Astronomical optical interferometry: an assessment

Optical interferometry (visible and infrared) becomes a powerful tool for a stronomy, with the commissioning in 2001 of two arrays: the Very Large Tele scope and the Keek. A survey of the existing interferometers is given, as w ell 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 op ening of new domains (extra-solar planets, active galactic nuclei) is immin ent. Beyond this, new concepts are already proposed which will lead to an i ncrease of resolution, imaging capabilities or spectral range. (C) 2001 Aca demie des sciences/Editions scientifiques et medicales Elsevier SAS.