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Telescope Cluster For SETI
ContinuousPark writes: "MSNBC is reporting that radioAstronomers showed today the Rapid Prototype Array, which consists of seven 12-foot off-the-shelf satellite dishes, set up at the Russell Reservation near Lafayette, CA. This experiment, in which computer software will control the drive systems of the dishes and process all gathered information, is going to tell astronomers how to build much bigger radio telescope arrays such as the 1-hectare telescope and the Square Kilometer Array; the SKA would be 10 to 100 more sensitive than the Arecibo radiotelescope. Check out the SETI Institute press release and photos. "
It seems to me that, if the people behind this play their cards right, they could get a boost from amateur radio astronomers. If the plans & software for these systems were published on the net, I would imagine that a few hobbyists might actually build a small network of these telescopes in their backyards (I can just imagine them driving around scrap yards looking for abandonned dishes). Science has small questions as well as big questions, and the cumulative answers to a series of small questions can add up to something significant. I'm sure that professional astronomers could find a use for amateur collected data. I remember a story from my college days about the first paper submitted to the Astrophysical Journal on radio astronomy. The author (I'm sorry but I have forgotten his name) was not a professional astronomer; he was a technician at a radio station in a small town Illinois. The story is that Otto Sturve, who was ApJ editor at the time, couldn't find anyone to peer review the article because radio astronomy did not exist as a specialty. So he hopped a train (the ApJ is published by the University of Chicago), and paid the author a visit. He inspected the equipment and asked the author about his methodology. The he went back to Chicago and published the article. Amateurs have always played a role in astronomy. Anonymous Me (too lazy to log in)
Linux probably isn't any more suited for the job than anything else... except it will save taxpayers' money. Which is a good enough reason, IMHO.
"Free your mind and your ass will follow"
-- seti.krisjohn.net
Anyway, I think the last /. article with a mention of Radio Astronomy was in regard to the Iridium Sats, so were' not all just SETI. Other recent space science stuff has been about extrasolar planets, which just happens to be optical astronomy at the moment (planets are being found using light intensity changes and red shifts, not radio waves...)
The data can be time tagged with time from an atomic clock. The atomic clocks can be kept in sync with a GPS timing receiver.
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I read the article on the Planetary Society site, and it's not clear to me why this is a good idea. Sure, you might get a stronger signal from a narrowband laser pulse, but the sender would have to be pointing it directly at us for us to get the signal. Why would the sender decide to point it in our direction? Seems pretty improbable.
:)
Then again, if you have read more on the subject, and it isn't actually as bogus as it sounds, maybe you can enlighten us
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Oh sure, I can see it now; accusations flying of people flooding the SETI servers with dozens of virtual satellite dishes, trying to boost their team scores...
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Great, the one program that I actually WANT my tax dollars to fund and Congress decides they don't need my money.... Woohoo...
Kintanon
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Well, of course it will be a tradeoff, but probably not a bad one. Even with signal processed receiver arrays used to "aim" Arecibo, it's still limited by physical geography in a lot of ways. Needless to say, building another 300-meter instrument (at another latitude, for instance) would cost much much more than several dozen or even hundred commodity dishes with custom ultra-low noise preamps and receivers.
I'm not a radio astronomer, but it seems this will lower the entry barrier and put serious deep sky work in reach of a lot more researchers. Maybe these commodity arrays won't replace big dishes, but they certainly have the potential to accelerate research in radio astronomy.
Mozilla
My read on the article is that they are making their *own* array out of off the shelf like dishes, in order to keep costs way down. I do not see anything that says they are going to be doing 'distributed data acquisition' by linking together your and my satelite dishes. But the latter is a damn neat idea eh?!! I wonder what the challenges would be for such a thing? Probably 'tracking' and 'electronics', with everyone having different dishes and gains and stuff... It sounds like they had to do some work in order to make these things do what they want for their purposes, and now they're testing all of that... attempting to put together something that would work for all of our backyard dishes would be a lot more complicated, and there would likely be some extra cost (for someone) to 'upgrade' our dishes...
I'm recalling some of this from an Astronomy class I took over a year ago, so I don't remember a lot of the details on how this works. But if I remember correctly, it's not a case of needing 6000+ telescopes to 'equal' Arecibo. Using something called Radio Interferometry, you can have two medium-size telescopes a kilometer apart, and have them function as one big one (for an accurate, detailed description of how Interferometry works, check out this site.Examples of existing telescope arrays using this technology are the LBA and the VLBA, which I think stands for 'Long baseline Array' and 'Very long Baseline array,' where they stretch out over several miles--I think the VLBA is in New Mexico. I may have either the acronyms or the meanings messed up, but I think that's the gist of it.
What we _need_ for SETI is a LARGE radio dish on the "dark side" of the moon... sunk in a crater or something. That way the moon would filter out most of the Earth radio noise... and due to the lower gravity, it will probably be easier to build a bigger dish.
:-) That is why the space program is so VERY VERY vital to the future of the human race.... we need to spread off this planet, and into the unknown. Besides, what else is there to do? :-) j/k
I really wonder why people say "why do we keep throwing money towards SETI?"... I say why not? I mean what do we do on this world that is so great. We are here to serve life itself... finding other life is part of the duty we have.
Ryan
Do'h
I can see various applications, such as cheaper ways to communicate with satellites & space probes, cheap ways to do the "easy" radio astronomy somewhat better. (Like studying radio pulsars, etc. without using the big-time arrays), and even just for a teaching and prototyping tool.
I didn't see much mention of *that* in the MSNBC article....
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Well, from "pure" technical point of view, there's
very little "new" stuff here. The point is to figure
out a way to build them cheaply. Almost everything
in Astronomy is astronomical, especiall the cost.
For example, it will be considered a bargin if one
can build the SKA for less than half billion USD.
So to use off-the-shelf components is
essential. Those dishes may not be the best ones
out there, but you will need thousands of them
before it is done. So are the LNAs and the
Correlators, and the computing units needed.
It comes down to MONEY, 100s of millioms of
US dollars at least. If you insist on using
"cutting edge" technologies, you'll be talking
about billions of US dollars.
So, once this is fully in place, not only will they have folks all around the world crunching numbers for them, but they'll have folks all around the world listening for them as well. Now *that's* cool.
It makes sense, though. One of the arguments for helping SETI was that your computer is idle most of the time. Similarly, your satellite dish is also idle most of the time; why not make use of it?
Now, if I only had a satellite dish...
darren
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(darren)
While it is true that the energy gathering capability of the smaller dishes is much less than the large antenna at Arecibo, the resolution of the signal is not a factor of the gathering area so much as the position of the antenna. 100 12' dishes scattered over 1000 miles would act like a 1000 mile dish, except that the actally intensity of the signal would not be as great.
Gonzo
And making the thing 'expandable' is not really revolutionarry in my opinion.....
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To put this in perspective, you need to have 6,824 of the little 12 foot dishes to equal the collection area (and hence sensitivity) of Arecibo...
1)transmitted beams of visible light (ie. lasers) can be finer than beams of radio waves due to the higher gain of optical telescopes. I suppose this means that the signal can be more concentrated and thus brighter and more easily detected.
2)visible light doesn't disperse as much as radio waves. This also increases the intensity of the signal.
3)the capabilities of radio transmitters has hit a brick wall while optical lasers continue to increase in power. This is assuming that an alien race is similarly limited as to the power of their radio transmitters. All this leads us onto the question of how effective signals sent with visible light are. The answer is very. The article says that with our current technology, we can send laser transmitions that would outshine the background light from our sun by 5000 times. So assuming that an alien civilisation has more powerful lasers than us, we should easily be able to detect any signals they send in our direction.
Also, the equipment needed for an optical SETI search is very simple. All it involves is a pair of photon-detectors. Current optical SETI equipment works on the premise that any optical signals from alien civilisations will be sent in pulses. I haven't had time to purse the explanation on how the detector works so I can't tell you yet. Perhaps someone else with access to the latest Planetary Report could help out here.