The science case for METIS dictates the following key requirements for the instrument design:
- Diffraction-limited imaging at 3-19 microns with a field of view of approximately 11 x 11". The imager also includes low/medium resolution slit spectroscopy as well as coronagraphy for high contrast imaging.
- An IFU-fed high-resolution spectrograph in L and M bands with a field of view of 0.5 square arcseconds and spectral resolving power of ~100,000, including a mode with extended instantaneous wavelength coverage (N-band under study).
- Possibility to add a coronagraph in the fore-optics; opening up coronagraphy with the IFU's
The instrument consists of two separate units, one for the imager and another for the spectrograph, and is entirely encased in a cryostat to maintain the stable low temperatures required for good performance at mid-infrared wavelengths. To achieve diffraction limited performance, METIS will use adaptive optics correction to compensate for atmospheric turbulence. The instrument will be able to observe with natural guide stars and eventually with laser guide stars.
See the image gallery for views of the instrument.