News

WFOS team and Review Panel

WFOS Preliminary Design Review 1 Successfully Completed

The Thirty Meter Telescope (TMT) International Observatory (TIO) is delighted to announce the successful completion of the Preliminary Design Review 1 (PDR-1) for the Wide Field Optical Spectrograph (WFOS), held on August 7–8, 2025, at the TIO Project Office in Pasadena, California, and via Zoom.

An international panel of experts carefully evaluated the design and concluded that WFOS is ready to advance to its next design phase. This review marks an important milestone for TMT and underscores the strength of the collaboration across the partnership.

WFOS team and PDR1 Review Panel

WFOS, led by Principal Investigator Chuck Steidel of Caltech, with Eric Peng of NOIRLab serving as Project Scientist, is being developed with major contributions from Caltech (USA), the India TMT Coordination Center (ITCC), and the National Astronomical Observatory of Japan (NAOJ).

PI Chuck Steidel describing how Keck MOSFIRE heritage will benefit WFOS.

Designed to capture spectra of nearly one hundred galaxies or stars at once, WFOS will be a workhorse first-light instrument, advancing studies of galaxies, stars, and the intergalactic medium.

The PDR-1 panel praised the team’s progress, highlighting strong systems engineering, innovative design features such as the configurable slit mask system, and the broad scientific reach WFOS will bring to TMT and the astronomy community.

Left: Rendering of WFOS on the TMT Nasmyth platform. Right: Artist’s conception of mapping the intergalactic medium using light from background galaxies. WFOS on TMT has the sensitivity and field of view needed to reconstruct a 3D map of this critical material between galaxies. Credit: C. Stark and K. G. Lee

When completed, WFOS will open an unprecedented window on the universe, enabling discoveries across nearly every field of astronomy and helping to realize the extraordinary potential of the Thirty Meter Telescope International Observatory.