SANTIAGO, Chile -- Astronomers in Chile are blasting away the top of a mountain to install what they say will be the world's largest optical telescope.

The 9,800-foot Cerro Armazones mountain will be the new home of the European Extremely Large Telescope.

Thursday's blast is being overseen by officials at the European Southern Observatory in northern Chile.

Their ground-based telescope has a 128-foot mirror, and the astronomers are calling it "the world's biggest eye on the sky." They say it will help advance the study of planets around other stars, dark matter and supermassive black holes.