SAfrican telescope proving worth its SALT

South Africa’s SALT telescope has helped detect the first white dwarf pulsar, the latest co-discovery that has astronomers eager to use the largest optical telescope in the southern hemisphere to unlock the galaxy’s secrets.


Quick reaction times, as well as being significantly cheaper than similar European or American facilities in producing the science are key competitive advantages, said a senior astronomer at the SALT consortium during a media visit.

“SALT is now living up to expectations, producing high-quality science data that probe the far reaches of the universe,” said Ted Williams, a director at the South African Astronomical Observatory managing the site.

Scientists know of neutron stars, large objects about the size of the Sun that have compacted down at the end of their lives to something about 10km across, the last stop before a black hole.

Williams said these incredibly dense objects have been known for decades to produce pulsars, which emit regular pulses of radio waves and other electromagnetic radiation at rates of up to one thousand pulses per second.

“But there is another class of compact objects called white dwarfs, bigger, the size of the earth. So rather than 10 kilometres in size we are looking at 6000 kilometres and we’ve just discovered the very first white dwarf pulsar,” he said of the previously unknown celestial phenomena.

Situated atop a hill in the desolate Northern Cape around 350km north of Cape Town, the $US43 million ($A56 million) SALT telescope used its powerful spectroscopy light measurement tool to prove the existence of the white dwarf pulsar.

Shared by a consortium of partners from South Africa, India, America and Europe, SALT’s queuing system allows it to interrupt routine observations and within minutes focus its 10-metre optical telescope on new discoveries, said Williams.

In February, SALT was the first major telescope to take a spectrum of a supernova in the nearby Centaurus A galaxy hours after its discovery.

It also helped reveal one of the biggest explosions ever recorded in the universe, 200 times more powerful than a typical supernova and believed to have shone at 570 billion times the brightness of the Sun.

Together with Australia, South Africa is also co-hosting the world’s biggest and most advanced radio telescope, the $US2 billion ($A2.6 billion) “Square Kilometre Array” which will study the origins of the universe and help probe for extraterrestrial life.