Star trek via the Karoo
SKA brings benefits, from local universities to high school pupils in Carnarvon
It’s a little-known fact that Cape Town had eight computers in 1879, and 12 in 1907.
They were not paid very well but they did important work. Computer was the name given to assistants to the astronomer royal at the Royal Observatory, Cape of Good Hope, and compute is what those people did. Every day they would do hundreds of mathematical calculations based on the observations of the night before.
In 1882 the Royal Observatory achieved worldwide fame when the Great Comet was recorded at this outpost of empire better than anywhere else on the planet. Astronomer David Gill mounted a portrait camera on the same apparatus as the telescope and achieved remarkable clarity of image of the comet and the surrounding stars. And so a new era in charting the heavens began, using photography.
Another new era in astronomy has arrived and though the building in Observatory has no role to play, South African astronomy is again at the forefront of global innovation.
That’s because what the observatory in Observatory offered was optical astronomy and radio astronomy is now the new big thing. On clear, dark nights, stars can still be seen on the site of what is now called the South African Astronomical
Observatory. The organisation that controls the facility and goes by the same name, SAAO, also operates four optical telescopes near Sutherland in the Karoo, including the Southern African Large Telescope. They still do important work.
As Adrian Tiplady, deputy MD of strategy & partnerships for the South African Radio Astronomy Observatory (SARAO), explains, radio astronomy does not need dark skies. What matters is to have as few signals bouncing around the sky as possible. “You want to build a radio telescope where there is a very low population density,” says Tiplady. “That means a low demand on communication services.”
Thus the Karoo is the site for optical instruments as well as the South African component of a vast new global radio astronomy project near Carnarvon. The Square Kilometre Array (SKA) project aims to build the world’s largest radio telescope, with a collection area of a square kilometre. The SARAO is the South African partner in this global effort.
Tiplady describes the project’s vast ambition: “It gives us a clue as to the evolution of the universe.”
The South African MeerKAT radio telescope, a forerunner of SKA, has already been built and its 64 dish antennas have started delivering images of extraordinary clarity from the centre of our galaxy.
But SKA is already delivering something else. Tiplady says that deliberate efforts have been made to “lower the barriers of entry to educational and economic opportunities which may arise from SKA”.
An artisan training centre has been established and Tiplady is proud that, for another sophisticated programme, most of the telescope was built by local technicians and artisans.
Maths and science teachers have been deployed at Carnarvon High School and, says Tiplady, “we are in close collaboration with Sol Plaatje University. They have data science, and we support students who want to study there.”
The calculations generated by the dishes in the Karoo are today recorded close to the site of the old Royal Observatory in Cape Town, but the computers now receive no pay at all.
Off in the other direction, about 600km southeast of the Karoo site, radio astronomy thrives at Rhodes University.
This is where Ntsikelelo Charles, an honours graduate in physics, is studying for a PhD in radio astronomy with the support of the SARAO. He remembers a Rhodes lecturer on
an outreach visit to his school, Ntsika Senior Secondary in Makhanda (Grahamstown), sparking his curiosity.
One of the leaders of the Rhodes Centre for Radio Astronomy Techniques & Technologies, Prof Justin Jonas, saw Charles’s interest in maths and told him about SKA.
“As undergraduates we could choose which field to go into, and he told us about radio astronomy and how cutting edge the science was,” remembers Charles. “It was really exciting to think that it was going to be in South Africa.” He has a “keen interest” in research and sees himself either at an institution such as the SARAO or as a university professor.
Six years later he’s still involved but for all the travelling he’s done to the outer reaches of the galaxy, it’s all been done remotely.
Plans to visit radio astronomy sites in South Africa were shelved because of Covid restrictions. Would travelling to an overseas posting be something he would consider? “Any international experience would be fantastic,” says Charles.
Offers on a postcard. Or by computer.