When Lofar Meets Stella 123
Roland Piquepaille writes "The LOFAR (Low Frequency Array) telescope is a new IT radio-telescope which will use about 20,000 simple radio antennae when it's completed in 2008. At this time, it will cover an area with a diameter of 360 kilometers centered over the Netherlands. Its small radio antennae will detect radio wavelengths up to 30 meters, and because the ionosphere can bend some of these radio waves, the Lofar images might be somewhat blurry. So all the information captured by these antennae will be digitized and sent to a computing facility at a rate of 22 terabits/second today, and almost 50 terabits/second in 2010. This is the reason why Lofar needs Stella, an IBM supercomputer installed recently in Groningen, also in the Netherlands, to process signals from up to 13 billion light years from Earth. Stella consists of 12,000 PowerPC microprocessors and has a computing power of 27.4 teraflops. This overview contains more details and a picture about the Lofar-Stella interaction."
From Piqy's stupid Blogvertisement (Score:5, Informative)
When Lofar Meets Stella
The LOFAR (Low Frequency Array) telescope is a new IT radio-telescope which will use about 20,000 simple radio antennae when it's completed in 2008. At this time, it will cover an area with a diameter of 360 kilometers centered over the Netherlands. Its small radio antennae will detect radio wavelengths up to 30 meters, and because the ionosphere can bend some of these radio waves, the Lofar images might be somewhat blurry. So all the information captured by these antennae will be digitized and sent to a computing facility at a rate of 22 terabits/second today, and almost 50 terabits/second in 2010. This is the reason why Lofar needs Stella, an IBM supercomputer installed recently in Groningen, also in the Netherlands, to process signals from up to 13 billion light years from Earth. Stella consists of 12,000 PowerPC microprocessors and has a computing power of 27.4 teraflops. Read more...
Let's start with the opening paragraphs of an article from New Scientist, "Huge radio telescope boasts supercomputer brain."
One of the world's most powerful supercomputers is to be the brain of a revolutionary new radio telescope called LOFAR. The telescope will look back to the time of the very first stars, map our galaxy's magnetic field and perhaps discover the mysterious sources of high-energy cosmic rays.
Instead of one large rigid dish, LOFAR will use thousands of simple radio antennae. Their signals will be woven together at the University of Groningen in the Netherlands by STELLA, the new supercomputer, which was launched on Tuesday and is unofficially ranked as the third most powerful on the planet.
LOFAR needs its own supercomputer because it aims to detect radio wavelengths of up to 30 metres. Such long-wave radio images are blurry, and the only way to make them sharper is to build a vast array of detectors spread over hundreds of kilometres.
Now, let's move to the General Information section of the LOFAR website for more specific information.
LOFAR is the first telescope of this new sort, using an array of simple omni-directional antennas instead of mechanical signal processing with a dish antenna. The electronic signals from the antennas are digitised, transported to a central digital processor, and combined in software to emulate a conventional antenna. The cost is dominated by the cost of electronics and will follow Moore's law, becoming cheaper with time and allowing increasingly large telescopes to be built.
So LOFAR is an IT-telescope. The antennas are simple enough but there are a lot of them - 25000 in the full LOFAR design. To make radio pictures of the sky with adequate sharpness, these antennas are to be arranged in clusters that are spread out over an area of ultimately 350 km in diameter. (In phase 1 that is currently funded 15000 antenna's and maximum baselines of 100 km will be built).
Below is a general diagram of the LOFAR-STELLA interaction picked from the System section of the LOFAR website (Credit: LOFAR).
A diagram of the LOFAR environment
Details are scarce about the STELLA supercomputer, built by IBM using some of its Blue Gene/L technology. Reuters gave some information last week in "Europe's Biggest Supercomputer Eavesdrops on Stars."
Running on 12,000 PowerPC microprocessors, the computer can execute 27.4 Teraflops, or 27.4 trillion floating-point operations, per second.
The new computer will consume 150 Kilowatts of power -- the equivalent of 2,500 60-watt light bulbs -- which is considered economical for a supercomputer, IBM said.
If you understand Dutch, you also can read this news release about this supercomputer.
Now we have to wait to see if the happy couple of Lofar and Stella can produce images as beautiful as Hubble gave us during the last decade.
Sources: Various websites
Stella and Blue Gene (Score:2, Informative)
Details are plenty since what IBM gave to the project is a couple of racks of BlueGene so everything applies, scaled proportionately.
Here are some details: http://www.research.ibm.com/bluegene/ [ibm.com] and http://www.llnl.gov/asci/platforms/bluegenel/ [llnl.gov]
IBM BlueGene (Score:5, Informative)
You cross-compile your application on a power4/5 linux box, and then submit it to the system.. they reduced the computational aspect to it's most basic components.. CPU/FPU, memory, and MPI interconnect..
compute nodes don't even have ethernet or drive controlers... all I/O is handled by another specialized I/O node, which provides data over one of the two MPI interconnects.
aperture synthesis array (Score:4, Informative)
It's a big mess-O-sensors spread over a wide area.
Radio, seismic, atmospheric pressure, and "other".
With the big iron computer it will be possible to play around with all sorts of spatio-temporal signal processing. This has been done with optical telescopes to remove 'twinkles', SA-RADAR and SA-SONAR, and most intensively in oil exploration where 2-D arrays of seismic sensors coupled with 2-D arrays of seismic sources are used in oil exploration. The neat thing, just liek in oil exploration, is that the data from the different sensors can be looked at for correlations. air-pressure, seismic, and radio data all recorded around a significant geophysical event. Yes, I knwo this is 'fishing science', bu tit is fun...
Re:When Roland meets Slashdot... (Score:3, Informative)
Oh, and more ads, which make the purpose of Roland submissions appear to be simply to divert readers to his site on the way to the REAL news, just for those ad dollars.
Re:What they don't talk about.... (Score:4, Informative)