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Thirty Meter Telescope (TMT)

Thirty Meter Telescope (TMT)is a next generation optical/infrared telescope with an aperture of 30m, which will be operational in 2027 atop Maunakea on the island of Hawaii. In comparison to the 8.2m Subaru Telescope, one of few telescopes currently at the forefront of astronomical observation, TMT will have 13 times the light-gathering power and 3.6 times the resolving power, enabling it to perform at an unprecedented level of sensitivity. Utilizing this power to its fullest extent, TMT will aim to search for evidence of life on extrasolar planets and to reveal the identity of astronomical objects in the very early universe.


An artist's rendering of TMT

International Collaboration and Contributions by Japan

The TMT project is driven by international collaboration consisting of five partner countries including Japan, USA, Canada, China, and India. NAOJ is moving forward with the TMT project, with Japan expected to contribute by covering a quarter of the total construction cost of TMT. For its share of contribution, Japan is taking charge of the design and manufacture of the main telescope structure, production of all of the mirror blanks for the primary mirror (574 blanks including those for replacement), and performing a portion of the surface polishing of the segment mirrors. Japan also has a significant role in promoting scientific planning for TMT and in developing science instruments for the telescope.


Rendering of the main telescope structure designed by Japan


Manufacturing of the mirror blanks in Japan put into mass production in 2013.


Prototype of a segment mirror polished in Japan (2011).
The 82nd segment which has the largest asphericity was polished
to demonstrate that the polishing technique is above the required level.

TMT and the New Era of Astronomy

(1) The first stars and the dawn of the galactic cosmos

The Subaru Telescope has contributed to the miraculous progress in mapping out the full picture on how structures including galaxies and galaxy clusters formed and developed during the early history of the universe. TMT will endeavor to observe an even earlier Universe by capturing light from first galaxies and supernova explosion of the first stars, and uncover the entire history of the dawn of the galactic cosmos glimpsed today by the Subaru Telescope by studying objects discovered by the Subaru Telescope in further detail with high-resolution imaging /spectroscopy.


Image of deep space taken by the Subaru Prime Focus Camera.
An image captured of a galaxy from 12.9 billion light years away
(Enlarged view on top left).

(2) In search of life on extrasolar planets

Many planetary systems around stars other than our sun are being discovered today, and we are learning that there exist planets with various sizes and orbits. Recently, planets similar in size as earth were discovered, indicating that there are planetary systems much like our own solar system. Today, infrared observation has advanced to a point of being able to actually capture images of extrasolar planets. Are there extrasolar planets with existence of life? This is a question common to all mankind. TMT will answer this question by searching for signatures of biological activity in planetary atmospheres.


The least massive exoplanet imaged by Subaru Telescope.
GJ 504b (upper right) is estimated to be 3-5.5 times the mass of Jupiter.
TMT will attempt to directly capture even smaller earth-like planets.

Collaboration with the Subaru Telescope

The Subaru Telescope has particularly contributed to astronomical observations by taking advantage of its field-of-view that is exceptionally wide for a large telescope. This was made possible by a science instrument mounted at the primary focus of the telescope. The Hyper Suprime-Cam (HSC), which was installed in 2012, has further significantly increased its ability to survey wide areas of the night sky. In the 2020s, with the arrival of TMT, studies can be performed in which the Subaru Telescope is assigned to discover objects that are candidates for furthest galaxies, and TMT is given the task of performing detailed investigation of their properties. This collaboration between TMT and the Subaru Telescope will support Japan in its effort to lead the world in astronomy.


An artist's rendering of TMT with laser from the laser guide star system illuminated.
In the background is the dome of the Subaru Telescope.