The Mid-Infrared Instrument for the James Webb Space Telescope, III: MIRIM, The MIRI Imager

TL;DR

The paper details the design, testing, and operational considerations of the MIRIM, the imaging module of the MIRI instrument on the James Webb Space Telescope, covering its optical, mechanical, and performance aspects.

Contribution

It provides a comprehensive description of MIRIM's design, testing results, and operational procedures, advancing the understanding of infrared imaging capabilities on JWST.

Findings

Test data confirms compliance with design requirements

Instrument achieves broad-band imaging in 5-27 microns

Operational procedures enable optimal scientific use

Abstract

In this article, we describe the MIRI Imager module (MIRIM), which provides broad-band imaging in the 5 - 27 microns wavelength range for the James Webb Space Telescope. The imager has a 0"11 pixel scale and a total unobstructed view of 74"x113". The remainder of its nominal 113"x113" field is occupied by the coronagraphs and the low resolution spectrometer. We present the instrument optical and mechanical design. We show that the test data, as measured during the test campaigns undertaken at CEA-Saclay, at the Rutherford Appleton Laboratory, and at the NASA Goddard Space Flight Center, indicate that the instrument complies with its design requirements and goals. We also discuss the operational requirements (multiple dithers and exposures) needed for optimal scientific utilization of the MIRIM.