Mid-Infrared Instrumentation for the European Extremely Large Telescope

TL;DR

MIDIR is a proposed mid-infrared instrument for the E-ELT, aiming for diffraction-limited imaging and spectroscopy from 3 to 20 microns, with a focus on adaptive optics and cryogenic cooling.

Contribution

This paper provides an overview of MIDIR's science goals, design considerations, and how telescope design influences its requirements.

Findings

MIDIR's design emphasizes diffraction-limited performance across 3-20 microns.

Cryogenic cooling is identified as critical for optimal IR performance.

Design choices of the E-ELT impact MIDIR's instrument requirements.

Abstract

MIDIR is the proposed thermal/mid-IR imager and spectrograph for the European Extremely Large Telescope (E-ELT). It will cover the wavelength range of 3 to at least 20 microns. Designed for diffraction-limited performance over the entire wavelength range, MIDIR will require an adaptive optics system; a cryogenically cooled system could offer optimal performance in the IR, and this is a critical aspect of the instrument design. We present here an overview of the project, including a discussion of MIDIR's science goals and a comparison with other infrared (IR) facilities planned in the next decade; top level requirements derived from these goals are outlined. We describe the optical and mechanical design work carried out in the context of a conceptual design study, and discuss some important issues to emerge from this work, related to the design, operation and calibration of the instrument. The impact of telescope optical design choices on the requirements for the MIDIR instrument is demonstrated.