Radio telescopes across Australia, China and Japan will Thursday launch a global 33-hour stargazing marathon to mark the start of the UN's International Year of Astronomy, scientists said.

Astronomers will follow three quasars -- J0204+1514, 0234+285 and 3C395 -- as they rise and set with the world's rotation, starting at 0800 GMT with telescopes in Australia, at Kashima in Japan, and China's Shanghai.

"This demonstration is an unprecedented and extraordinary feat of coordination, involving 17 telescopes and 28 data networks around the world," said Australian astronomer Chris Phillips of the government's science agency CSIRO.

Two CSIRO telescopes and a third university-owned dish in Australia would kick off the stargazing, which would also involve facilities in Asia, Europe, North America and South America, Phillips said in a statement.

Simultaneous data from Asia and Australia would be fed into a purpose-built supercomputer to produce extremely high-resolution cosmic radio images. Phillips said the images would be up to 100 times better than those from the best optical telescopes.

The demonstration coincides with the official launch of the International Year of Astronomy at the headquarters of UNESCO, the UN's science body, in Paris.