support of lay people, especially if it's about some exotic telescope to measure the background-radiation of the universe. I mean, really: how many people even know anything about what is send up there? I doubt 2% of the populace can name 3 current and ongoing space-projects or missions. Nah...it has more to do with politics and the perceived economic benefits it will bring. John Doe has really little influence on it. (Though, focused lobbying might help some missions, as TPS has already demonstrated.)
As for your exellent points, one small remark, though:
You claim a few times that those big earth-based telescopes could also cost 1 billion. Well, that may be true, but for that price what do you get? Both 10-meter keck-telescopes, which in conjuction can work as a 85 meter telescope (at least in respect to resolution), have costed $140 million; the HST, with a mirror of 2.4 m, has quite a different price-tag, and I quote from the wikipedia:
'From its original total cost estimate of about 400 million dollars, the telescope had by now cost over US$2.5 billion to construct. Hubble's cumulative costs up to this day are estimated to be several times higher still, with U.S. expenditure estimated at between 4.5 and 6 billion USD and Europe's financial contribution at 593 million Euros (1999 estimate).'
Now, you made very good points why space-telescopes are still useful in some specific area's, but my question (not conclusion) was more related to the cost/benefits.
I mean, looking at the real price-tags, for the amount of the HST, one could have built 25-30 keck-telescopes (with god knows what resolution with interferometry). Certainly, with such an earth-bound system, the amount of usefull data would have been staggering as well, and may have surpassed that of the HST in many aspects.
--- "To pee or not to pee, that is the question." ---
i think this is indeed the path to pursue. since the most bang for the buck is achieved by maximizing the separation, not the scale or scope of technology at each point, one could insert relatively small and relatively inexpensive twin observation platforms into the L4 & L5 Lagrange Nodes via a S.T.E.R.E.O.-like lunar loop trajectories. these two 'outriger' platforms on either side of the 'mothership' earth would provide a baseline seperation of ~1.7 AU or almost 15 light minutes. That aught to allow for a handsome degree of angular resolution. The wavelength of observation would need to be long enough to not overtax the ground based processesing speed for combination of the signals, so optical might be off the table for a decade or two, but there are plenty of very bright objects we could learn tons about in the longer wavelengths, like black holes for starters.
i think this is indeed the path to pursue. since the most bang for the buck is achieved by maximizing the separation, not the scale or scope of technology at each point, one could insert relatively small and relatively inexpensive twin observation platforms into the L4 & L5 Lagrange Nodes via a S.T.E.R.E.O.-like lunar loop trajectories. these two 'outrigger' platforms on either side of the 'mother-ship' earth would provide a baseline separation of ~1.7 AU, 258 million km or almost 15 light minutes. That aught to allow for a handsome degree of angular resolution. The wavelength of observation would need to be long enough to not overtax the ground based processing speed for combination of the signals, so optical might be off the table for a decade or two, but there are plenty of very bright objects we could learn tons about in the longer wavelengths, like black holes for starters.