European Southern Observatory (ESO) - Instruments at La Silla, Instruments at Paranal

An agency of eight member states founded in 1962 to operate a European astronomical observatory in the S hemisphere. It is a world-class observatory with a number of optical telescopes, including the 3·6 m aperture at La Silla, Chile (2430 m/7972 ft), and a share in a sub-millimetre telescope. Construction is under way on Cerro Paranal, Chile (2635 m/8645 ft) of an array of four 8·2 m aperture telescopes which can be combined to form an effective 16 m telescope (Very Large Telescope, or VLT). The first telescope came into operation in 1998, and the fourth was completed in 2000; they have been given names in a local indigenous language, Mapuche: Antu (Sun), Kueyen (Moon), Melipal (Southern Cross), and Yepun (Venus). The European headquarters is at Garching, Munich, Germany; this also houses the Space Telescope European Co-ordinating Facility.

The European Southern Observatory (ESO, also more formally the European Organisation for Astronomical Research in the Southern Hemisphere) is an intergovernmental research organisation for astronomy, composed and supported by eleven countries from the European Union plus Switzerland. Created in 1962, it is famous for building and operating some of the largest and most technologically advanced telescopes in the world, such as the New Technology Telescope (NTT), which was one of the telescopes which pioneered active optics technology, and more recently the VLT (Very Large Telescope), consisting of four 8-meter class telescopes. ESO operates three major observatories in Chile's Atacama desert:

La Silla Observatory Paranal Observatory, which includes the Very Large Telescope Llano de Chajnantor Observatory, which will host submillimetre telescopes, and is operated in collaboration with organisations in the USA, Canada and Chile.

One of the most ambitious ESO projects is the Overwhelmingly Large Telescope (OWL). If built, it will be the largest optical telescope in the world.

Instruments at La Silla

Of the eighteen telescopes at La Silla Observatory, three are operated by ESO for use by the ESO astronomical community:

2.2 m telescope

This telescope is loaned from the Max-Planck-Gesellschaft.

3.6 m telescope

A conventionally designed horseshoe mount telescope, this is mostly instrumented for infrared spectroscopy.

New Technology Telescope (NTT)

Although the NTT is almost the same size as the 3.6 m telescope, the use of active optics makes it a higher resolution instrument.

Instruments at Paranal

The Very Large Telescope (VLT) is the main instrument, composed of four near-identical 8.2 m telescopes. In addition the four main telescopes can combine their light to make a fifth instrument, the VLTI, Very Large Telescope Interferometer. Four auxiliary telescopes of 1.8 m each are being added to the VLTI to make it available when the main telescopes are being used for other projects.

The site also houses the 2.5 m VLT Survey Telescope and 4 m VISTA survey telescope with wider fields of view for surveying large areas of sky uniformly.