Status update on the development of METIS, the mid-infrared ELT imager and spectrograph

Abstract

The Mid-Infrared ELT Imager and Spectrograph (METIS) is one of the first generation science instruments on ESO's 39m Extremely Large Telescope (ELT). METIS will provide diffraction-limited imaging and medium resolution slitspectroscopy from 3 -13 microns (L, M, and N bands), as well as high resolution (R ~ 100,000) integral field spectroscopy from 2.9 -5.3 microns. Both imaging and IFU spectroscopy can be combined with coronagraphic techniques. After passing its preliminary design review (PDR) in May 2019, and the final design review (FDR) of its optical system in June 2021, METIS is now preparing for the FDR of its entire system in the fall of 2022, while the procurements of many optical components have already started. First light at the telescope is expected in 2028, after a comprehensive assembly integration and test phase. In this paper we focus mainly on the various design aspects, and present a status update on the final optical and mechanical design of METIS. We describe the conceptual setup of METIS, its key functional components, and the resulting observing modes. Last but not least, we present the expected scientific performance, in terms of sensitivity, adaptive optics, and high contrast imaging performance.

Spectral Imager of the Solar Atmosphere: The First Extreme-Ultraviolet Solar Integral Field Spectrograph Using Slicers

“…Image slicers have been used for ground-based telescopes in recent decades, operating at different spectral ranges from the infrared to UV/visible, for a wide variety of science cases. Some examples are shown in Figure 3 and include the following: VLT CUBES [90], BlueMUSE [91] and MUSE [92]; GTC FRIDA [93]; GNIRS at Gemini North Telescope or ELT HARMONI [94] and METIS [95] for night-time observation. For solar physics, image slicers were first proposed for the integral field spectrograph [96,97] of the European Solar Telescope, which provides optical observations.…”

Mid-Infrared Observations of the Giant Planets

“…Looking even further ahead, the European Southern Observatory's planned 39.3-m Extremely Large Telescope (ELT) first-generation instruments will include the Mid-infrared ELT Imager and Spectrograph (METIS) [303]. METIS promises to provide diffraction-limited imaging and medium resolution slit-spectroscopy from 3 to 13 µm (covering the M and N bands), as well as high resolution (R∼100,000) integral field spectroscopy (IFU) from 2.9 to 5.3 µm [304]. N-band imaging will be capable of an amazing 6.8-mas (milli-arcsecond) angular resolution over a 13.5 × 13.5 field of view (FoV).…”

“…Likewise, the even narrower FoV of the M-band IFU (0.58 × 0.93 ) will be optimal for analyzing small-scale, 5-µm atmospheric features with unprecedented resolution from the ground. With METIS' first light expected in 2028 [304], the complementary capabilities of MIMIZUKU, VISIR, and METIS promise exciting advances in mid-infrared observations from the ground over the next decade.…”

Understanding the role of additive manufacturing in the development of astronomical hardware

“…The goal of this case study was to explore the design freedom and challenges of using AM to create lightweight opto-mechanical structures for future instruments related to the next generation of 30 m class telescopes: the ELT, the Giant Magellan Telescope and the Thirty Meter Telescope. The specific case study focussed on a three mirror anastigmat (TMA) assembly within the mid-infrared ELT imager and spectrograph 25 (METIS) instrument. The objectives in using AM for this case were:…”