Final design of VISIR: the mid-infrared imager and spectrometer for the VLT

In this paper, we present the status of VISIR, the mid-IR instrument to be installed in 2001 at the Cassegrain focus of YEPUN, the telescope unit number 4 of the European Very Large Telescope program. This cryogenic instrument, optimized for both mid-IR atmospheric windows, combines imaging capabilities over a field up to about 1 arcmin at the diffraction limit of the telescope, and long-slit grating spectroscopy capabilities with various spectral resolution up to 25000 at 10 micrometers at 20 micrometers . The contrast to design and build VISIR was signed in November 1996 between the European Southern Observatory and French-Dutch consortium of institutes led by Service d'Astrophysique of Commissariat a l'Energie Atomique. A key step in the project has been passed in 1999: the final design review. The instrument is now in the manufacture phase. Several subsystems have already been built and tested. The integration of the whole instrument is scheduled to start in December 2000.