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Green Bank Telescope Goes Live
ptbrown writes: "The world's largest steerable radio telescope is being dedicated today at Green Bank, W.Va. The 100 meter Robert C. Byrd Green Bank Telescope (named after a West Virginia senator) is 485 feet tall, weighs 16 million pounds, cost $75 million, took almost 10 years to build, and is expected to last for at least 25 years. The telescope it replaces (designed to last 10 years) collapsed in 1988 after only 26 years. This is a pretty unique dish: assymetrical, side-mounted feed arm, movable surface panels, and laser-assisted ranging. And they give tours, so if you're ever around southern West Virginia think about stopping by. "
This thing already discovered proof of intelligent life on other planets. Apparently it picked up a broadcast from Alpha Centauri of voices singing "Will The Real Slim Shady Please Shut Up"...
It should be operational in about 2 years. Why not use distributed computing (like SETI) to handle processing the data from this thing? It would be very cool to get data blocks from such a state-of-the-art device. Granted, it isn't looking for little green men, but I'm sure they have a fair amount of data processing to handle.
"The universe seems neither benign nor hostile, merely indifferent." --Carl Sagan
Sen. Byrd, is a big muckity-muck in Washington [D.C.].
Please phone home!
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What exactly is a 'radio telescope' anyway?
TK
Well, I've got family ('kin') up in wva, and I even have a mountaineers t-shirt. It's nice to see something besides coal mines going up there. Maybe now I'll have a reason to go to the next family reunion.
YaY
-Space for rent
So if the first one lasted 16 more years then it was supposed to this one should last over 75 years. I think more places should underestimate the lastingness of their products.
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"...the telescope it replaces (designed to last 10 years) collapsed in 1988 after only 26 years."
It was designed to last 10 and only lasted 26? They must have skimped on the corner-cutting.
--
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I know its a different program, but why couldn't we spend this kind of cash on a supercollider?
How many telescopes do we need?
We need more particle accelerators, not telescopes. What difference does it make probing the universes' interior if you don't know how atoms work?
-Sleen
(Great, now I sound like my computer science teacher, babbling about obslecence being one of the most important portions of the great and holy System Design Life Cycle.)
Pretty cool, though. It's good to know that at least some of these science-for-the-sake-of-science projects are being built.
The telescope it replaces (designed to last 10 years) collapsed in 1988 after only 26 years
That looks like a mistake...
...because of the lack of, er, radio noise.
try { do() || do_not(); } catch (JediException err) { yoda(err); }
Personally I believe this will be a nice addition for people doing Sky Surveys... The more we can see, the more we will know and find out.
"We expect it to probe such mysteries as the birth of galaxies in the early universe, the birth of stars and the chemical composition of interstellar dust and gas. These are the very elements created in the universe that eventually become the stuff of biological systems."
This is an interesting quotation. What I'm curious about is how it is going to probe these mysteries about the birth of galaxies. Also, this person (Rita Colwell, the director of the National Science Foundation) seems to think that other biological systems will form, and this radio telescope will help unravel that mystery. Can anyone tell me how this telescope will do that?
mmm...physics...
When the original telescope at Green Bank was put up, they made an educational film about the task of bringing the large and heavy materials over the small roads and bridges. The movie either had a title of or was commonly referred to as something like "West Virginia's Big Erection" when it was shown to attendees of the National Youth Science Camp, which is located not too far from Green Bank. Here's hoping they updated the classic movie when they put the new one up!
-=-=-=-=-=-=-=-=-=-=-=-=-= John Reinert Nash -=-=-=-=-=-=-=-=-=-=-=-=-=
The telescope it replaces (designed to last 10 years) collapsed in 1988 after only 26 years
It lasted 2.6 times as long as expected and you're complaing?
Intel transfer the difficult from Hadware to software, for get more power, programmer need more technology. -- chinaitn
the bum around the corner picks up signals from deep space with his little aluminum foil hat! that couldn't have cost more than $0.20..
...dave
Think different? I'd be happy if most people would just think...
I thought that arrays of smaller radio telescopes are much more powerful than one giant one. And that is why they rarely make giant ones now-a-days... Can anyone back me up here?
-- "Almost everyone is an idiot. If you think I'm exaggerating, then you're one of them."
Good quote, too many chars. Seriously, the slashdot 120 char limit sucks!
With all these new telescopes were coming out with how come we cant use these to see pictures of like europa or pluto or something. I know they can, but the pictures are really bad / small / pixelated from what ive seen. I guess we have no chance of ever spotting another planet around another star if we cant even barely see our own! . So what im wondering is how much more will these telescopes have to be in order to get reasonably good resolution on our own planets. (and yes I realize that non stars are alot harder to see because the only light they give off is reflected.. but still.)
Isn't it cheaper to build a large array of smaller steerable dishes? Or do you get a better signal with just one big one? .gov project... that's only about $6000 a day.
And 75Mil does sound like a good deal for a
I clicked on that MS link wanting to be a good citizen and help stamp out MicroSoft in any way I can. Oh, *that* MS! :P
Obviously political arm twisting is why such a project ends up in West Va. (The New River Gorge Bridge was another example, which ultimately has paid off well for WV)
Question: Won't the RT's proximity to the east coast megalopolis suffer it interference problems: noise from jet traffic, radio, TV, etc.? I'm sure a certain amount of this can be filtered, but the less need for filtering the better, IMHO.
Vote Naked 2000
A feeling of having made the same mistake before: Deja Foobar
Isn't it sad that the telescope should be named for a senator (already famous) rather than a scientist?
Don't get me wrong -- I think it's better to have the telescope than not, even if you have to kiss a little senatorial hiney in order to get funding. Byrd was a respectable fellow. But it's a real commentary on the motives of America's politicians (who I think are underpaid and thus feel justified in seeking compensatory perks, like this one).
Sean
Let's see that's US$4.69/lbs.
More than decent steak but I guess that's not bad purchasing in a "This product is shipped by weight not by volume" kinda way....
=tkk
Bill Gates - Creationist?!?
I live in Charlottesville, so I know where I am going for an afternoon of fun.
Where am I going and why am I in this handbasket?
"The 100 meter Robert C. Byrd Green Bank Telescope (named after a West Virginia senator)"
has been nicknamed, "The Porkbarrel" out of respect for the free-spending representative and his spending practices since arriving in Congress.
Besides the 75million taxpayer dollars for the telescope, 44 million dollars in highway improvements were also added to the area. In addition, 22 million dollars was allocated with the project to maintain West Virginia's Fort Wayne, the only US Army post still servicing stage coaches and mule wagons for our nation's armed forces. Finally, a 14 million dollar grant was included with the telescope money for a new medical study into the benefits of leeches in medicine for the University of West Virginia.
Thousands of the Senator's supporters turned out for the festivities including government subsidy recipient Marla Thornhill of Buck Hill, WV. "My tobacco farm would have been closed down if it had not been for the generosity of Senator Byrd. Without those tobacco subsidies, I would have to quit growing the stuff and switch crops. Millions of Americans have to be thankful for Senator Byrd's committment to the family tobacco farm".
Senator Byrd was expected to arrive later today aboard an Air Force C141 cargo jet along with 40 of his staffers before leaving for a fact finding tour of Bermuda for the next week.
SETI!=SETI@HOME
GREEN BANK!=ARECIBO
Geesh!
This telescope isn't even for getting electromagenetic radiation, let alone part of the SETI clan.
RC5 will be cracked!
So what? I have a neural net somewhere on a 5 1/4"
SETI should return results!
That's what I'm talkin 'bout
http://siokaos.org/
Ok, it's OT, but it's still funny. Much better than all the LD commercials I have to suffer each day during my 1 hr (each way) commute.
...uh... hemisphere, weighing it at 180lbs in green black tights, with a license to kill, James Bond!"
...uh... hemisphere, weighing in at 220lbs, in pink Spandex, Ernst Blofeld!"
Maybe they'll show it off in a new James Bond movie...
"Let's get rrrrrready to rrrrruuummmble!"(tm)(C)
"In this
"And in the other
Vote Naked 2000
A feeling of having made the same mistake before: Deja Foobar
Before coming to Transmeta, I worked for NRAO for five years (1993-1998). Some of that time was spent working on part of a software project (AIPS++) related to this telescope.
Most people probably don't realize the immensity of the software challenge that handling the amount of data this telescope will produce is. It's not just a monster piece of hardware--it's going to produce simply tremendous amounts of data; the software aspects of this unique telescope will be as interesting as its hardware aspects.
I remember driving through West Virgina. In Virginia the highway I was on had only two-lanes. When you go into WV it went to four lanes. Then about twenty miles later or so it goes back to two-lanes driving into Maryland. There was virtualy no traffic on the highway anywhere. Just Sen. Byrd bringing home the bacon like no one else can.
Now we have a $75 million dollar radio telescope. Just what we need a radio telescopes when the gov't is already several trillion in debt. (And it will end up costing more than that. After all someone has to operate it and maintain it, just so some scientists can get their favorite station from alpha centauri)
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C) If yes, *BSD would have been a much better choice!
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The original telescope was built because construction of the 140 ft telescope fell behind schedule due to the complexity of the design. The 300 ft telescope was built in order to provide a working telescope quickly. It was designed and built quickly and cheaply. Probably the best investment ever made by a government in science. Since it was a transit telescope it moved every 20 minutes or so during it's lifetime. Basically it shook itself apart very slowly.
m l one of the supported systems is Linux.
Some stories I've heard:
1) When the telescope operator called his boss to tell him the telescope fell over, he was asked if he had been drinking.
2) During the process to line up funding for the replacement, the guy in charge of the NSF wanted to put a gravity wave thing there instead of a telescope. He was told Senator Byrd wanted a telescope.
Note: these are all second hand info. No warranty.
At any rate I have seen it and it is truly an impressive structure. It should produce some very impressive results as well.
Also look at the AIPS++ webpage at http://www.cv.nrao.edu/aips2/daily/docs/aips++.ht
Sounds like a weapon that is available in Quake!
Attention all planets of the Solar Federation! We have assumed control! - Neil Peart
In this case, the scientific community will probably benefit, but I do wonder what the opportunity cost is...
sulli
sulli
RTFJ.
If we could always tune in at night and see what scientist were seeing, it would be awsome. They could have a little caption about what was happening or something along those lines. I think it would be great to sit, watch, and know whats going on as they move around the sky...
From personal experience, I can heartily recommend it.
;-)
It's worth a trip out of your way to take the tour. It is a beautiful area, not far from where I was born, and the tour is really interesting. They take you by the telescope SETI rents, and they have a flag out if they're listening while you're there. Only diesel engines are allowed in the area, because traditional engines generate electronic interference. The area also forbids microwaves or other devices with lots of RF noise. Plus there are cool T-shirts, a must-have for any geek.
For those who don't know what Greenbank is, also the home of other telescopes...these include
- 140 foot radio telescope (closed last July)
- GBI (Green Bank Interferometer)...a set of 85-foot telescopes
- OVLBI...a huge satelite tracking station.
Greenbank is one of 9 (If I remember correctly) tracking stations able to conmmunicate with the Hubble Space Telescope and is going to be one of the 2 or 3 major tracking stations for Arise - the next generation of space telescope.
Around the area is a military enforced "Quiet Zone". It is true that Green Bank is located in the "backwoods" of WV, but this is the reason for its existance. Belive it or not, this location is right up there with Arecibo in its usefulness to the astronomical community (maybe more so).
Good tool for science, bad person to name it after.
stopping ACTIVE senators from having crap named after them? EVERYTHING that is new in that state has his name on it.... and it is all built with money he pork-barrelled for the state. Now if he wants to spend HIS money on it, I'm all for naming stuff after him. Now back to the topic... here is a picture I took on vacation over July 4th. Kind of anachronistic if you notice the G.O.B's (Good Ole Boys) to the right of the barn loading hay. http://www.lestersworld.co m/vacation/disk07/MVC-016X.JPG
A few years ago I worked as a summer intern in Green Bank, WV at the NRAO installation. At the time, all that existed of the new telescope was a huge flat concrete pad. This post might be off-topic, but maybe I can convey something of what it was like to work there (not that my memory is perfect):
* The town (really two towns - Arbovale as well) is very small - a few hundred people, many of them employeed by the observatory. Unlike many small towns in Appalachia, these two towns do well economically because of the government spending there. There aren't many other towns around - they intentionally put radio observatories in places where there isn't a lot of interference.
* To track what radio interference there is, they have this truck that looks like an ice cream truck that's got some really outlandish antennas on it. This weird guy with a beard and sunglasses would slowly drive up and down the roads looking for interference. I'm sure it really freaked out the locals.
* More interference: at least when I was there, there were no gasoline cars allowed on the observatory grounds because the spark plugs (or something) interfered with the telescopes. Instead, there were these old diesel taxis - Checkered Cabs that are probably still used only in Havana these days. You could sign one out and they would generate huge blue clouds of exhaust.
* There was no hunting allowed and so there were HERDS of deer. Really. I rode my bike past herds of maybe 50 deer in fields, just eating and looking completely relaxed. If only I had had a blunderbus! There were several such groups. It ruined me forever for the novelty of seeing a deer - whatever! I saw hundreds of them.
* Sometimes, they would put this weird attachment on the 140' telescope that would quickly move the receiver back and forth about twice a second (I have no idea what it was for). It would make this intense, slow, drumbeat sound that would echo down the valley...kachunk...kachunk...kachunk.
* It was an excellent place for mountain-biking. The local mountains were at most a thousand feet tall and were covered in old logging roads in various states of disrepair. You could take it easy or really get a workout. * The people at the observatory were very nice and professional. It was a wonderful experience for me (I was there for computer work, not astronomy), but at the time - early 90's - we only had a modem-speed connection to the outside world! Ouch! * Some of the control computers (at least when I was there - maybe they've been replaced since) there are REALLY old - 60's era stuff. It was just easier to keep the old stuff running than connect new machines to the telescopes. There were hard drives that looked like washing machines and even a punchcard reader (a backup, not in active use). The new telescope, that just went live today, however, was slated to have the latest and greatest computer equipment.
That's all the I remember...Thanks for the memories, Slashdot!
he area also forbids microwaves or other devices with lots of RF noise
No microwave?
How do they feed the resident geeks then?
So... why waste precious dinner / club / MustSeeTV / whatever time with a webcam when you could be "contributing to scientific research" from work? : )
(Besides, it'd be more "webwaveanalyzer" than webcam, wouldn't it?)
We're not seeing any alien transmissions because we're ignoring their TV and cell phone transmissions! DUH! Am I the only one that sees a problem with this? Imagine some alien civilization blocking out all our TV, cell phone, and radio stations.. what would be left to listen to!? DUH!
"This telescope will allow scientists on Earth to touch the stars without leaving the hills of West Virginia"
Wow, how profound. Too bad Galileo didn't say something like that when he first built a telescope. Just goes to show how the Senator has ABSOLUTELY NOTHING to do with this project.
"You'll die up there son, just like I did!" - Abe Simpson
There is no reasonable defense against an idiot with an agenda
:wq
As soon as the local teenage yokels find out it's a 100 *meter* telescope, I'll bet they fill it with bullet holes.
Marco...that was Portugese.
Reknowned physicist siokaos made the shocking announcement today that radio waves are not, as had been previously thought, part of the electromagnetic spectrum.
"Radio waves pushed the real electromagnetic spectrum out of the way years ago," he said, "they fooled Einstein and Maxwell, but not me!".
siokaos is not sure what happened to the "real" electromagnetic spectrum, but he is currently working on the theory that they evolved into fish.
--
--
E_NOSIG
A particle accelerator of the class that would actually be useful today would cost orders of magnitude more money than this telescope. Plus, I'd argue that there is always need for more telescopes -- getting time on any major scope is hard as hell (spoken like the bitter grad student I am), and there are a lot of things out there to look at. :-)
I've been there quite a few times, since I grew up in Morgantown, WVa. Greenbank is something surreal. You drive down the road, between these mountain ridges, and turn the bend, and right above the tree tops are these huge dishes. Just unreal, right out of Star Wars. They have bikes that are free to the visitors, since autos will distrube the radioscopes. You can walk up any of the scopes and look around, walk in and talk with the operators, etc. You'll see plenty of deer (watch out for deer ticks!), birds and other wild life, all which basically have run of the place. Take along a good camera, (a 18mm-36mm lens and a telephoto are suggested), and a sense of adventure. Also leave behind you cell phone, and other radio equipment, since it will not work there (radio free zone, don't want to go and goof up the science). I'll dig around and see if I can locate any pictures I have of the area while the dish was being built, it was totally mind blowing. Location wise, if you want to take a hike down to Greenbank, it's about 4 hours south of Morgantown, WV, 3 hours from Elkins, about 2 from Bluefield, and 3? from Charleston.
III.IIVIVIXIIVIVIIIVVIIIIXVIIIXIIIIIIIIVIIIIVVIII
My parents still live in West Virginia so I have been getting all sorts of neat articles related to this scientific wonder. Seems like yesterday when the old one fell down.
One of the reasons this thing is located in West Virginia is because of the location. It is surrounded by some very large mountains on all sides that shield it from radio interference.
Everybody in the surrounding area drives a diesel engine because anything with a spark plug generates a huge amount of radio waves that overwhelm the sensitive instruments.
I read an article about a woman in the town that had a short in her electric blanket that was driving the scientists nuts. It took them about a month to track down the source of radio wave interference.
My parents have taken the tour and they said the thing is impressive. Every time I see it, it reminds me of the shield generator that got blown up in Return of the Jedi.
- D -
Seriously, my family held a loosely organized family reunion up at Watoga State Park for most of July. (People came & went) Unfortunately, I wasn't able to be there when they went to go see the telescope, but my Dad brought back a t-shirt for me. He said the tour was a little dissapointing, owing to their guide being newly hired. There is also a presentation held where they show off a piece of software that lets you submit a request for an "image" of a portion of the sky, and later help analyze it when it gets to you.
It really sounds interesting and I hate to think I missed it. But I also missed most of the deer sightings and the bears that came nosing around the cabin one morning.
dana
and all good hillbillies know that the satellite dish is the state tree.
"..don't you eat that yellow snow."
This post brings me to my most interesting
feature request from slashdot.
Remember all the questions you asked when you
were eight years old ? ever heard any answers ?
Like what really is a radio telescope (answered
excellently at the beginning of the comments) ?
how does a photosensor work ? what *is*
bandwidth (i mean, is a property of wire? or is
it something to do with material? or what?)
or linguistics.
Even some excellent newbie tech questions. Like
TCP/IP stack or ray tracing or PCMCIA or
filesystems.
I am sure there are people out there who can
contribute a lot of good features to us by writing
up small features on a lot these kinds of
questions.
These features and the ensuing technical discussion, IMHO, will be far more interesting
than the licensing issues which are talked about
way too often.
Here's the nice, fluffy page. Somewhere near the bridge is a nice little museum, put up by the visitors bureau, which details the critical view of it as a pork-barrel project, as there was little traffic around the sleepy little town of Fayetteville prior to construction. Main benefit was expected to be for trucking, IIRC. However, the bridge can easily be defended now as it has brought whitewater rafters, bungee jumpers, hikers and much other recreational use revenues to the area. (Worth a few trips, to be sure.)
My bone of contention over the choice of WV for the Green Bank Radio Telescope is there are obviously much better locations, particularly in the west and at higher elevations.
But who knows, they may make tourist dollars, yet off this thing. Maybe there'll be a bungee jumping day...
Vote Naked 2000
A feeling of having made the same mistake before: Deja Foobar
Some of the other people here have already answered the basic question: a radio telescope acts much like an optical telescope, except it uses radio waves which then get converted into images by computer. Why use radio waves? For one thing, you can pick up emissions from warm interstellar gas that isn't hot enough to actually glow visibly; some of the basic ionization effects in the universe occur at specific microwave frequencies; and radio doesn't get as distorted as much as light does when passing through the atmosphere.
The real fun part comes when you start hooking multiple radio telescopes together to perform VLBI: Very Long Baseline Interferometry. By viewing the same object from multiple locations, you can pick up details that either telescope by itself would have missed. The more radio telescopes you have, and the further apart they are, the better resolution you can get on the final image.
For really long baselines, the Japanese launched a radio telescope up into orbit a few years back. By itself it's not all that good; radio telescopes don't get as much of a boost from being outside of the atmosphere. But combine that with telescopes on the ground at the same time, and the combined system has a resolution over a hundred times better than the Hubble. People have actually managed to pick up details from quasars that nobody had been able to see until recently.
Of course, you can also reverse VLBI: once you have a quasar or some other highly distant object mapped out, you can invert the calculations and determine the exact relative locations of the telescopes from a new observation. This means, for example, you can determine if two telescopes have moved further apart since the last time you looked at this quasar: you can track continental drift. Or the rotational period of the Earth to sub-millisecond precision. Or there's been talk of using radio telescopes and VLBI to help correct for phase drift errors in GPS satellites.
Not to mention some of the other work on tracking space debris and meteors by using radio telescopes...
-- Bryan Feir
I had an opportunity to visit the Green Bank complex a couple of years ago, and loved it. For your inner Mech. Eng., there's some really, really big, impressive structures. For your inner physicist or astronomer, there's a pretty damn good museum with lots of astrophysical trivia for amusement. And for your inner child, there's a periodic (live!) presentation in the museum auditorium, complete with a dewar of LN2 that they use to freeze balloons, drive a nail with a banana, and (finally, the best part) scare the little ones by tossing it on the floor right in front of them.
Seriously, it was a lot of fun. Even the 5-year-old enjoyed it.
the largest non-steerable radio telescope remains Arecibo at 1000 feet diameter.
There's a West Virgina senator named Green Bank?
Why such a large dish? I am not a radio astronomer, so I am sure there is a good reason. I understand that it is a large parbolic reflector, and of course the bigger it is, the more it can gather. I also like the idea of the single arm mount (damn that thing is HUGE!)...
Why did they choose to build it this way, instead of a large array (such as done in NM)? Is it because errors or other anomalies are introduced into the data when the individual data streams are "combined" in an array - that might mask something or another?
Please, someone - enlighten me!
I support the EFF - do you?
Reason is the Path to God - Anon
There are some cool pictures of the 300ft one that collapsed here
Not only is it a beautiful drive to get there(radio telescopes are located in the boonies for a reason) but the actual experience of coming suddenly into a valley covered with these instruments is pretty awesome in and of itself. The tour of the facility is interesting (you have to take a diesel bus---spark plugs do bad things to radio telescope reception) and the "experience of science in action" permeates the place. If you live anywhere within a day's drive of Green Bank, I'd highly recommend planning a trip. You will remember it for a long time.
Dude, when was the last time you saw a "very large mountain" anywhere east of the Mississippi? ;-)
My only drive through WV took me over some very large hills! (and I do recall one trip through a pretty large tunnel, I think that was in WV). I suppose they are big enough, from what I've read here, to do a good job of shielding radio interference. Just how big are they, I wonder? Guess I can check out a map.
Anyway, I have views of 10,000+ foot mountains outside my window here, and could not resist jabbing at easterners' definition of "mountains." :-) Now, if only we had a Robert Byrd here in Oregon... we could use a little pork here.
It appears to me that Green Bank is just a standard offset feed design. This is the same design used in your dinky DBS TV dish and virtually every small satellite antenna in the world. That said, there certainly are other things that distinguish Green Bank, including the colossal size (and [oink] price) and the dynamically adjustable surface.
One of my work colleagues once provided me with the following explanation to help understand how these offsets works.
Visualize a standard "prime focus" antenna. This is the kind that has the struts from the edge of the big reflector to a point in the air above the exact center of the dish. Energy from space hits the metal reflector and is bounced towards the focus point, where the struts meet and your receivers are. Here's a PDF of a prime focus antenna.
Now imagine that the antenna is pointed straight up, so it's like a bowl catching rain. If you sliced vertically through it, you'd see a perfect parabola, which would go further out and up if you extended the curves of the reflector. The receiver is sitting at the focus point of that parabola.
Imagine that perfect, mathematical parabola sitting there, with the sides extending out and up. The reflector just happen to be a metal realization of the very bottom of that parabola. We could make antennas where the reflector extends furhter up the sides of that mathematical parabola, but eventually it's just lots of expensive metal structure for not much gain (pun intended :)).
Here's the cool part: Now imagine that instead of the metal reflector occupying the bottom of the parabola, you slide the metal "skin" UP THE SIDE of the mathematical parabola that you're envisioning. The parabola doesn't move, and thus neither does the focus point. Just slide the metal "realization" of that paraboloid curve up one side.
The antenna is still "looking" straight up into space, but now the reflector is off to the side a bit. The reflector on your DBS dish is actually a mathematically very complex section of a 3D paraboloid surface. But it's usually hard to tell because the reflector is relatively flat, and thus it's hard ot detect the complex curves involved. Here's a bunch of pictures of offset-feed dishes.
Green Bank has the feed overhead, unlike your DBS dish. It's still the same idea; they just spun the whole thing around on the line-of-sight axis.
What's the big advantage? As the article hinted, you don't have those struts in the way of the incoming energy, and thus the antenna is more efficient. Also, on a big system like GB, it's possible for them to lower the feed/receiver assembly closer to the ground where it's easier to service.
In my job, we usually have the antennas oriented like your DBS dish, with the feed close to the ground. But when you get to real high latitudes (like in Alaska or Siberia), the satellite you're trying to hit is real close to the horizon, and when we try to aim that low, the feed hits the ground. In those rare cases, we have to spin it around to put the feed high up in the air, like GB, only WAY smaller.
By the way, there's a kind of antenna (called a Cassegrain) that looks sort of like a prime focus, but has a second refector at the feed which bounces the energy back down to the receiver at the center of the main reflector. Here's a PDF of a Cassegrain antenna.
PDFs courtesy of my employer :)
One simple rule for its versus it's
what is with the WV bashing going on here? i happen to be from WV, and am proud to say so. also, someone always mentions Sen. Byrd when it comes to big government project, and it is always in a negative manner. yes he does bring in big money projects to this state, and yes, sometimes they are questionable, i.e. the Cost Guard thing, but he is doing his job. he is supposed to protect the interests of his state, and if that means trying to bring in big money projects like the GBT, then so be it. that is why he keeps getting voted into office.
"One man's "magic" is another man's engineering."-- Robert A. Heinlein