Astronomical optical interferometry:: an assessment

Optical interferometry (visible and infrared) becomes a powerful tool for astronomy, with the commissioning in 2001 of two arrays: the Very Large Telescope and the Keek. A survey of the existing interferometers is given, as well as an overview of the scientific achievements of their operation during the last decade, showing that most of the observational difficulties: are now solved. Although these results mainly deal with stellar physics, the opening of new domains (extra-solar planets, active galactic nuclei) is imminent. Beyond this, new concepts are already proposed which will lead to an increase of resolution, imaging capabilities or spectral range. (C) 2001 Academie des sciences/Editions scientifiques et medicales Elsevier SAS.