Very Large Telescope

The world's most advanced visible-light astronomical observatory


LIVE panoramic image of Paranal ()

The Very Large Telescope array (VLT) is the flagship facility for European ground-based astronomy at the beginning of the third Millennium. It is the world's most advanced optical instrument, consisting of four Unit Telescopes with main mirrors of 8.2m diameter and four movable 1.8m diameter Auxiliary Telescopes. The telescopes can work together, to form a giant ‘interferometer’, the ESO Very Large Telescope Interferometer, allowing astronomers to see details up to 25 times finer than with the individual telescopes. The light beams are combined in the VLTI using a complex system of mirrors in underground tunnels where the light paths must be kept equal to distances less than 1/1000 mm over a hundred metres. With this kind of precision the VLTI can reconstruct images with an angular resolution of milliarcseconds, equivalent to distinguishing the two headlights of a car at the distance of the Moon.

The 8.2m diameter Unit Telescopes can also be used individually. With one such telescope, images of celestial objects as faint as magnitude 30 can be obtained in a one-hour exposure. This corresponds to seeing objects that are four billion (four thousand million) times fainter than what can be seen with the unaided eye.

The large telescopes are named Antu, Kueyen, Melipal and Yepun.

LIVE webcam


LIVE image of MELIPAL, also known as UT3 ()

A Tour at Paranal Observatory

Virtual Tour at ESO Very Large Telescope

Click on the image to take a Virtual Tour in and nearby the VLT.



Visit Paranal Observatory

Telescopes and Instruments

The VLT instrumentation programme is the most ambitious programme ever conceived for a single observatory. It includes large-field imagers, adaptive optics corrected cameras and spectrographs, as well as high-resolution and multi-object spectrographs and covers a broad spectral region, from deep ultraviolet (300 nm) to mid-infrared (24 µm) wavelengths.

The Unit Telescopes

The 8.2m diameter telescopes are housed in compact, thermally controlled buildings, which rotate synchronously with the telescopes. This design minimises any adverse effects on the observing conditions, for instance from air turbulence in the telescope tube, which might otherwise occur due to variations in the temperature and wind flow. The first of the Unit Telescopes, 'Antu', went into routine scientific operations on 1 April 1999. Today, all four Unit Telescopes and all four Auxiliary Telescopes are operational.

The Auxiliary Telescopes

Although the four 8.2-metre Unit Telescopes can be combined in the VLTI, they are mostly used for individual observations and are only available for interferometric observations for a limited number of nights every year. But four smaller, dedicated 1.8-metre Auxiliary Telescopes (ATs) are available to allow the VLTI to operate every night.

More information is available on this link

Science with the Very Large Telescope

The VLT has made an undisputed impact on observational astronomy. It is the most productive individual ground-based facility, and results from the VLT have led to the publication of an average of more than one peer-reviewed scientific paper per day. VLT contributes greatly to making ESO the most productive ground-based observatory in the world. The VLT has stimulated a new age of discoveries, with several notable scientific firsts, including the first image of an extrasolar planet (eso0428), tracking individual stars moving around the supermassive black hole at the centre of the Milky Way (eso0846), and observing the afterglow of the furthest known Gamma-Ray Burst.

Science goals

General purpose large aperture optical/infrared telescope. Applications include high redshift galaxies, star formation, exoplanets and protoplanetary systems.

More about Science with the VLT

More about the Very Large Telescope

  • More interesting facts are available on the FAQs page
  • More images and videos are available in the ESO multimedia archive
  • Read more on about this telescope on the VLT Handout in PDF format
  • For Scientists: for more detailed information, please see our technical pages
  • More detailed background and technical information is provided in the VLT Whitebook


The VLT hotel, the Residencia, is an award-winning building, and served as a backdrop for part of the James Bond movie Quantum of Solace.

The VLT Trailer

Download the VLT trailer in the video archive.



Name: Very Large Telescope
Site: Cerro Paranal
Altitude: 2635 m
Enclosure: Compact optimised cylindrical enclosure
Type: Optical/infrared, with interferometry
Optical design: Ritchey-Chrétien reflector
Diameter. Primary M1: 8.20 m
Material. Primary M1: ZeroDur
Diameter. Secondary M2: 0.94 m
Material. Secondary M2: Beryllium
Diameter. Tertiary M3: 1.242 x 0.866 m (elliptical flat)
Mount: Alt-Azimuth mount
First Light date: UT1, Antu: 25 May 1998
UT2, Kueyen: 1 March 1999
UT3, Melipal: 26 Jan 2000
UT4, Yepun: 4 September 2000
Active Optics: Yes
Adaptive Optics: UT4: Laser Guide Star + NACO
Interferometry: UT maximum 130 m baseline
Images taken with the VLT: Link
Images of the VLT: Link
Press Releases with the VLT: Link



The VLT on Google map


View Larger Map

Download the 3D models of the telescopes and see them in Google earth (kmz file, 4.8MB)