Scientists carried out the last step in testing a key component of China's gigantic radio telescope on Nov 21. After its scheduled completion next September it will be the largest such telescope in the world.

A team successfully tested the installation of the telescope's "retina", a mechanism weighing 30 metric tons and suspended 140 to 160 meters above the half-finished reflector dish, which will collect signals from the universe.

The telescope, 500 meters in diameter, is composed of 4,500 mostly triangular panels with sides measuring 11 meters that create a parabolic shape or hemisphere. The motion of the panels alters the collective shape of the antenna, which is capable of reflecting radio signals from the universe to a focal point, where the receiver dome sits.