text: MIRI Coronagraphic Performance (OLD) - JWST User Documentation
  MIRI Coronagraphic Performance (OLD)
  The performance of the MIRI flight coronagraphs was tested and verified in the flight model (FM) imager prior to its delivery to be integrated with the full MIRI Optics Module (OM).
  The performance of the MIRI flight coronagraphs was verified in the flight model (FM) imager prior to its delivery to be integrated with the full MIRI Optics Module (OM) (Ronayette et al. 2010). A broader discussion on JWST coronagraphy discusses terminology and implementation strategies.
  The test arrangement consists of a warm source outside the cryostat with heavy filtering to block room-temperature thermal radiation. A 30 μm diameter pinhole source (much smaller than the FWHM of the diffraction pattern) in the external apparatus was scanned in a raster pattern to measure the response of the coronagraphs.
  Sample images at 11.40 μm: left without the coronagraph, right with it. The field-of-view is 8.36′′ (76 detector pixels) and the color scale indicates the contrast with respect to the PSF maximum. The level of the coronagraphic image is close to the background noise and the central residual is attributed to the size of the source, which is not perfectly point-like. The faint extended residual in the image to the right is due to local heating of the surroundings of the pinhole infrared source, which is not rejected by the coronagraph and places an artificial floor on its contrast performance.
  Boccaletti, A., et al. "The Mid-Infrared Instrument for the James Webb Space Telescope, V: Predicted Performance of the MIRI Coronagraphs." 2015, PASP, 127, 633.
  Ronayette, S., et al. 2010, " Performance verification of the MIRI imager flight model at CEA," SPIE, 7731, 3.