Thirty Meter Telescope

Astronomy's next generation observatory.

About TMT

Science Advisory Committee

The Science Advisory Committee (SAC) is a committee of the Thirty-Meter Telescope International Observatory LLC (TIO) Board of Directors. The SAC is an advisory committee, representing the scientific interests of the TIO Members, including making recommendations to the Board regarding science priorities and instrumentation.



  • Judith (Judy) Cohen, Caltech
  • Chris Martin, Caltech
  • B. Thomas Soifer, Caltech (Board representative)
  • Charles (Chuck) Steidel, Caltech (SAC Chair, CIT co-chair)


  • Roberto Abraham, University of Toronto
  • Timothy (Tim) Davidge, NRC/HIA (Canada co-chair)
  • Stanimir Metchev, University of Western Ontario 
  • Doug Welch, McMaster University (Board representative)


  • Fang Taotao, Xiamen University (China co-chair)
  • Hao Lei, Shanghai Astronomical Observatory
  • Gregory Herczeg, KIAA-PKU, Eric Peng, Peking University (shared)
  • Xue Suijian, NAOC (Board representative)


  • Shashi Pandey, ARIES
  • B. E. Reddy, IIA (Board representative)
  • T. Sivarani, IIA
  • R. Srianand, IUCAA (India co-chair)


  • Masayuki Akiyama, Tohoku University
  • Mitsuhiko Honda, Kurume University, Taro Matsuo, Osaka University (shared)
  • Nobunari Kashikawa, NAOJ (Japan co-chair)
  • Tomonori Usuda, NAOJ (Board Representative)

University of California

  • Michael Bolte, UC Santa Cruz (Board representative)
  • Lori Lubin, UC Davis
  • Garth Illingworth, UC Santa Cruz (UC co-chair)
  • Tommaso Treu, UCLA


  • Ian Dell'Antonio, Brown University
  • Mark Dickinson, NOAO (US Community co-chair)
  • Karen Meech, University of Hawaii
  • Catherine (Caty) Pilachowski, Indiana University (Board representative)

University of Hawaii

  • Lennox L. Cowie, University of Hawaii

Ex officio

  • Jerry Nelson, Project Scientist

SAC Composition

The SAC is composed of regular members and ex-officio members who are appointed by the Board of Governors of TMT International Observatory (TIO). Each Member may nominate up to three representatives to serve as regular SAC members plus one ex-officio member who is also a member of the Board. Each Associate may nominate up to three representatives to serve as regular SAC members and one ex-officio member who also participates on the TIO Board as defined in that Associate’s Memorandum of Agreement. During the term of the TMT sublease with University of Hawaii, University of Hawaii may nominate one representative to serve as a regular member of the SAC. In addition, the Project Scientist is an ex-officio member of the SAC. The SAC may recommend to the Chairperson of the Board nominations for SAC membership. Non-voting observers to the SAC from entities considering joining TMT may be approved by the Governing Board.

SAC Charter

The SAC co-chairs meet biweekly by telephone. Meetings of the complete SAC normally occurs 4 times per year.

SAC responsibilities include:

  • With the Project Scientist, establish and maintain the top-level science requirements of the observatory. These are embodied in the Science-based Requirements Document (SRD) and follow from the scientific capabilities requested by the TMT partner communities.
  • Assist the TMT project team with the translation of the SRD requirements into technical requirements. Work with the project to resolve differences or inconsistencies between the SRD and project Observatory Requirements Documents.
  • Develop and maintain a scientific strategic plan. This plan will identify and describe key TMT scientific capabilities.
  • Advise the Board on the selection of TMT instrument concepts, including adaptive optics, for further study and ultimately on the selection of instruments and adaptive optics systems to be built.
  • Provide science-based advice to the Board, the Observatory Director, the Project Scientist and, during the construction phase, to the Project Manager. During the operational phase, provide advice regarding all scientific aspects of operations and provide regular assessments of the scientific productivity and operational efficiency of the observatory.
  • Act as a liaison with the TMT partner communities regarding science requirements, prioritization of capabilities and operations modes. Work to engage and inform the communities about the capabilities and scientific potential of the observatory.