From Hartebeesthoek to Stellenbosch, from Grahamstown to Carnarvon, South
Africa’s Square Kilometre Array team are very busy behind the scenes,
designing, engineering and building the world’s largest and most advanced space
camera. That’s what the SKA is –
thousands of small antennas surveying the sky like a giant eye, but at the
incredible resolutions typical of radio astronomy and also more than ten
thousand times faster than previously possible.
But the images are far more detailed than a mere camera image, and as a
result, the data used to build these images has to be received, conveyed,
processed and stored. What’s exciting is
that the drive to build these new technologies will eventually have
applications downstream – to the man in the street. When you use Bluetooth on your phone or
laptop, or pick up the remote control to change a channel – you’re using legacy
technology courtesy of radio astronomy.
The SKA means much more is in store.
Prof
David Davidson from Stellenbosch University: "The main job of
the Stellenbosch research chair is to produce highly-trained engineers on
mission-critical electronic engineering technologies for MeerKAT and SKA. This
includes: the simulation and design of the dish; feed and receivers; signal
processing; calibration; and radio frequency interference mitigation. Many of
these graduates are already making a difference in industry."
Isak
Theron, Technical Director at EMSS: “We design the receivers, cryostats and feed horns (the small antennas at
the focus of the dish). We are… [also] involved in specifying the shape of
the reflecting surfaces.”
An interesting recent development comes from IBM: they have signed a 4
year deal to collaborate with the SKA in researching
extremely fast, but low-power exascale computer systems. A Dutch Institute for Radio Astronomy,
Astron will also be involved. The global reach of the SKA is impressive. Though the centrepiece of the array is at a
site about 85 kilometres from Carnarvon in the Northern Cape, the SKA itself is
headquartered in Manchester, England, and has around a dozen members, with
Germany one of the most recent. South Africa and to a lesser extent Australia,
are both involved in providing the actual radio quiet sites essential for radio
astronomy.
One of the most surprising aspects of the SKA are the
processing speeds required. Rendering
so much data is of course akin to rocket science. For images with
resolutions 50 times greater than produced before, data will have to flow
incredibly fast. But the volumes of data
are so massive that local and international technicians are still hard at work
trying to build them. 
The ROACH 2 is
part of the SKA’s answer to the processing power needed, and the CSIR’s Centre
for High Performance Computing (a vault of water-cooled 2 metre tall
processors) tucked in sleepy Rosebank, Cape Town, is performing an important
role in prototyping the SKA’s computer hardware infrastructure.
Carnarvon is already showing the benefits of all this
activity – a bevy of guesthouses and eateries have sprung up, including De
Meerkat, a wonderful new restaurant.
On the site itself in the Northern Cape,
massive construction is underway, including 64 circular platforms for the
MeerKat array ( a total of 3000 dishes will be operational eventually, around
the world), roads, and an underground bunker where signals will be processed.
Signal processors will be buried 5 metres below ground, and shielded by a massive
mound of sand around the facility, besides the shielding provided by the ring
of mountains that guards the area.
In December this year the first of the new array of 64
antennas will be erected.The total project cost is estimated at €1.5 billion.
Scary Facts About the SKA:
The SKA central computer
will have the processing power of about one hundred million PCs.
The dishes of the SKA will
produce 10 times the global internet traffic.
The SKA will generate
enough raw data to fill 15 million 64 GB iPods every day!
The SKA supercomputer will perform 1018 operations per second
– equivalent to the number of stars in three million Milky Way galaxies – in
order to process all the data that the SKA will produce.
The SKA will contain thousands of
antennas with a combined collecting area of about one square kilometre (that’s
1 000 000 square metres!).
More: http://www.skatelescope.org
The SKA project
timeline
2013-15
Detailed design and pre-construction phase
Detailed design and pre-construction phase
2016-19
Phase 1 construction
Phase 1 construction
2018-23
Phase 2 construction
Phase 2 construction
2020
Full science operations with Phase 1
Full science operations with Phase 1
2024
Full science operations with Phase 2
Full science operations with Phase 2
More: www.ska.ac.za
What
is Interferometry ? How does the SKA work?
An interferometer’s main
purpose is to increase the resolution of images using aperture synthesis. By overlaying waves, those that reinforce one
another (or are similar) are enhanced, whilst those of opposite phases cancel
one another out. The result is a much
sharper image, and beyond the image itself is plenty of information beyond the
visual, such as heat energy signatures, radiation, dark matter elements such as
time, movement and gravity that can be measured. An array amounts to a combined
telescope that approximates a single telescope, but is simply super-sensitive
in what it can see.The baseline determines the resolution, and some systems
span continents – which are known as VLBI or Very long Baseline Interferometry.
READ MORE: Once upon a starry night: The story (so far) of the Square Kilometre Array
READ MORE: Once upon a starry night: The story (so far) of the Square Kilometre Array
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