Interferometric observation at MID-infrared wave-lengths with MIDI

MIDI, the MID-Infrared Interferometric Instrument for ESO's Very Large Telescope Interferometer (VLTI), will be the first instrument for combining mid-infrared light directly in order to obtain angular resolution up to 10 mas ( assuming a 200 m baseline) in a wavelength range from 8 to 13 mum. Currently in the phase of commissioning at Paranal, the start of its scientific operation is expected for summer 2003. Direct interferometry at thermal infrared wavelengths demands special requirements on the instrument and also on the procedures of preparation of data reduction. Hereafter MIDI's different observing modes are described and an example for an interferometric observation is given.