Swiss 1.2-metre Leonhard Euler Telescope


Leonhard Euler Telescope
The enclosure of the Leonhard Euler Telescope with the higher situated New Technology Telescope in the background
Alternative namesSwiss 1.2-m Leonhard Euler Telescope Edit this at Wikidata
Named afterLeonhard Euler Edit this on Wikidata
Part ofLa Silla Observatory Edit this on Wikidata
Location(s)Norte Chico in Chile
Coordinates29°15′34″S 70°43′59″W / 29.2594°S 70.7331°W / -29.2594; -70.7331Coordinates: 29°15′34″S 70°43′59″W / 29.2594°S 70.7331°W / -29.2594; -70.7331 Edit this at Wikidata
OrganizationGeneva Observatory Edit this on Wikidata
First light12 April 1998 Edit this on Wikidata
Telescope stylereflecting telescope Edit this on Wikidata
Diameter1.2 m (3 ft 11 in) Edit this at Wikidata
Swiss 1.2-metre Leonhard Euler Telescope is located in Chile
Swiss 1.2-metre Leonhard Euler Telescope
Location of Swiss 1.2-metre Leonhard Euler Telescope
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Leonhard Euler Telescope, or the Swiss EULER Telescope, is a national, fully automatic 1.2-metre (47 in) reflecting telescope, built and operated by the Geneva Observatory. It is located at an altitude of 2,375 m (7,792 ft) at ESO's La Silla Observatory site in the Chilean Norte Chico region, about 460 kilometers north of Santiago de Chile. The telescope, which saw its first light on 12 April 1998, is named after Swiss mathematician Leonhard Paul Euler.[1][2]

The Euler telescope uses the CORALIE instrument to search for exoplanets. In addition, the telescope uses the multi-purpose EulerCam (ecam), a high precision photometry instrument, and a smaller, piggyback mounted telescope, called "Pisco".[2] Its first discovery was a planet in orbit around Gliese 86, determined to be a hot Jupiter with an orbital period of only 15.8 earth days and about four times the mass of Jupiter.[3] Since then, many other exoplanets have been discovered or examined in follow-up observations.

Together with the Mercator Telescope, Euler was part of the Southern Sky extrasolar Planet search Programme, which has discovered numerous extrasolar planets.[4] It has also been frequently employed for follow-up characterization to determine the mass of exoplanets discovered by the Wide Angle Search for Planets, SuperWASP.[5]


The CORALIE spectrograph is an echelle type spectrograph used for astronomy and was commissioned at the Euler Telescope in April 1998. The instrument performs doppler spectroscopy, that is it measures the Doppler effect on a star's electromagnetic spectrum caused by the gravitational tug of an exoplanet orbiting around it.[6][7] The spectrograph participates in the Southern Sky extrasolar Planet search Programme.

Doppler spectroscopy, also known as "radial velocity" or "wobble" method, is an indirect detection method as it only observes the star's spectrum and not the planet itself. It differs from the transit method used by the space-based Kepler mission and ground-based SuperWASP and Next-Generation Transit Survey and can therefore be complementary to their observations. This is because the size of an exoplanet can be estimated using the transit method, while Doppler spectroscopy is used to estimate its mass. By combining the measured size and mass from both methods, it can be determined whether the observed exoplanet is gaseous or rocky.

The ELODIE spectrograph was a device similar to CORALIE[8]


The resolution of CORALIE is fixed at R = 50,000 with a 3 pixel sampling. The detector CCD is 2k X 2k with a 15 micrometer pixel size.

Discovered exoplanets

Five planetary object have been discovered using CORALIE along with several confirmations of discoveries by other programs.

Planet Announced in Refs
Gliese 86 b 1998 [6]
HD 75289b 1999 [9]
HD 130322 b 1999 [9]
HD 192263b 1999 [10][11]
GJ 3021b 2000 [12]



Timelapse video of Euler and the NTT observing the night sky

See also


  1. ^ "Swiss 1.2-metre Leonhard Euler Telescope". ESO. Retrieved 10 September 2015.
  2. ^ a b "EULER". Exoplanets. Switzerland: Université de Genève. Retrieved 10 September 2015.
  3. ^ Queloz, D.; Mayor, M.; Weber, L.; Blecha, A.; et al. (1999). "A planet orbiting the star Gliese 86". arXiv:astro-ph/9910223.
  4. ^ "Southern Sky extrasolar Planet search Programme".
  5. ^ Queloz, D.; Anderson, D. R.; Collier Cameron, A.; Gillon, M.; et al. (2010). "WASP-8b: a retrograde transiting planet in a multiple system". Astronomy and Astrophysics. 517: L1. arXiv:1006.5089. Bibcode:2010A&A...517L...1Q. doi:10.1051/0004-6361/201014768. S2CID 35774603.
  6. ^ a b Queloz, D.; Mayor, M.; Weber, L.; Blécha, A.; et al. (2000). "The CORALIE survey for southern extra-solar planets. I. A planet orbiting the star Gliese 86". Astronomy and Astrophysics. 354: 99–102. Bibcode:2000A&A...354...99Q.
  7. ^ ESO publication, D. Queloz and M. Mayor, From CORALIE to HARPS, September 2001
  8. ^ "Extrasolar Planet Search Programme at Haute-Provence Observatory". Observatory of Geneva. Retrieved 17 August 2015.
  9. ^ a b Udry; Mayor, M.; Naef, D.; Pepe, F.; et al. (2000). "The CORALIE survey for southern extra-solar planets II. The short-period planetary companions to HD 75289 and HD 130322". Astronomy and Astrophysics. 356: 590–598. Bibcode:2000A&A...356..590U.
  10. ^ Santos, N.; Udry, S.; Mayor, M.; Naef, D.; et al. (2003). "The CORALIE survey for southern extra-solar planets XI. The return of the giant planet orbiting HD192263". Astronomy and Astrophysics. 406 (1): 373–381. arXiv:astro-ph/0305434. Bibcode:2003A&A...406..373S. doi:10.1051/0004-6361:20030776. S2CID 16247618.
  11. ^ Santos, N.; Mayor, M.; Naef, D.; Pepe, F.; et al. (2000). "The CORALIE survey for southern extra-solar planets III. A giant planet in orbit around HD 192263". Astronomy and Astrophysics. 356: 599–602. Bibcode:2000A&A...356..599S.
  12. ^ Naef, D.; Mayor, M.; Pepe, F.; Queloz, D.; et al. (2001). "The CORALIE survey for southern extrasolar planets V: 3 new extrasolar planets". Astronomy and Astrophysics. 375 (1): 205–218. arXiv:astro-ph/0106255. Bibcode:2001A&A...375..205N. doi:10.1051/0004-6361:20010841. S2CID 16606841.

External links

  • ESO La Silla 1.2m Leonhard Euler Telescope
  • Southern Sky extrasolar Planet search Programme
  • The CORALIE survey for southern extrasolar planets
  • University of Geneva – The Geneva Observatory
  • /Euler
  • ESO press release: 4 May 2000