The TMT design is a response to a set of science-based requirements developed by the TMT Science Advisory Committee (SAC), a committee of scientists representing all the TMT partners and (by extension) the future TMT scientific user community.
Central to these requirements are descriptions of a suite of eight instruments conceived to attack the key science problems of the first decade of TMT operations. Starting from these descriptions, detailed conceptual design studies were commissioned from instrument development teams throughout North America. These conceptual designs were reviewed by non-advocate review teams with members from North America and Europe.
Based on these studies and reviews, the SAC has selected three early light instruments: a wide-field, multi-object spectrograph working at optical wavelengths called WFOS; an integral-field unit spectrometer with imaging capability working at near-infrared wavelengths called IRIS; and a multi-slit, near-infrared spectrometer with imaging capability called IRMS. The latter two instruments will be fed by a facility AO system called NFIRAOS to achieve full diffraction-limited sensitivities and spatial resolutions in the near-infrared. These three instruments will be capable of exploring the wide astronomical terrain: from the first stars in the Universe to planets orbiting nearby stars.
The rest of the SAC suite, the first decade instruments, will be developed and deployed on a schedule paced by a combination of technological readiness and available financial resources. Naturally, TMT maintains the flexibility to investigate and deploy different instrument concepts in response to scientific and technological developments over the next decade.
First Light Instruments
Wide Field Optical Spectrometer (WFOS)
The Wide Field Optical Spectrometer (WFOS) will provide near-ultraviolet and optical (0.3 – 1.0 μm wavelength) imaging and spectroscopy over a more than 40 square arcminute field-of-view. Using precision cut focal plane masks, WFOS will enable long-slit observations of single objects as well as short-slit observations of hundreds of objects simultaneously. WFOS will use natural (uncorrected) seeing images.
Infrared Imaging Spectrometer (IRIS)
The Infrared Imaging Spectrometer (IRIS) will be mounted on the observatory MCAO system and be capable of diffraction-limited imaging and integral-field spectroscopy at near-infrared wavelengths (0.8 – 2.5 μm).
Infrared Multi-object Spectrometer (IRMS)
The Infrared Multi-object Spectrometer (IRMS) will allow close to diffraction-limited imaging and slit spectroscopy over a 2 arcminute diameter field-of-view at near-infrared wavelengths (0.8 – 2.5 μm).