Old dish gives Ghana a new taste of the African sky
African countries turn to radio astronomy as a way to develop high-technology skills and attract scientists
The small observatory building smells of fresh paint and above it tower four storeys of hulking white metal. Its receiving dish 32m across, this telescope is the centrepiece of the Ghana Radio Astronomy Observatory.
The instrument, about an hour’s drive from Accra, will soon connect up with telescopes around the world.
African countries, with no small amount of urging from SA, have turned to radio astronomy as a way to develop high-technology skills and attract scientists.
Ghana’s dish was once used for telecommunications, but spent years collecting rust and birds’ nests. The laying of undersea cables down Africa’s coasts rendered such dishes, once a key communications tool, redundant.
But the late Mike Gaylard, a South African radio astronomer, had an idea: what if the obsolete dishes could be converted into a network of radio telescopes that spanned the continent? Thus the concept of the African VLBI Network was born.
VLBI — very long-baseline interferometry — is a type of astronomy that involves connecting telescopes in different places and making them act as one big telescope. Gaylard, who used to lead SA’s Hartebeeshoek Radio Astronomy Observatory, spent months scouring the continent with Google Maps, searching for redundant telecommunications dishes.
The Kuntunse dish outside Accra is the first of a number of planned conversions, heralding a new era in African astronomy and skills development.
"Big science infrastructure projects attract scientific talent," Science and Technology Minister Naledi Pandor said in Accra in August ahead of the launch. "Initiatives such as this bring our talent back home. They promote brain gain."
While Ghana’s telescope will be owned and operated by that country, the project has been driven by SA, which bankrolled the conversion with a R122m allocation from the Department of International Relations and Co-operation’s African Renaissance and International Co-operation Fund.
Part of the rationale behind this is to develop skills ahead of the construction of the Square Kilometre Array (SKA) telescope. The SKA, when built, will be the largest radio telescope in the world.
It aims to investigate some of science’s most perplexing questions, such as: what happened just after the Big Bang? What is dark matter? How do galaxies form? Are we alone in the universe?
In 2012, SA and Australia were selected as the primary hosts of the SKA, which will comprise hundreds of dishes and thousands of antennae.
During the first phase of the SKA dishes and antennae will be deployed in those countries, but phase two — tentatively pencilled in for the mid-2020s — will include eight African partner countries.
Botswana, Ghana, Kenya, Madagascar, Mauritius, Mozambique, Namibia and Zambia will each have a handful of dishes. However, these countries have limited radio astronomy expertise and engineering skills.
"One of the big things we found is that young people [in African countries] do not have the privilege of fiddling in laboratories," says Anita Loots, the associate director of special projects for SKA SA.
"We have brilliant mathematicians, nuclear physicists, engineers. They have an excellent theoretical background, but have never seen a soldering iron."
The telescope at the Ghana Radio Astronomy Observatory will not be part of the SKA, but it will be an important training ground for young scientists and engineers, she says.
Since 2005, SA has been driving education in radio astronomy-related disciplines in preparation for its SKA bid, with SKA SA awarding bursaries to almost 800 students. Several of these students have been Ghanaian, but in the past, they had no telescope to go home to.
SA has trained about 60 young scientists in astronomy and astrophysics, says Dickson Adomako, the director of the Ghana Space Science and Technology Institute. The observatory is part of the institute.
But in the past, "there [was] nothing for them to do when they get back to Ghana. We are trying to push hard for public universities to have these [radio astronomy] curricula in their programmes".
Bernard Duah Asabere, the manager of the Ghanaian observatory and a senior astronomer, says: "If you train one astronomer, you train a mathematician, an astronomer, a computer scientist and an engineer [in one]."
Ghana-born Asabere, who trained in SA, is Ghana’s first radio astronomer working in the country. For many years, Hartebeeshoek Radio Astronomy Observatory, about an hour outside Pretoria, was the only African telescope linked to Europe’s VLBI network of radio telescopes.
While there are almost two dozen old telecommunications dishes in Africa that could be converted into telescopes, SA is focusing its attention on SKA partner countries
But the more telescopes there are in a VLBI network, the more detail astronomers can see, and Ghana will fill a gap in the global VLBI network.
"Because of our position [in Ghana], we can see the northern and southern hemispheres," says Asabere. "We can tell the world things they do not know."
The telescope has already seen "first light", which means that it has made scientific observations. It has observed methanol masers — radio emissions that can arise from a number of celestial phenomena — and pulsars, which are stars that produce strong beams of radio emissions.
While there are almost two dozen old telecommunications dishes in Africa that could be converted into telescopes, SA is focusing its attention on SKA partner countries. Those with old telecommunications dishes have been identified for conversions, and those without will have new telescopes built, with construction expected to start in the 2020s.
Madagascar and Zambia are next on the list to have their telescopes converted. Loots says the location of the next conversion will depend on which country first establishes its governance structures — the entities within the government that will be responsible for overseeing the conversion and ultimately maintaining the telescope.
There is no clarity about where the money for future conversions and new builds will come from.
But for the next two years, South African and Ghanaian astronomers and engineers will be commissioning the Kuntunse dish, ironing out the bugs and ensuring that the telescope can do good science.
Loots says the African VLBI Network is not "a sprint. It’s definitely an ultramarathon. In other African countries, we’re setting up 10-year programmes. A programme taking a youngster from matric to a PhD is a 10-year programme."
Ghanaian Environment, Science, Technology and Innovation Minister Kwabena Frimpong-Boateng, says while it is great that African computer scientists, astronomers and engineers are trained in SA, "we should be careful not to see this as a one-way affair".
Science, technology and innovation have to deliver tangible results in terms of employment, patents, new businesses "and above all, the contribution to our gross domestic product", Frimpong-Boateng says.
If these benefits are not realised, Ghanaians "will think we are wasting money".
Asked whether there is resistance to SA exporting its prioritisation of radio astronomy to other countries, Pandor says: "If it is a good export, why would anyone have a problem with it?"
• Wild was a guest of the Department of Science and Technology in Accra, Ghana.