CATAC Update on the Thirty Meter Telescope

By / par Michael Balogh (CATAC Chair)
(Cassiopeia – Autumn / l’automne 2018)

Science Forum

Registration has now opened for the next TMT Science Forum, to be held December 10-12 in Pasadena, California. Please note that registration is free for students and members of the International Science Development Teams (ISDTs). In addition, ACURA has agreed to provide some travel support for University-based researchers who wish to attend this meeting, given its importance to the future success of TMT. To apply for this funding, please email with a short description of your involvement in TMT, and your need for funding support.

Among other things, the Science Forum is an excellent opportunity for ISDT members to meet face to face. With Canada recently stepping up to join these ISDTs at an appropriate level, this is the time to take advantage of that membership to ensure your science interests are represented as TMT develops.


The TMT Science Advisory Committee (SAC) is meeting Sept 12-13, and one of their main agenda items is to discuss progress with the Wide Field Optical Spectrograph (WFOS) design. The instrument team continues to work on advancing two possible designs: one using traditional slitmasks (Xchange) and another using optical fibers, over a wider field of view. At a recent, independent cost review, both instruments were found to significantly exceed the $50M cost cap when appropriate contingency is included. A subcommittee has been evaluating the scientific implications of proposed descope options for both designs, and will be reporting to the SAC at this meeting.

The other item before the SAC is a report from a subcommittee that has been considering white paper submissions for the next instrument to be constructed, after WFOS and IRIS. The SAC is in the process of reviewing and prioritizing the submissions, with a goal of identifying one or more studies for possible design funding.

Of likely relevance to future instrumentation discussion will be the Exoplanet Science Strategy report recently released by the U.S. National Academies of Science, Engineering, and Medicine (NASEM). The full report is available here. In particular, it recognizes the pivotal role that both TMT and GMT will play in the study of planet formation, and recommends that the National Science Foundation (NSF) invest in both the GMT and TMT and their exoplanet instrumentation to provide all-sky access to the U.S. community.

Funding and Construction Developments

In August, the Hawai’i Supreme Court ruled in favour of TMT regarding the case of the sublease. The issue at stake here was a possible requirement to conduct a contested case hearing for the granting of the sublease, as was done earlier this year for the Conservation District Use Permit (CDUP). The court ruled, unanimously, that a contested case hearing is not required for the sublease.

The remaining case before the Supreme Court is the appeal of the Land Board’s decision to award the CDUP itself. A decision is expected in the coming weeks, hopefully before the Board meeting in October. Coincidentally, the permitting process for the alternative site in the Canary Islands (ORM) is expected to conclude, following unanticipated bureaucratic delays.

As recently announced, the US community is now working under the leadership of NOAO to prepare a proposal for US participation in both TMT and GMT. If this is well received by the US Decadal planning process, it may pave the way for substantial (25%) NSF involvement in the project. A potential complication is that NSF participation will likely trigger the need for a federal Environmental Impact Statement (EIS). Depending on how this is staged, it could lead to further delays. No such EIS would likely be required for construction on ORM, La Palma. The Board is expected to make a site recommendation this October. CATAC will be revisiting our site selection report and recommendations from May 2017 to identify anything that might have changed or need more research, so that we can reaffirm or modify our recommendations as necessary. Continued input to CATAC on this important issue is still welcome.

Bookmark the permalink.

Comments are closed.