ESO 3.6 m Telescope
|ESO 3.6 meter Telescope|
|Organization||European Southern Observatory|
|Location||La Silla Observatory, Chile|
|Coordinates||70° 43' 54.1" W -29° 15' 39.5" S (WGS84)|
|Altitude||2400 m (7874 ft)|
|Built||1976 first light
1977 full operations
|Diameter||3.566 m (140″)|
|Angular resolution||0.2 arcsec at Zenith|
|Collecting area||8.8564 m2|
|Focal length||f/8 (HARPS)|
The ESO 3.6 m Telescope is an optical reflecting telescope run by the European Southern Observatory at La Silla Observatory, Chile since 1977, with a clear aperture of about 3.6 meters (140 in.) and 8.6 m2 area. It received an overhaul in 1999 and a new secondary in 2004. It was one of the largest optical telescopes in the world when it was completed in the late 1970s, and has supported many advanced optical and scientific achievements. It presented one of the first Adaptive Optics system available to the astronomical community, ADONIS: ADaptive Optics Near Infrared System in the 1980s.
Since April 2008, the only instrument on the ESO 3.6m telescope is HARPS, the High Accuracy Radial Velocity Planet Searcher. HARPS is a fibre-fed high resolution echelle spectrograph dedicated to the discovery of extrasolar planets. Other instruments on the telescope, now decommissioned, include:
- CES: A spectrograph providing a resolving power of up to 235,000 in the 346 - 1028 nm region.
- EFOSC2: The ESO Faint Object Spectrograph and Camera (v.2) to give its full name, is a very versatile instrument for low resolution spectroscopy and imaging.
- TIMMI-2 Thermal Infrared MultiMode Instrument dedicated to the 3 micron to 25 micron
- ADONIS, an acronym for ADaptive Optics Near Infrared System, was a second-generation adaptive optics system for the astronomical community. More than 40 peer-reviewed scientific articles were published based on this instrument data. ADONIS is the final version of diverse Adaptive Optics (AO) prototypes named Come-on and Come-on +. It was offered in its final version in October 1996 as an official ESO instrument, then decommissioned in 2001. ADONIS was the first AO system offered to a large community of astronomers.
 Recent scientific achievements
The ESO 3.6m telescope has made several scientific discoveries since it saw first light. Recent astronomical achievements were made possible by HARPS, a "top-class" instrument. This include finding the lightest exoplanet known at the time of discovery in, Gliese 581e, with only twice the mass of the Earth, and the richest planetary system known at the time, with up to seven planets orbiting a Sun-like star.
The telescope was also involved in solving a decades-old mystery regarding the mass of Cepheid variable stars. By using the HARPS instrument, astronomers detected for the first time a double star where a pulsating Cepheid variable and another star pass in front of one another, which allows to measure the mass of the Cepheid. The study concluded that the mass prediction coming from the theory of stellar pulsation was correct while the value calculated was at odds with the theory of stellar evolution.
The discovery of the extrasolar planet Gliese 581 c by the team of Stéphane Udry at University of Geneva's Observatory in Switzerland was announced on April 24, 2007. The team used the HARPS instrument (an echelle spectrograph) on the European Southern Observatory ESO 3.6 m Telescope in La Silla, Chile, and employed the radial velocity technique to identify the planet's influence on the star.
 Contemporaries on commissioning
In the heat of a Cold War, the ESO 3.6 m took its place among giant eyes old and new.
Largest telescopes in 1976:
Special Astrophysical Obs
|26 m2||2070 m
|20 m2||1713 m
|1949||George Ellery Hale|
Kitt Peak National Obs.
|10 m2||2120 m
|4||CTIO 4m/Blanco Telescope
|10 m2||2200 m
Siding Spring Obs.
|6||ESO 3.6 Telescope
ESO La Silla Obs.
|8.8 m2||2400 m
 The telescope and site
 Images from telescope
 See also
- List of largest optical reflecting telescopes
- List of largest optical telescopes in the 20th century
- The ESO 3.6 meter Telescope
- "Telescopes and Instrumentation, the ESO 3.6-metre Telescope". Retrieved 2011-05-02 (table on the right of the page).
- B. Betts - First Planet Discovered in Alpha Centauri System - TPS
- "The ESO 3.6m Telescope". Retrieved 2011-05-26.
- Jack B. Zirker (2005). An acre of glass: a history and forecast of the telescope. JHU Press. p. 204. ISBN 978-0-8018-8234-0. Unknown parameter
- ADS query results for "ADONIS"
- Gérard Rousset and Jean-Luc Beuzit (1999). "The COME-ON/ADONIS systems". In François Roddier. Adaptive optics in astronomy. Cambridge University Press. pp. 171 et seq. ISBN 978-0-521-55375-9. Unknown parameter
- "Lightest exoplanet yet discovered". ESO. 2009-04-21. Retrieved 2011-05-26.
- "Richest Planetary System Discovered". ESO. 2010-08-24. Retrieved 2011-05-26.
- "Pulsating Star Mystery Solved". ESO. 2010-11-24. Retrieved 2011-05-26.
- Than, Ker (2007-04-24). "Major Discovery: New Planet Could Harbor Water and Life". space.com. Retrieved 2007-04-29.
- Than, Ker (2007-02-24). "Planet Hunters Edge Closer to Their Holy Grail". space.com. Retrieved 2007-04-29.
- "32 planets discovered outside solar system - CNN.com". CNN. 19 October 2009. Retrieved 4 May 2010.
- 50 new exoplanets discovered by HARPS
- "Three Very Different Telescopes at La Silla". ESO Picture of the Week. Retrieved 8 May 2012.