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Overview of Michelle's Capabilities

Michelle is a mid-infrared (7-26 micron) imager and spectrometer, formerly in use at UKIRT but now on long-term loan at Gemini. Michelle is available for imaging and spectroscopy with all of its gratings and its echelle. Imaging polarimetry is now also supported.

Michelle's detector is a Si:As IBC array with a format of 320x240 pixels. When configured in its imaging mode, Michelle has a 0.1005 arcsec/pixel plate scale and critically samples the diffraction limited mid-infrared Gemini PSF. When configured as a long slit spectrometer, Michelle has a plate scale of 0.183 arcsec/pixel and employs five gratings covering a range of wavelengths and resolutions. With the lowest resolution gratings, spectra of the entire 8-13 micron or 16-25 micron windows can be recorded in a single exposure. At medium and high resolutions the detailed profiles of dust and hydrocarbon emission and absorption features can be observed as well as the velocity profiles of broad lines. Michelle's echelle provides velocity-resolved observations of narrow emission lines. Michelle provides background limited performance in all of these modes except, in some cases, at the highest spectral resolution.

The Instrument Scientist for Michelle is Marie Lemoine-Busserolle.


  • There have been recent improvements in the Michelle image quality. A detailed description of the current PSF characteristics of Michelle is available.
  •  Spectral polarimetry mode will not be commissioned in 2008B or 2009A.
  •  There is a dead channel in Michelle, which has some implications for imaging and spectroscopy.

See the Status and Availability page for news, including information about improvements to image quality. A document describing the effect of observing conditions on mid-IR data is now available (Mason et al., SPIE, vol. 7016, page 63, 2008).

Michelle Science Highlights

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How to Use These Pages

The Gemini instrument pages first give the status of the instrument and its availability in the next semester. The information is then organized initially by instrument mode, followed by technical information necessary for writing a proposal and detailed observation planning, and then content relevant to reducing and interpreting data.

  • Status and Availability: Modes available in the current and upcoming semesters; links to news items
  • Imaging: Components used in imaging mode, and guidance on how best to use the instrument in this mode.
  • Spectroscopy: Components used in spectroscopy mode, and guidance on how best to use the instrument in this mode.
  • Imaging Polarimetry: Components used in imaging polarimetry mode, and guidance on how best to use the instrument in this mode.
  • Sensitivity and Overheads: Sensitivity tables, integration time calculator, and details of observing overheads.
  • Guiding Options: Guiding considerations, and wavefront sensors available for use with Michelle.
  • Calibration: How to calibrate Michelle observations.
  • Observation Preparation: How to configure Michelle in the Observing Tool.
  • Data Format and Reduction: Examples of Michelle data and links to data reduction resources.
  • References: Michelle design documents and references.

Please see also the Mid-IR Resources section, which contains generic information about observing in the mid-IR, as well as details about calibrations, standard stars etc. that apply to Michelle, T-ReCS and TEXES.