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The design is showing the Nasmyth platforms (in blue) and two of our early light instruments. The TMT Wide Field Optical Spectrometer (WFOS) is located on the right platform while the Adaptive Optics system (NFIRAOS) plus the InfraRed Imaging Spectrograph (IRIS) are located on the left platform.

A rendering of the Wide-Field Optical Spectrometer (WFOS) Instrument shown in-situ on the TMT Nasmyth Platform - WFOS is a wide field, seeing limited multi-object optical spectrometer and imager. Light from the TMT Tertiary Mirror (M3) is delivered to the WFOS Atmospheric Dispersion Corrector (ADC). The new instrument layout is optimized to be compact.

The WFOS design now features a vertical orientation that enables the instrument to be gravity invariant as it de-rotates the field during observations.

Excerpt from a Mechanical Interface Control Document showing where sonic anemometers (wind speed sensors) will be located on the telescope structure. The telescope-mounted sensors and sensor stations are identified in the Space Envelope drawings

Diagram of the CRYO space envelopes layout (in blue) on the Nasmyth platforms. CRYO will provide liquid nitrogen cooling to first-light instruments.

First TMT M1 Metrology Frame Inspection The metrology frame, sitting on one TMT fixed frame, is being tested using advanced metrology system (pictured on the right) at TMT’s technical lab in Monrovia, April 2020.

During installation of the TMT telescope, metrology frames will be used for initial alignment of TMT Primary Mirror segments.

The TMT design utilizes a calotte-style enclosure, which minimizes the size and footprint of the facility, while allowing full movement of the telescope and optical systems.

Major components of TMT Enclosure

The TMT Enclosure System is a dome structure housing the telescope. The three principal enclosure moving components are the rotating base, cap and shutter structures. Combined rotation of the rotating base and cap provides a range of required azimuth and zenith angles. The shutter is a rotating structure enabling opening and closing of the telescope aperture.

Fabricated by TMT-Japan, MSIT recreates a subset – approximately 1/70th - of the TMT primary mirror cell, and the segments it carries accurately recreate the unique hexagonal forms of the seven segments that will exist in the telescope in the same positions. Mirror segments in TMT are of 82 types – each one very slightly different – arranged in six identical sectors. MSIT contains segments from sectors D and E of the primary mirror.