First Results with the James Webb Space Telescope (JWST) MIRI instrument

Day: Thursday 22 September
Time: 09:35 - 10:00 CEST
Location: Room Paris South, Level 3, Hall 7, Paris Convention Centre

The James Webb space telescope has been successfully launched on the 25th of December 2021 by an Ariane rocket. With a primary mirror of 6.5m in size, it is the largest telescope in space. The telescope is equipped with four scientific instruments: 3 instruments providing observation in the 0.6 – 5 microns wavelength range: NIRCAM, NIRSPEC and NIRISS and one instrument dedicated to the 5 – 28 microns wavelength range : MIRI. Webb is a NASA flagship mission with participation of Europe through the European Space Agency (ESA) and Canada through the Canadian Space Agency (CSA).

France has been strongly involved in the MIRI instrument. MIRI is an instrument provided by a consortium of laboratories under the leadership of Gillian Wright from the Royal Observatory of Eddinburg. The French contribution has been focused on the imager part of MIRI: MIRIm. Three modes of observations are possible with MIRIm:

  • imaging with a pixel field of view of 0.11 arcsecond, a field of view of 74x113 arcsecond2 and a choice between 9 filters,
  • slit or slitless spectroscopy at low spectral resolution (R =100 at 7 microns) over the 5-11 microns wavelength range, and
  • coronagraphy with a set of 4 quadrant phase masks (first time in space) and a classical Lyot mask.

The instrument is fully commissioned, achieving exquisite image quality and meeting or exceeding the requirements. The first scientific observations have been made to public in July. During our talk at the IAC we will present the French contribution, describe MIRIm, present the performance of the various modes of MIRIm, as well as first scientific observations.



Director of Research, Laboratoire d’Etudes Spatiales et d’Instrumentation en Astrophysique, Paris Observatory


Pierre-Olivier LAGAGE

Senior Astrophysicist, Commissariat à l’Energie Atomique et aux Energies Alternatives (CEA)



Project Manager for French contributions to MIRI (JWST), Centre National d’Etudes Spatiales (CNES)