ska project
DESCRIPTION
Focus On The StarsTRANSCRIPT
WRITTEN BY JACK SLATER
What we see in the sky at night is nothing short of messages from the beginning of time as the light from the very nearest galaxy to our own left it before our human species even evolved. To achieve a deeper sense of enlightenment we need to uncover and study the nature of the universe to better understand ourselves first. We spoke with Managing Director, Dr. Bernie Fanaroff.
MeerKAT is cutting-edge and the
project is creating opportunities
for a large group of young
scientists and engineers with
world-class expertise in the
technologies which they did not
have previously. This will prove
to be crucial in the next 10 – 20
years in the development of
super-computing which will have
an impact on data transport,
the creation of large sensory
networks, radio software and
imaging algorithms.
“MeerKAT will be the most
sensitive radio telescope in the
southern hemisphere until SKA
comes online,” Bernie is quick to
point out, “It is by this credit that
leading radio astronomy teams
“South Africa has
already demonstrated
its excellent science
and engineering skills
by designing and
starting to build the
MeerKAT telescope
as a pathfinder to the
SKA”
SKA PROJECT
In South Africa, astronomers want to build the most powerful telescope ever, to see back to before the first stars and galaxies formed into the very source of all that is.
“The Square Kilometre Array (SKA) will be a radio
telescope,” explains Bernie, “Instead of seeing light
waves, it will create images via radio waves.”
This is a landmark occasion as the majority of the SKA - the full
dish array and the dense aperture array - will be built in Africa. The
core - i.e. the region with the highest concentration of receivers - will
be constructed in the Northern Cape Province, about 80 km from
the town of Carnarvon which is incidentally the same site where the
MeerKAT is being constructed. The sparse aperture array which is
the low frequency array will be put together in Western Australia.
“South Africa has already demonstrated its excellent science and
engineering skills by designing and starting to build the MeerKAT
telescope as a pathfinder to the SKA,” Bernie reveals, “The first seven
dishes, KAT-7, are complete and have already produced its first
pictures it has created a bit of a media storm and we’ve attracted
great interest internationally.”
In fact more than 500 international astronomers and 58 from
Africa have submitted proposals to do science with MeerKAT once
it is complete.
One of the reasons is that the technology being developed for
Endeavour Magazine | 35
around the globe have already signed up to use the instrument as
soon as it is ready.”
The concrete for the first MeerKAT antenna foundation was
poured on Wednesday 14 August 2013 at South Africa’s SKA site
in the Karoo. This is the first of 64 similar foundations that will be
constructed for this telescope over the next nine months with each
foundation consisting of 78 m³ concrete and nine tons of steel.
“Designing a foundation for a high-tech telescope is complex and
challenging since it has to meet a set of stringent requirements,” Tracy
Cheetham, general manager for infrastructure and site operations at
SKA South Africa explains. “The foundations must ensure that each
of the 19-m high antennas with its 13.5 x 16 m main reflector will be
exceptionally stable and able to point accurately at distant celestial
objects at wind speeds gusting to 69 km/h as well as survive wind
speeds of up to 144 km/h. Another challenge for the design team was
to ensure that each antenna was carefully earthed and would not be
damaged in the event of a lightning strike.”
In order to meet these stability requirements, each foundation
consists of eight steel-reinforced concrete piles at depths of between
5 to 10 m, depending on the local soil conditions. A square slab of
concrete over five meters wide and over one meter thick rests on
top of the piles to add further
stability. Upon that thirty two
“holding down” bolts are pre-
assembled in a circle to form a
steel ring cage, which is called
an engineering “bird’s nest”, into
which the concrete is then cast.
“This first foundation will
now be verified through a series
of load tests to ensure that all
specifications have been met,”
Cheetham says. “Getting this
absolutely right is critically
important for the science to be
done with this instrument, and
will also inform the construction
of foundations for other SKA
dishes to be built in the Karoo.”
Since 2005, the African SKA
Human Capital Development
Programme has awarded close to
400 grants (2012) for studies in
astronomy and engineering from
undergraduate to post-doctoral
level, while also investing
in training programmes for
technicians. Astronomy courses
are being taught as a result of
the SKA Africa project in Kenya,
Mozambique, Madagascar and
Mauritius (which has had a
radio telescope for many years)
and are soon to start in other
countries.
MeerKATThe MeerKAT array,
currently taking shape in South
Africa’s Karoo region, is a world-
class radio telescope designed
to do ground-breaking science.
It will be the largest and most
SKA PROJECT
sensitive radio telescope in the southern hemisphere until the Square
Kilometre Array (SKA) is completed around 2024. Via MeerKAT, South
Africa is playing a key role in design and technology developments for
the SKA.
Close to 100 young scientists and engineers are working on the
MeerKAT project. Based at the engineering office in Cape Town, and
at universities and technology companies across South Africa and
Africa, these researchers interact closely with SKA teams around the
world. In collaboration with South African industry and universities,
and collaborating with global institutions, the South African team has
developed technologies and systems for the MeerKAT telescope,
including innovative composite telescope dishes and cutting-edge
signal processing hardware and algorithms.
Prof Justin Jonas, Associate Director: Science and Engineering at
SKA South Africa, is very excited about the implications of the SKA
site decision for the role that South Africa’s MeerKAT telescope will
play in the future of the SKA. “The decision recognises MeerKAT as
a key instrument that will make up one quarter of SKA Phase 1 mid-
frequency array, and the science planned for SKA Phase 1 is very
similar to the MeerKAT science case - just much more ambitious,”
he explains. “Our researchers and students who participate in the
MeerKAT surveys have a huge advantage. They are well placed to
enter SKA Phase 1. They have the opportunity to become science
leaders in future SKA projects.”
Up to 2016 South Africa will be constructing the 64 MeerKAT
dishes in the Karoo and construction on 190 SKA Phase 1 dishes
should start more or less when MeerKAT is complete. “The design
of the SKA dishes is not yet final, but they should look similar to
the Gregorian-offset dish design chosen for MeerKAT,” Prof Jonas
expects.
KAT-7 (seven-dish MeerKAT precursor array)
The seven-dish MeerKAT precursor array, KAT-7, is the world’s
first radio telescope array consisting of composite antenna structures.
South Africa is currently building the Karoo Array Telescope, or
MeerKAT, a mid-frequency ‘pathfinder’ or demonstrator radio
telescope, alongside the SKA core site.
The first seven dishes of the local precursor instrument - known
as KAT-7 - were completed by December 2010 and are now being
commissioned.
It is the world’s first radio telescope with dishes made of fibre
glass. KAT-7 is an engineering prototype for the 64-dish MeerKAT,
but the world’s scientists see it as a useful instrument in its own right,
and they are keen to switch it on for doing science as soon as possible.
“KAT-7 has already delivered images of the Centaurus A, a galaxy
14-million light years away,” Bernie concludes.
“Designing a foundation for a high-tech telescope is complex and challenging since it has to meet a set of stringent requirements,” Tracy Cheetham, general manager for infrastructure and site operations at SKA South Africa explains. “The foundations must ensure that each of the 19-m high antennas with its 13.5 x 16 m main reflector will be exceptionally stable and able to point accurately at distant celestial objects at wind speeds gusting to 69 km/h as well as survive wind speeds of up to 144 km/h. Another challenge for the design team was to ensure that each antenna was carefully earthed and would not be damaged in the event of a lightning strike.”
32 | Endeavour Magazine
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