Overview

When completed, the Thirty Meter Telescope (TMT) will be the world’s largest ground-based optical/infrared telescope. Between 2003 and 2007, the Foundation funded $50 million to complete a detailed design study for the TMT. In December 2007, the Foundation pledged an additional $200 million for completion of the design and early construction phases, and the construction phase. In March 2009, the TMT successfully completed its five-year Design Development Phase. The Early Construction Phase commenced on April 1, 2009.

The TMT observatory will enable researchers to peer back in space and time to the formation of the first stars and galaxies, and will directly image planets orbiting other stars. The TMT will be located on Mauna Kea, where atmospheric conditions, low average temperatures, and very low humidity will contribute to extremely advantageous viewing conditions. 

Watch an overview, courtesy of TMT: 

The telescope will represent the forefront of technology in every aspect of its design:

• The structure will consist of a primary mirror with 492 individual 1.45-meter segments that together measure 30 meters in diameter, providing more than nine times the collecting area of the current largest telescope.
• All mirrored segments will be guided with precision computer control in order to work together as one single mirror, building on the technology developed for the 10-meter mirrors in the two Keck telescopes in Hawaii.
• Adaptive optics (AO) will allow the TMT to achieve a resolution superior to that of the Hubble Space Telescope, using six laser beams to create six luminous spots in a layer of sodium atoms high in Earth's upper atmosphere. These bright artificial stars serve as references for measuring the turbulence in the atmosphere, allowing the AO system to compensate for blurring of starlight by Earth's fluctuating atmosphere. This technology was pioneered at the Lick Observatory 3-meter telescope and has been developed further at the Palomar 5-meter and Keck 10-meter telescopes.

The TMT project is an international collaboration. Along with Caltech, UC, and the Association of Canadian Universities for Research in Astronomy (ACURA), significant work is being done by industry and university teams studying instrument designs. The National Astronomical Observatory of Japan is also a "Collaborating Institution" and the National Astronomical Observatories of the Chinese Academy of Sciences has been designated an "Observer Institution." In June 2012, India committed to spending at least $100 million towards the Thirty Meter Telescope project, becoming the first government to make such a commitment. The project office is in Pasadena, California.