The Very Large Telescope Interferometer: Current facility and prospects

The Very Large Telescope Interferometer on Cerro Paranal in Northern Chile is one of the largest optical facilities used in astronomy. It can combine two or three of the four 8.2 m and four movable 1.8 m telescopes, which span baselines between 8 and 202 m. Observations are carried out in the near- and mid-infrared, covering the wavelength range from 1 to 10 μm. In this paper, we describe the status of the interferometric facility at the end of 2006 and provide an overview about the challenges encountered when operating this optical interferometer.