Tests have begun on one of the world's largest optical telescopes, installed on a mountain in the Canary Islands.
Situated on a 2,400m-high (7,900ft) peak on the island of La Palma, the huge telescope consists of a mirror measuring 10.4m (34.1ft) in diameter.
The Spanish-led Great Canary Telescope (GTC) is extremely powerful and will be able to spot some of the faintest, most distant objects in the Universe.
More: http://news.bbc.co.uk/1/hi/sci/tech/6897293.stm