China is planning to build a world-class observatory in southwestern Tibet [Images] Autonomous Region, also called 'the world's roof,' the state media reported on Tuesday.

"A preliminary survey has found that Sengge Zangbo town in Ngari Prefecture, western Tibet, may be an ideal place to launch the world's largest and most advanced telescope with a calibre up to 100 meters," said Ai Guoxiang, who heads the National Astronomical Observatories.

Sengge Zangbo, 4,800 meters above sea level, is surrounded by mountains. It is quiet, dry and usually has clear night skies.

"The crown of 21st century's ground-based astronomy will be in China if further investigation proves the same," Xinhua
news agency quoted Ai as saying.

An alternative location for the new observatory could be Taxkorgan county in the Xinjiang Uygur Autonomous Region,
northwest China, he added.

Chinese scientists will carry out astronomical observations from fixed positions in these two places for a year or two before the final decision is made, according to Ai.

"When the location is confirmed, we'd suggest China cooperate with some Southeastern countries in building an optical/infrared telescope with a calibre of 10 meters," he said.