The quest to build one of the world’s largest telescopes has radically reshaped the future of a Hawaiian mountain. On 26 May, Hawaii governor David Ige announced that the controversial Thirty Meter Telescope (TMT) could be built on Mauna Kea as planned — but that three or four of the mountain’s 13 existing telescopes must be dismantled over the next decade.
Mauna Kea is home to such world-leading facilities as the twin 10-metre Keck telescopes and the 8-metre-class Subaru and Gemini North telescopes (see ‘Starry summit’). Speculation is already running high about which telescopes will be removed, and when.
Native Hawaiians regard Mauna Kea as sacred, and they view building the TMT as another violation of an already desecrated site. Construction was to have begun in early April, but was put on hold when protests broke out on the mountain, in Honolulu and at other sites across the islands.
Ige’s announcement, a direct response to the unrest, accelerates long-standing plans to decommission Mauna Kea telescopes as they grow older. “The idea of removing telescopes from the summit is not a new one,” says Doug Simons, director of the Canada-France-Hawaii Telescope on Mauna Kea. “It’s the natural evolution of a set of observatories that are ageing in a lot of ways.”
The governor has ordered the University of Hawaii at Manoa, which leases the mountain top as a science reserve, to close 25% of the observatories there before the TMT begins operation in the mid-2020s. The university owns a 2.2-metre optical telescope that is the oldest on Mauna Kea, dating back to 1970; a 0.9-metre educational optical telescope; and the 3.8-metre United Kingdom Infrared Telescope (UKIRT). It also manages the 3-metre Infrared Telescope Facility for NASA, which studies planets, asteroids and stars.
“We have always made the point that space on the top of the mountain should only be populated by the absolutely best telescopes,” says Günter Hasinger, director of the university’s Institute for Astronomy.
The first to go will be the Caltech Submillimeter Observatory, the closure of which was announced in 2009. It will end operations in September, and then will be dismantled. Other telescopes, including Keck, Gemini and Subaru, involve complex international agreements that cannot be overwritten by the state of Hawaii alone. All have committed to operating on the mountain to the end of 2033.
“We intend to continue operating until we come to a point where the science return isn’t worth it,” says Raymond Blundell, an astronomer at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts, and director of the Sub-millimeter Array, an eight-dish radio telescope array on Mauna Kea.
Some of the telescopes on the mountain have just begun a new lease of life. Earlier this year, a consortium of east Asian observatories took over the submillimetre-wavelength James Clerk Maxwell Telescope to study how galaxies and stars form, among other things. And UKIRT has just begun a long-term science programme that involves studying space debris and near-Earth asteroids, says director Richard Green, an astronomer at the University of Arizona in Tucson.
For now, Green continues to plan for nearly two decades ahead — although he acknowledges that the situation may change. “We realize there has to be more attention paid to the culture and how the mountain is taken care of,” he says.
In addition to closing telescopes, Ige levied a list of other requirements. When the University of Hawaii’s lease ends in 2033, it must return to state protection more than 40 square kilometres of the 45 it leases. Visitors to the summit must receive cultural training. And the TMT location, which is a few hundred metres beneath the actual summit, will be the last area on Mauna Kea on which any telescope will ever be built.
Nearly every telescope project on Mauna Kea in recent years has faced local protests, although not the sustained high emotion inspired by the TMT. John Johnson, an astronomer at Harvard University in Cambridge, says that astronomers should not be on the mountain top at all, given the history of the Hawaiian Islands. “This goes way beyond whether we construct this telescope or not,” he says. “It has to do with the fact that the United States stole Hawaii from a sovereign people and proceeded to systematically erase that culture.”
The university says it will have a plan for removing 25% of the observatories by the end of this year. The TMT has not announced whether and when it will resume construction, and legal challenges to the project are still wending their way through Hawaiian courts.
Two competing next-generation telescopes are being planned for Chile.
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