Tmt comp background



A banner image to celebrate TMT’s 100th polished mirror. TMT’s 30 meter primary mirror will eventually be formed from a mosaic of 492 individual mirror segments. The fabrication of these mirror segments is an international effort with TIO members from the USA, Japan, and India. Image credit: TMT International Observatory

TMT International Observatory Produces its 100th Polished Mirror

Pasadena, CA – Today, the Thirty Meter Telescope (TMT) International Observatory (TIO) announces the completion of its 100th mirror segment. Ultimately, TIO will mosaic 492 of these segments to form an extremely large mirror 30 meters in diameter. This mirror will be the core component of the largest optical telescope in the Northern Hemisphere. With this powerful mirror, TMT will deliver images that are more than 12 times sharper than the Hubble Space Telescope and more than four times sharper than those from JWST.

Three organizations across TIO’s international partnership are producing the mirror segments: Coherent, Inc. in California, Canon, Inc. in Japan, and the Indian Institute of Astrophysics in India. TIO’s mirror segments build upon the successful technology created for the W. M. Keck Observatory. Scaling and advancing the Keck technology, TIO and its partners are developing innovative manufacturing techniques to achieve unparalleled levels of mirror precision and performance.
Ben Gallagher, optics group lead at TIO commented, “This is an exciting milestone. Making a mirror like this is a work of art.” Gallagher explained, “The tolerances on these mirrors are insanely tight…I like doing difficult things, and this is about as difficult as it gets.”
Fengchuan Liu, TIO’s project manager adds, “This milestone highlights the strength of TIO’s international partnership, with the U.S., Japan, and India contributing to the primary mirror production in close collaboration across scientific and industrial organizations. It’s a true reflection of TIO’s diverse, international nature and deep technological prowess.”
TIO Executive Director Robert Kirshner heralds today’s milestone as a significant achievement in advancing the observatory’s design. “Deeper understanding of the universe comes from bigger telescopes coupled to powerful instruments for detecting planets near stars, individual stars in distant galaxies, and galaxies at the edge of the universe.”
The 100th mirror segment celebrated today is a 1.5m diameter polished circular mirror. The unpolished mirror blanks are all supplied by Japan’s Canon, Inc. and Ohara, Inc. After the blanks are polished into mirrors, they are machined into the 1.44 meter (corner to corner) hexagonal mirror segments that will be assembled on support structures, aligned, and phased to perform as a single primary mirror. This 30 meter diameter primary mirror, combined with TMT’s advanced adaptive optics, will deliver exceptionally sharp images.
From probing the universe’s mysterious dark matter and dark energy to exploring the birth of the first stars, black holes, and galaxies to discovering Earth-like planets around other stars, observations with TMT will answer today’s most compelling astronomy questions while producing discoveries tomorrow beyond our current imagination.


TMT Polished Mirror Segment

One of the 492 polished mirrors that will become part of TMT’s 30 meter primary mirror sitting atop a support structure at Coherent Inc. in California. Image credit: Coherent Inc.

Rendering of The Thirty Meter Telescope

A digital rendering of the Thirty Meter Telescope, featuring its primary mirror composed of 492 individual hexagonal mirror segments. The Thirty Meter Telescope is shown at a very low elevation angle. Image credit: TMT International Observatory


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