A decision on the site of the planned Thirty Meter Telescope (TMT), whose licence for construction in Hawaii was revoked in December last year, will be made in early 2017.
Representing the TMT organization, Fengchuan Li told delegates at the SPIE Astronomical Telescopes and Instrumentation conference in Edinburgh, UK, that sites in Baja California in Mexico, the Canary Islands, and Chile were now being evaluated as alternatives.
Public-private partnership
A collaboration between private partners in the US, and public partners in Canada, China, Japan and India, TMT had been planned to build on the heritage of the Keck and Gemini telescopes in Hawaii, where optical technologies such as segmented mirrors and laser guide stars have been pioneered.
But after some of the local residents of Mauna Kea protested against the construction when early work had started on what they believe to be a sacred site, a local judge ruled that due process had not been followed when local authorities originally approved the permit to build TMT at the summit.
Li stressed that despite the licensing problem in Hawaii that halted construction, work on the wider project has continued where possible. “The team is not sitting idle,” he said. “We are making progress and spending every dollar wisely.”
Li also said that the TMT board was meeting each month and attempting to make progress in Hawaii, but added: “The goal is to make a decision [on the TMT site] by early 2017.”
Design reviews ongoing
In the meantime, the final design review for the 492-segment active primary mirror is scheduled for November this year, while the Chinese team responsible for TMT’s laser guide star system will complete its design review in 2017. The sophisticated adaptive optics system envisaged is expected to generate images ten times sharper than the Hubble Space Telescope once it is up and running.
The TMT’s enormous dome, which will be 56 m high once completed, will eventually house a Ritchey-Chrétien design, three-mirror optical system. The convex secondary mirror measures 3.2 m in diameter, while the tertiary mirror will move in two axes, directing light to scientific instruments on both sides of the structure.
Canada’s Dynamic Structures has been signed up to build the telescope enclosure, while Japan’s Mitsubishi Electric is building the telescope itself. M3 Engineering is to construct the summit facility.
Responding to audience questions in Edinburgh, Li said that if a different site was now selected, there may be a need to redesign the telescope enclosure because of different wind conditions compared with Mauna Kea. But he said that this was not a “showstopper” for the project.
