After years of hearings and litigation, the Supreme Court of Hawaii on Tuesday approved a building permit for a giant telescope on the ancient, contested site of the volcano Mauna Kea.

The Thirty Meter Telescope, as it is known, would be the largest ever contemplated in the Northern Hemisphere. Hawaiian activists have opposed it, saying that decades of telescope-building on Mauna Kea have polluted the mountain. Some of them went so far as to block construction vehicles from the mountain to prevent work on the telescope.