South African scientists on the verge of creating an African Telescope Network

South African scientists, with government backing, are working on a project to recycle disused  telecommunications dishes spread out over a number of African countries in order to create
an African network of radio telescopes.

In June last year, the board of the African Renaissance Fund, which is located in South Africa’s Department of International Relations and Cooperation, approved R120-million in funding for the initial work to construct a network of radio telescopes in Africa’s nine Square Kilometre Array (SKA) partner countries.

The Department of Science and Technology has been working with its counterparts in South Africa’s eight SKA partner countries – Botswana, Ghana, Kenya, Madagascar, Mauritius, Mozambique, Namibia and Zambia -since 2009 on ways to fund an African-owned network of radio telescopes.

The African VLBI Network project, which is being driven by SKA South Africa and the Hartebeesthoek Radio Astronomy Observatory (HartRAO) near Johannesburg, aims both to fill a major gap in the global VLBI network and, by boosting engineering and science skills development across the continent, to pave the way for the arrival of the SKA.

Very long baseline interferometry (VLBI) is an astronomical technique that uses widely separated radio telescopes in unison to simulate a single telescope hundreds or thousands of kilometres in diameter,
producing the clearest, highest resolution images of some of the most distant objects in the universe.

The greater the distance between the telescopes, the greater the resolution of the images produced in this way. Africa’s large north-south geographical spread would therefore make for a powerful VLBI

The costs of setting up such a network, however, seemed prohibitive – until HartRAO’s Mike Gaylard came up with the idea of converting satellite dishes, rendered obsolete by the arrival of fibreoptic
telecommunications cables, into radio astronomy antennae.

According to SKA South Africa, there are at least 26 satellite ground segment dishes, possibly more, spread out over Africa which could become a part of the new VLBI network.

Where countries do not have existing antennae suitable for conversion, converted dishes from other parts of Africa could be “transplanted”. In some cases, new dishes will be built. (Johannesburg)