Hawaii’s Thirty Meter Telescope Could End Up in the Canary Islands

The group behind the contested project is still pushing for construction on the Big Island, but has selected an alternate site just in case.

An artist's rendering of the Thirty Meter Telescope at sunset (TMT)

Construction plans for the largest telescope on Earth remain uncertain, but a possible alternative future for the Thirty Meter Telescope project is beginning to take shape.

Plans for the massive observatory, originally intended to be built atop a huge shield volcano on the Big Island of Hawaii, have stalled out since last year amid a lawsuit from those who oppose the telescope project—including some Native Hawaiians, activists, and other cultural practitioners who believe the volcano, Mauna Kea, is sacred.

The Thirty Meter Telescope’s International Observatory Board decided late last month that if they cannot move forward with building the telescope in Hawaii, they will instead choose La Palma, one of Spain’s Canary Islands.

The Gran Telescopio Canarias, or Great Canary Telescope, is the massive reflecting telescope already located at La Palma. For now, it holds the distinction of being the largest single-aperture optical telescope in the world.

The nonprofit group that’s building the Thirty Meter Telescope began scoping out other sites for the $1.4 billion telescope this fall—including mountains in Chile, India, China, and Mexico, according to the Honolulu Star-Advertiser.

But Doug Simons, an astronomer and the executive director of the Canada-France-Hawaii telescope on Mauna Kea, emphasized to me that he and his colleagues aren’t giving up on Hawaii as the ultimate home for the TMT just yet. They still believe that Mauna Kea—with its high elevation and remote location in the middle of the Pacific—is the best place on the planet for the kind of scientific discovery that the TMT would enable, but “every site we considered would enable TMT’s core science programs,” said Henry Yang, chairman of the TMT International Observatory Board, in a statement.

Construction of the telescope was halted indefinitely in December 2015 when the Hawaii Supreme Court decided that the state did not follow the proper process when officials granted a construction permit to the University of Hawaii for the project.

“The focus in Hawaii remains on the contested case hearings, which appear to be set to go on into early next year,” Simons said in an email. “Most still expect that TMT will get their permit reinstated, which will trigger an immediate appeal to the Hawaii Supreme Court, sometime next year.”

Simons has said in the past that moving the project away from Hawaii would be “absolutely devastating” to astronomy. “In modern astronomy, you must go with the biggest telescope you can build to the tallest mountain you can find,” Paul Coleman, an astronomer and physicist at the University of Hawaii, told me last year. “That is the defining thing for astronomical growth.”

Given Hawaii’s history of colonialism, including the 1893 overthrow of the Hawaiian Kingdom, land-use issues in the Islands are particularly fraught.

“I’m glad they’re looking at alternative sites,” Kealoha Pisciotta, the leader of an organization dedicated to protecting Mauna Kea from development, told the Star-Advertiser. “I have to say if they do go with the alternative site, I hope they don’t do there what they’re doing to Native Hawaiians and the people of Hawaii.”

There are already 11 operational telescopes on Mauna Kea. Among them are Keck 1 and Keck 2, the next-largest reflecting telescopes on Earth after the Gran Telescopio Canarias.