Tmt comp background

Second Generation Instruments

2017 Whitepaper Instrument Concepts


List of instrument concepts proposed for further study in the instrument white papers.

High-Resolution Optical Spectrometer (HROS)
 - 310-1100nm
 - R=25,000 to 100,000 (50,000 to ≥90,000)
 - Multiplex ≤100 (Single object)

InfraRed Multi-slit Spectrometer (IRMS)
 - 0.95-2.45µm, R=3270-4660 and Y,J,H,K imaging
 - 2.05x2.05 sq arcmin, 0.060 arcsec/pixel, AO with NFIRAOS
 - >80% EE in 0.12” by 0.16”, 46 adjustable 2.43 arcsec slits

Multi-IFU imaging spectrometer (IRMOS)
 - 0.84-2.4µm (0.8-2.5µm)
 - R=4000-10,000, full Y,J,H or K bands at 4000 (2000-10,000)
 - 2' patrol field (>2'), >10 IFUs, 0.5"@0.012"/spaxel, 1.06"@0.025", 2.1"@0.05 (3"x3"@0.05")
 - >50% EE in 0.05", overall efficiency 40% (>30%)

bMICHI - mid-IR AO Fed spectrometer imager IFU (MIRES)
 - 3-14µm (8-18µm)
 - R~600 long slit with polarimetry, 100,000-120,000 (5000-100,000)
 - R~1000 N-band IFU, 2x5 0.035" spaxels
 - 24.4"-28.1" FOV imager (10"), 0.012"/pixel@L,M, 0.028"/pixel@N (0.17") with polarimetry

Planetary System Instrument (PSI) 
 - 0.6-13µm with coronograph
 - Contrast ~10-8 @ 1–2λ/D
 - R=50-5000 IFU/imager with polarimetry (≤100)
 - R~100,000

Multi-fiber High-resolution NIR spectometer (MODHIS)
[Subsequently adopted for development as a first light instrument]
 - 0.95-2.5µm, fed by NFIRAOS
 - R~100,000, 30 cm/s velocity precision
 - Multiplex ~25 over 2"-5" with 0.1"x0.1" mini-IFUs@ 0.02" sampling

Astronomical Rapid Imager and Spectropolarimetric Explorer (ARISE)
 - 0.31-4.8µm simultaneous, R>15000
 - 5' FOV imaging @0.1"/pixel in u, g', r', i', z', J, H, K, L', M'
 - 10 Hz full frame, 100 Hz windowed
 - 1.1-4.8µm polarimetry
 - 0.31-1µm IFU

Instrument Concepts Also Considered


Near-IR AO-fed Echelle Spectrometer (NIRES)
 - 1-5µm, AO with NFIRAOS
 - R~20,000 for 1-2.5µm, R~100,000 for 3-5µm
 - Simultaneous 1.5µm@R>20,000
 - 0.004"/pixel
 - >20% throughput


The TMT observatory is designed to support a wide range of different forms of facility class instrumentation. An original suite of instrument concepts was developed and the observatory design was developed around them (see listing of instrument requirements in the TMT Science Requirements Document - SRD). These longstanding ideas for instruments have continued to evolve and new instrument concepts are being actively developed (see a present list on the left). Currently the main instruments planned for operation at first-light are WFOS, MODHIS, and IRIS. Any other facility-instruments planned afterwards are part of the “next-generation” suite of instruments. The prioritization for future instrument capabilities and the resulting strategy or sequence for instrument development is based on community exploration.

To support the exploration of future instrument ideas an extensive investigation of the ability of the observatory to support polarimetric observing modes was carried out. The science limitiations and abilities were explored and it was determined that there are many potential science programs that could be carried out if suitable polarimetric instrumentation is developed even though the fundamental polarimetric precision with TMT is affected by the three mirror design.

In accordance with the Future Instrument Development process, the first set of community explorations were formally started in September, 2017 with a call for TMT Instrumentation White Papers (deadline for submission was March 21, 2018). In addition, the 2017 TMT Science Forum, held in Mysore, India, was dedicated to forming the teams to kick off the concept studies for the next generation of TMT instruments. Some of these teams have existed and been active over the previous few years and their specific instrument concepts were explored at the 2017 TMT Science Forum:

  • A mid-infrared spectra-imager instrument. The current concept is named ‘b-MICHI’ with lead scientist, Chris Packham (,
  • A high-contrast instrument for detecting and characterizing the atmospheres of exoplanets (concept named 'PSI' for Planetary Systems Imager),
  • High-resolution spectrographs in the visible domain (HROS), and near-infrared (NIRES),
  • Multi-object medium-resolution spectrographs in the near-IR such as IRMS and IRMOS.

An outcome of the 2017 Forum was to respond to the call for White Papers on TMT next generation instrumentation, which will lead to launching feasibilities studies (subject to availability of funding) for all concepts ranked as top-priority by the TMT Science Advisory Committee. The list on the left includes a mix of well established instrument concepts as well as several more novel but exciting concepts.

See the informational flyer on Second Generation Instruments.

Future instrument development

The instrument development process

The instrument development process

The TMT instrument development program will ensure the TMT Observatory remains at the forefront of astronomical research over its lifetime with regular augmentation of observatory capabilities that will maintain TMT’s scientific competitiveness. The Instrument Development Office (IDO) will start during early operations and ensure that the First Decade instruments are delivered at two to three year intervals.

An instrument development effort for TMT is, due to its magnitude, an international collaborative effort.

The first community-wide call for instrument white papers took place in October 2017, the detailed definition of the TMT First Decade instruments is currently taking place. Many technical and design activities are underway for PSI, MICHI, and MIRAO. The HROS science team is developing their science cases, science requirements and conducting initial technical studies while the science team behind IRMOS is planning to conduct a science-based trade study to select its final MOS architecture.