Time is on South Africa's side” in its bid to host the giant Square Kilometre Array (SKA) telescope project that is expected to cost over one billion Euros, writes Shaun Benton.

So says the nation’s leading astronomer, Professor Phil Charles maintaining that South Africa has time because the technology needed to cater to data rates and computer processing for the SKA project to do “all the science” that the project's leaders are aiming to do, does not yet exist.

Speaking to BuaNews, Professor Charles, the director of the South African Astronomical Observatory, said the reason for this is that the combination of the spatial resolution and temporal resolution required from the SKA telescope is not yet available on world markets.

Thus, to complete the SKA at this stage would be impossible, says Professor Charles, because the bandwidth, computer processing power and data storage required do not yet exist – anywhere.

However, the professor believes that the required technology would be available between perhaps five to eight years.

He has calculated this on the basis of what is known as Moore's Law, the theory arising from the rate of current technological innovation that assumes that raw processing power and hard disk capacity will double every two years.

In the meantime, however, South Africa, needs large investments in bandwidth capacity to bridge the digital divide and specifically for a high-speed academic Internet backbone.

Plans are in the pipeline for an African equivalent of the European Geant2 network, which currently provides an academic backbone through Europe of 10 gigabits per second. This is at least 1 000 times faster than that currently available in South Africa.

Already SALT – the Southern African Large Telescope that was inaugurated by President Thabo Mbeki in November 2005 – is working around limitations in data transmission by using its 1.5-million-bits-per-second dedicated data line between Sutherland, where SALT is located, and Cape Town.

This “uncalibrated” data is then reduced through processing to a point where SALT's partnership scientists can access it over the Internet from the United States, Europe and elsewhere.

However, better bandwidth is needed, argues the professor. Without it, the “pathfinder” radio telescopes array's being constructed by South Africa (and Australia) in preparation for the SKA, would be limited.

From the initial suite of four regions of the world that expressed interest in hosting the planned Square Kilometre Array telescope, which will be the most powerful radio telescope on Earth, South Africa and Australia have been short-listed as potential hosts.

This is because the technical committee examining the four sites – in South America (in particular the region around Argentina and Brazil), as well as China, southern Africa and Australia – found that the ionospheric background in the Earth's atmosphere was less apparent in the southern hemisphere.

Professor Charles explains that the ionospheric background in the earth's atmosphere – the upper part of the earth's atmosphere that is affected by radiation from the sun to the point where it impacts on the propagation of radio signals – is not uniform over the whole planet.

“The quietest parts [of the earth's atmosphere] are actually southern Africa and Australia,” says Professor Charles.

“You can see this background during the day and there are times when it just sort of flows from south America up across north Africa and across China and during the most sensitive observations that would limit the sensitivity of the [proposed SKA] telescope,” he says.

As a result, about 15 months ago the technical committee dropped the South American and China regions, leaving the race for the world's most powerful telescope – which would 100 times more sensitive than current instrument - open to southern Africa and Australia.

The southern hemisphere already has more large telescopes than the northern hemisphere because of its competitive edge over the north, in part because the galactic centre goes directly overhead in the southern hemisphere, giving astronomers in the south “the best view of the centre of our own galaxy”, says Professor Charles.

In the south, South Africa has a further competitive edge because world-class research requires access to dark, clear skies at regions preferably above 1 500 metres above sea level, and for this, only Chile and South Africa qualify because of the lower altitudes of Australian optical observatories.

Already, Chile is home to the European Southern Observatory, which has four eight-metre telescopes situated in the country.

South Africa was favoured for the SALT telescope, which is situated in a quiet part of the Karoo – Sutherland – that is largely free from human interference in the form of night lights, television signals, cellphone signals, etc, all of which cause radio interference.

South Africa recently moved to strengthen this “astronomy geographic advantage” with the passing by parliament last year of the Astronomy Geographic Advantage Bill that seeks to preserve and protect areas within South Africa that are uniquely suited to optical and radio astronomy. This was done in order to preserve the country's competitive edge.

In the meantime, work goes on at the South African Astronomical Observatory in Observatory, Cape Town, and in Sutherland, while work has begun on the SKA “demo model”, the world-class Meerkat telescope whose 12-metre dishes will be spaced over 10 kilometres in the Karoo.

And should South Africa win the SKA bid, there will be antennae scattered all over the southern African region, with the main site in the northern Cape. It will have an effective collecting area of a million square metres, Professor Charles said last year in the South African science magazine Quest.

As such, it will have an effective data collecting area of million square metres, making it the most powerful radio telescope on Earth.

South Africa needs the project, says Professor Charles, and not just for studying the skies.

“Astronomy is a fantastic way of inspiring young people into science,” he says, and is also “one of the most superb ways of actually teaching people basic physics and mathematics.”

The country, he says, “desperately needs a scientifically, technically literate workforce if it is truly going to make the transformation that we hope for”.

Then, generations of South African children could choose to enter a variety of scientific fields, or simply stay put in astronomy and spend time considering such weighty matters as pulsar timing and how, when it changes in different directions, “you can actually detect gravitational waves that are propagating through the universe ...” - BuaNews