Gran Telescopio Canarias

Gran Telescopio Canarias

Gran Telescopio Canarias, 2008
Organisation Instituto de Astrofísica de Canarias
University of Florida
National Autonomous University of Mexico
Location(s) Roque de los Muchachos Observatory, La Palma, Spain
Coordinates 28°45′23.8″N 17°53′31.3″W / 28.756611°N 17.892028°W / 28.756611; -17.892028Coordinates: 28°45′23.8″N 17°53′31.3″W / 28.756611°N 17.892028°W / 28.756611; -17.892028
Altitude 2,267 m (7,438 ft)[1] + 8 m (26 ft) pier
Built 2002–2008
First light 2007-07-13
Telescope style Segmented Ritchey-Chrétien telescope[2]
Diameter effective =10.4 m (410 in) , maximum= 11,386.9 mm (448.30 in)[2]
Collecting area 78.54 m2 (845.4 sq ft) (74.14 m2 or 798.0 sq ft effective)[2]
Focal length 169.9 m (6,690 in)[2]
Mounting Altitude/azimuth

The Gran Telescopio Canarias (GranTeCan or GTC), also known as the Great Canary Telescope is a 10.4 m (410 in) reflecting telescope located at the Roque de los Muchachos Observatory on the island of La Palma, in the Canaries, Spain.

Construction of the telescope, sited on a volcanic peak 2,267 metres (7,438 ft) above sea level, took seven years and cost €130 million (£112 million).[3] Its installation had been hampered by weather conditions and the logistical difficulties of transporting equipment to such a remote location.[4] First light was achieved in 2007 and scientific observations began in 2009.

The GTC Project is a partnership formed by several institutions from Spain and Mexico, the University of Florida, the Universidad Nacional Autónoma de México,[5] and the Instituto de Astrofísica de Canarias (IAC). Planning for the construction of the telescope, which started in 1987, involved more than 1,000 people from 100 companies.[3]

As of 2015, it is the world's largest single-aperture optical telescope.[6] The distribution of the availability of time to use the telescope meets its financial structure: 90% Spain, 5% Mexico and 5% the University of Florida.


Dome of the GTC at sunset

First light

The GTC began its preliminary observations on 13 July 2007, using 12 segments of its primary mirror, made of Zerodur glass-ceramic by the German company Schott AG. Later the number of segments was increased to a total of 36 hexagonal segments fully controlled by an active optics control system, working together as a reflective unit.[4][7] Its Day One instrumentation was OSIRIS. Scientific observations began properly in May 2009.[8]

Inauguration ceremony

The Gran Telescopio Canarias formally opened its shutters on July 24, 2009, inaugurated by King Juan Carlos I of Spain.[9] More than 500 astronomers, government officials and journalists from Europe and the Americas attended the ceremony.


Comparison of nominal sizes of primary mirrors of the Gran Telescopio Canarias and some notable optical telescopes

The University of Florida's CanariCam is a mid-infrared imager with spectroscopic, coronagraphic, and polarimetric capabilities, which will be mounted initially at the Nasmyth focus of the telescope. In the future, when the Cassegrain focus of the telescope is commissioned, it is expected that CanariCam will move to this focus, which will provide superior performance with the instrument.

CanariCam is designed as a diffraction-limited imager. It is optimised as an imager, and although it will offer a range of other observing modes, these will not compromise the imaging capability. The fact that CanariCam offers polarimetry and coronagraphy in addition to the more standard imaging and spectroscopic modes makes it a versatile and powerful instrument.

CanariCam will work in the thermal infrared between ≈7.5 and 25 μm. At the short wavelength end the cut-off is determined by the atmosphere; specifically atmospheric seeing. At the long wavelength end the cut-off is determined by the detector; this loses sensitivity beyond ≈24 μm, although the cut-off for individual detectors varies significantly. CanariCam is a very compact design. It is expected that the total weight of the cryostat and its on-telescope electronics will be under 400 kg. Most previous mid-infrared instruments have used liquid helium as a cryogen; one of the requirements of CanariCam is that it should require no expensive and difficult to handle cryogens.

CanariCam will use a two-stage closed cycle cryocooler system to cool the cold optics and cryostat interior down to approximately 28 K (−245 °C; −409 °F), and the detector itself to around 8 K (−265 °C; −445 °F), the temperature at which the detector works most efficiently. CanariCam is expected to be installed in 2010.[10]


The IAC's OSIRIS (Optical System for Imaging and low Resolution Integrated Spectroscopy), is an "imaging and low resolution spectrograph with longslit and multiobject spectroscopic modes. It covers the wavelength range from 0.365 to 1.05 µm with a field of views (FOV) of 7 × 7 arcmin, and 8 arcmin × 5.2 arcmin, for direct imaging and low resolution spectroscopy respectively." It "provides a new generation of instrumental observation techniques such as the tunable filters, the charge-shuffling capability in the CCD detectors, etc."[11]

See also


  1. Rodríguez Espinosa, J. M.; Álvarez, P. (2002-02-05). "The GTC: STatus and Operation Plans" (PDF). RevMexAA. 16: 1–8. Retrieved 2009-07-24.
  2. 1 2 3 4 Jochum, Lotti; Castro, Javier; Devaney, Nicholas (2009-02-27). "Gran Telescopio CANARIAS : current status of its optical design and opto-mechanical support system" (PDF). Archived from the original (PDF) on August 16, 2009. Retrieved 2009-07-24.
  3. 1 2 Moreno, Carlos (2009-07-25). "Huge telescope opens in Spain's Canary Islands".
  4. 1 2 "Tests begin on Canaries telescope". BBC. 14 July 2007.
  5. GTC faq GTC digital 8 January 2009
  6. Klotz, Irene (2009-07-24). "New telescope is world's largest ... for now".
  7. Giant telescope begins scouring space July 14, 2007
  8. El Gran Telescopio CANARIAS comienza a producir sus primeros datos científicos IAC Press release June 16, 2009 (Spanish)
  9. Heckle, Harold (July 24, 2009). "Huge Telescope Opens in Spain's Canary Islands". New York Times.
  10. Hoover, Aaron (2009-07-24). "UF officials help inaugurate world's largest telescope". University of Florida News. University of Florida.
  11. "Instruments Osiris". Gran Telescopio Canarias.
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