The Mid-infrared ELT Imager and Spectrograph (METIS) is one of the scientific instruments for the ELT. The Common Fore Optics (CFO) is the first set of optics and mechanisms within the cryogenic instrument. A key element of the CFO is the Pupil Stabilization Mechanism (PSM), a tip/tilt mirror used for periodic adjustments of the pupil alignment during observations. The design challenges for the PSM involved achieving the required stability, resolution, and a sufficient stroke range/hold power while operating within the stringent requirements of the CFO. The design development lead to a monolithic design and integrated flexures driven by actuators with an integrated closed loop optical encoder.
Moving into the era of Extremely Large Telescopes (ELT), the size and complexity of the instruments increased significantly while constraints and requirements remain tight. NOVA follows a monolithic design strategy, meaning that the size of individual components scales with the size of the instrument. To enable the manufacturing and assembly of the largest components at the required precision, NOVA has invested in a new facility for ELT-era instrumentation: NOVA Manufacturing and Assembly of eXtreme instrumentation (MAX). Here we introduce the capabilities of NOVA MAX, which includes a 5-axis CNC milling machine and a Coordinate-Measuring Machine (CMM) in a temperature-stabilized environment. The CMM is located in a cleanroom with temperature variations < 0.5K/24 hours, enabling micron-level verification and fine-tuning during assembly. This unique assembly facility is crucial when producing large size one-off instruments. We report on, amongst others, the tolerances, dimensions, and loads that can be achieved with both machines and present the first components that have been manufactured for the METIS and MICADO ELT instruments.
MICADO is a first light instrument for the Extremely Large Telescope (ELT), set to start operating later this decade. It will provide diffraction limited imaging, astrometry, high contrast imaging, and long slit spectroscopy at near-infrared wavelengths. During the initial phase operations, adaptive optics (AO) correction will be provided by its own natural guide star wavefront sensor. In its final configuration, that AO system will be retained and complemented by the laser guide star multi-conjugate adaptive optics module MORFEO (formerly known as MAORY). Among many other things, MICADO will study exoplanets, distant galaxies and stars, and investigate black holes, such as Sagittarius A* at the centre of the Milky Way. After their final design phase, most components of MICADO have moved on to the manufacturing and assembly phase. Here we summarize the final design of the instrument and provide an overview about its current manufacturing status and the timeline. Some lessons learned from the final design review process will be presented in order to help future instrumentation projects to cope with the challenges arising from the substantial differences between projects for 8-10m class telescopes (e.g. ESO’s VLT) and the next generation Extremely Large Telescopes (e.g. ESO’s ELT). Finally, MICADO's expected performance will be discussed in the context of the current landscape of astronomical observatories and instruments. For instance, MICADO will have similar sensitivity as the James Webb Space Telescope (JWST), but with six times the spatial resolution.
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