With 16 member countries and a treaty that guarantees a fixed annual income, ISO can pay for ILT without serious sacrifices; However, a few years ago, he had to reduce the diameter of the mirror from 42 meters, which was originally planned, to 39 meters.
On the other hand, the international consortium supporting the construction of TMT and GMT is facing many challenges. Despite having international partners in Australia, Brazil, South Korea, Japan, India, Canada and China, these projects have faced the suspension of attracting financial aid. According to Richard Ellis, an astronomer at University College London, it is unrealistic for universities and private institutions to manage multi-billion dollar projects. Even the US government would probably only be able to support one of the telescopes.
In addition to the budget problem, the Giant Magellan Telescope is struggling with another problem. Choosing the place to build this telescope near the peak of Mauna Kea on the Big Island of Hawaii has resulted in the opposition of the local people, including the native Hawaiians. Protesters, who do not want another telescope to be built on the sacred mountain, first prevented construction from starting in 2015. The second attempt in 2019 was stopped after protesters set up a camp along the road leading to the peak.
However, TMT and GMT continue to operate with the same budget they have. Three of the seven 8.4-meter GMT mirrors have been completed and are now being polished. Last month, technicians at the University of Arizona poured 20 tons of glass into a circular mold to form the final mirror. The glass will gradually heat up to a temperature of 1165 degrees Celsius and will give the mirror a parabolic shape with slow rotation.
At the GMT construction site at Las Campanas Observatory in Chile, seven mirrors will be combined to form the 25.4-meter-diameter main reflector. In contrast, TMT, like ILT, will consist of a mosaic of smaller mirrors; An approach that was pioneered in Keck’s 10-meter telescopes. At the American company Coherent, a monthly assembly line polishes three one-and-a-half-meter mirrors before cutting them into hexagons. While Coherent is manufacturing 230 mirror parts, other teams in India, China, and Japan will produce the remaining 492 parts required for the TMT (plus 80 spare parts).