The Very Large Telescope Interferometer

The Very Large Telescope Interferometer (VLTI) consists in the coherent combination of the four VLT Unit Telescopes and of the four moveable 1.8m Auxiliary Telescopes. Once fully operational, the VLTI will provide both a high sensitivity as well as milli-arcsec angular resolution using baselines of up to 200m length.

General Description

The four 8.2-m Unit Telescopes (UTs) and the four 1.8-m Auxiliary Telescopes (ATs) constitute the light collecting elements of the VLTI. The UTs are set on fixed locations while the ATs can be relocated on 30 different stations. The telescopes can be combined in groups of two or three. After the light beams have passed through a complex system of mirrors and the Delay lines, the combination at near- and mid-infrared is performed by the instruments AMBER and MIDI. A complex and high performance dual-feed system PRIMA that allows Phase Referenced Imaging and Micro Arcsecond Astrometry on the VLTI will be available soon.

Due to its characteristics, the VLTI has become a very attractive means for scientific research on various objects like many stars in the solar neighborhood or extragalactic objects such as active galactic nuclei.


28/08/2014: IMPORTANT according to the P95 Call For Proposal "Starting in March 2015 and during Period 95, the laboratory will undergo major modifica- tions in view of the arrival of the 2nd generation instruments GRAVITY and MATISSE as well as ESPRESSO, which will go in the nearby combined-coud ́e laboratory. As a conse- quence, MIDI will be decommissioned in March 2015, during Period 94, and AMBER and the Visitor Instrument, PIONIER, are not offered in Period 95. AMBER and PIONIER will be offered again in Period 96. "

Stay informed about the latest ESO news: ESO Top News- RSS .