Calar Alto Observatory

Enclosure of the 2.2-meter telescope at Calar Alto Observatory
Alternative names	Spanish Astronomical Centre in Andalusia
Organization	Institute of Astrophysics of Andalusia (IAA-CSIC) Council of Andalusia
Observatory code	493
Location	Almería, Spain
Coordinates	37°13′25″N 2°32′46″W / 37.22361°N 2.54611°W / 37.22361; -2.54611
Altitude	2,168 m (7,113 ft)
Website	www.caha.es
Telescopes
Unnamed 3.5 m reflector 37°13′15″N 2°32′49″W / 37.220791°N 2.5468465°W / 37.220791; -2.5468465 Unnamed 2.2 m reflector 37°13′23″N 2°32′46″W / 37.2231427°N 2.5461943°W / 37.2231427; -2.5461943 Unnamed 1.5 m reflector 37°13′30″N 2°32′55″W / 37.2249718°N 2.5484985°W / 37.2249718; -2.5484985 Unnamed 1.23 m reflector 37°13′23″N 2°32′52″W / 37.223074°N 2.5476775°W / 37.223074; -2.5476775 Unnamed 0.8 m Schmidt reflector 37°13′26″N 2°32′54″W / 37.223927°N 2.5483678°W / 37.223927; -2.5483678
Location of Calar Alto Observatory
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The Calar Alto Observatory (Centro Astronómico Hispano en Andalucía or "Spanish Astronomical Centre in Andalusia") is an astronomical observatory located in Almería province in Spain on Calar Alto, a 2,168-meter-high (7,113 ft) mountain in the Sierra de Los Filabres subrange of the Sierra Nevada.^[2]

Until 2018, Calar Alto was owned and operated jointly by the German Max Planck Institute for Astronomy in Heidelberg, and the Spanish Institute of Astrophysics of Andalusia (IAA-CSIC) in Granada. It was named the "German–Spanish Astronomical Centre" (in Spanish, Centro Astronómico Hispano-Alemán (CAHA); in German, Deutsch-Spanisches Astronomisches Zentrum). In 2019, the Council of Andalusia takes over the German partner, sharing the observatory with the Spanish National Research Council through its head institute, IAA-CSIC.

Calar Alto telescopes are used for a broad range of observations, from objects in the Solar System^[2] to cosmology (the Alhambra and CALIFA surveys), including the search for exoplanets (the CARMENES survey).

The 3.5-meter telescope is the second-largest telescope in mainland Europe after the 4-meter Eastern Anatolian Observatory telescope^[3], though there are three larger telescopes on the Spanish island of La Palma at the Roque de los Muchachos Observatory. The minor planet 189202 Calar Alto, discovered by Felix Hormuth at Starkenburg Observatory in 2003, was named in honor of the observatory site.^[2]

The site was proposed in 1970, and was officially opened in July 1975 with the commissioning of its 1.23-meter (48 in) telescope. The site developed thanks to German and Spanish cooperation in astronomy. Eventually, four more telescopes were commissioned. The Schmidt telescope was moved to Calar Alto in 1976 from the Hamburg Observatory at Bergedorf, where it had been completed in 1954. The observatory hosted the finish of Stage 11 of the 2017 Vuelta a España cycling race (the stage was won by Miguel Ángel López), having previously hosted stage finishes in 2004 (won by eventual race champion Roberto Heras) and 2006 (won by Igor Antón). Calar Alto was climbed on Stage 9 of the Vuelta (AUG 2021).

There are 4 main telescopes on site: a 3.5-meter (138-inch), 2.2 m (87 in), and a 1.23 m (48 in) telescope, and an 80 cm (31 in) Schmidt reflector. The 3.5-meter is the largest telescope on European soil with an equatorial mount. There is also a 1.52 m (60 in) telescope that is owned and operated by the Spanish National Observatory and a robotic telescope operated by the Spanish Astrobiology Center (CAB).

The CALIFA survey (Calar Alto Legacy Integral Field Area survey) is an astronomical project to map 600 galaxies with imaging spectroscopy (integral field spectroscopy (IFS)).^[4]

The CARMENES survey (Calar Alto high-Resolution search for M-dwarfs with Exoearths with Near-infrared and optical Échelle Spectrographs) is a project to examine approximately 300 M-dwarf stars for signs of exoplanets with the CARMENES instrument on Calar Alto's 3.5m telescope. Operating since 2016, it aims to find Earth-sized exoplanets around 2 M_E (Earth masses) using Doppler spectroscopy (also called the radial velocity method).^[5][6]

Close to a hundred minor planets have been discovered at Calar Alto by astronomers Luboš Kohoutek, Kurt Birkle, Ulrich Hopp, Johann Baur, Krisztián Sárneczky, Gyula Szabó, Felix Hormuth and Hermann Boehnhardt. In addition, the Minor Planet Center, directly credits "Calar Alto" with the discovery of the following minor planets:^[1]

• Elsässer, H. (1975). "Kurze Berichte über die wissenschaftlichen Vorträge". Mitteilungen der Astronomischen Gesellschaft Hamburg. 36: 53. Bibcode:1975MitAG..36...53E.
• Lemke, D.; Frey, A.; Hefele, H.; Schulte in den Bauemen, J. (1978). "Observational conditions for infrared photometry on Calar Alto". Mitteilungen der Astronomischen Gesellschaft Hamburg. 43: 98–103. Bibcode:1978MitAG..43...98L.
• Elsässer, H. (1981). "Calar Alto - bisherige Erfahrungen, künftige Entwicklung". Mitteilungen der Astronomischen Gesellschaft Hamburg. 54: 15. Bibcode:1981MitAG..54...15E.
• Fried, J. (1987). "Das 3.5-m Teleskop auf dem Calar Alto". Mitteilungen der Astronomischen Gesellschaft Hamburg. 68: 27. Bibcode:1987MitAG..68...27F.
• Birkle, K.; Hopp, U. (1987). "The Calar Alto 3.5 m Telescope. Operation and Test Results". Mitteilungen der Astronomischen Gesellschaft Hamburg. 68: 12. Bibcode:1987MitAG..68...12B.
• Hopp, U.; Graser, U. (1990). "Optical quality of the Calar Alto 3.5 m telescope". Astronomy and Astrophysics. 235 (1–2): 543–548. Bibcode:1990A&A...235..543H.
• Bizenberger, Peter; McCaughrean, Mark J.; Birk, Christoph; Thompson, Dave; Storz, Clemens (1998). "Omega Prime: The wide-field near-infrared camera for the 3.5-m telescope of the Calar Alto Observatory". In Fowler, Albert M (ed.). Omega Prime: the wide-field near-infrared camerea for the 3.5-m telescope of the Calar Alto observatory. Infrared Astronomical Instrumentation. Vol. 3354. p. 825. Bibcode:1998SPIE.3354..825B. doi:10.1117/12.317219. S2CID 67836271.
• Lenzen, Rainer; Bizenberger, Peter; Salm, Norbert; Storz, Clemens (1998). "Omega Cass: a new multimode NIR-imager/spectrometer for the Calar Alto Observatory". In Bely, Pierre Y; Breckinridge, James B (eds.). Infrared Astronomical Instrumentation. Space Telescopes and Instruments V. Vol. 3356. p. 493. Bibcode:1998SPIE.3354..493L. doi:10.1117/12.317275. S2CID 122853596.
• Bailer-Jones, Coryn A. L.; Bizenberger, Peter; Storz, Clemens (2000). Iye, Masanori; Moorwood, Alan F. M (eds.). "Achieving a wide field near infrared camera for the Calar Alto 3.5m telescope". Proc. SPIE. Optical and IR Telescope Instrumentation and Detectors. 4008: 1305. arXiv:astro-ph/0003072. Bibcode:2000SPIE.4008.1305B. doi:10.1117/12.395447. S2CID 14213535.
• Hippler, Stefan; Kapser, Markus E.; Feldt, Markus; Weiss, Robert (2000). Wizinowich, Peter L. (ed.). "ALFA: three years of experience in adaptive optics with a laser guide star". Proc. SPIE. Adaptive Optical Systems Technology. 4007: 41. Bibcode:2000SPIE.4007...41H. doi:10.1117/12.390397. S2CID 55009526.
• Wolf, C.; Meisenheimer, K.; Röser, H. -J.; Beckwith, S. V. W.; Chaffee, F. H.; Fried, J.; Hippelein, H.; Huang, J. -S.; Kümmel, M.; Von Kuhlmann, B.; Maier, C.; Phleps, S.; Rix, H. -W.; Thommes, E.; Thompson, D. (2001). "Multi-color classification in the calar alto deep imaging survey". Astronomy and Astrophysics. 365 (3): 681. arXiv:astro-ph/0010604. Bibcode:2001A&A...365..681W. doi:10.1051/0004-6361:20000064. S2CID 16378273.
• Graser, U.; Hopp, U. (1991). "Pointing models for the Calar Alto 2.2 M and 3.5 M telescopes". Astronomy and Astrophysics. 251 (2): 737–742. Bibcode:1991A&A...251..737G.
• Baumeister, Harald; Bizenberger, Peter; Bayler-Jones, Coryn A. L.; Kovacz, Zoltan; Röser, Hermann-Josef (2003). Iye, Masanori; Moorwood, Alan F. M (eds.). "Cryogenic engineering for OMEGA2000: design and performance". Proc. SPIE. Instrument Design and Performance for Optical/Infrared Ground-based Telescopes. 4841: 343. Bibcode:2003SPIE.4841..343B. doi:10.1117/12.461003. S2CID 119359237.
• Ziad, A.; Gredel, R.; Aceituno, J.; Borgnino, J.; Hoyo, F.; Irbah, A.; Martin, F.; Thiele, U.; Pedraz, S. (2005). "A site-testing campaign at the Calar Alto Observatory with GSM and DIMM instruments" (PDF). Monthly Notices of the Royal Astronomical Society. 362 (2): 455. Bibcode:2005MNRAS.362..455Z. doi:10.1111/j.1365-2966.2005.09299.x.
• Sanchez, S. F.; Aceituno, J.; Thiele, U.; Perez-Ramirez, D.; Alves, J. (2007). "The night sky at the Calar Alto Observatory". Publ. Astron. Soc. Pac. 119 (860): 1186. arXiv:0709.0813. Bibcode:2007PASP..119.1186S. doi:10.1086/522378. JSTOR 10.1086/522378. S2CID 14756942.
• Baumeister, H.; Alter, M.; Cárdenas Vázquez, M. C. N.; Fernandez, M.; Fried, J.; Helmling, J.; Huber, A.; Ibáñez Mengual, J. M.; Rodríguez Gómez, J. F.; Laun, W.; Lenzen, R.; Mall, U.; Naranjo, V.; Ramos, J. R.; Rohloff, R. R.; García Segura, A.; Storz, C.; Ubierna, M.; Wagner, K. (2008). "PANIC: the new panoramic NIR camera for Calar Alto". In McLean, Ian S; Casali, Mark M (eds.). Ground-based and Airborne Instrumentation for Astronomy II. Vol. 7014. p. 70142R. arXiv:0807.4064. doi:10.1117/12.788796. S2CID 119286504.
• Sanchez, S. F.; Thiele, U.; Aceituno, J.; Cristobal, D.; Perea, J.; Alves, J. (2008). "The night sky at the Calar Alto Observatory II: The sky at the near-infrared". Publ. Astron. Soc. Pac. 120 (873): 1244. arXiv:0809.4988. Bibcode:2008PASP..120.1244S. doi:10.1086/593981. JSTOR 10.1086/593981. S2CID 14756942.
• Quirrenbach; Amado; Mandel; Caballero; Ribas; Reiners; Mundt; Abril; Afonso (2009). "CARMENES: Calar Alto high-Resolution search for M dwarfs with Exo-earths with a Near-infrared Echelle Spectrograph". arXiv:0912.0561 [astro-ph.SR].
• Husemann, B.; jahnke, K.; Sanchez, S. F.; Berrado-Navscues, D. (2012). "CALIFA, the Calar Alto Legacy Integral Field Area survey". Astronomy & Astrophysics. 549: A87. arXiv:1210.8150. doi:10.1051/0004-6361/201220582. S2CID 46141773.

• List of largest optical reflecting telescopes
• List of largest optical telescopes in the 20th century
• Cerro Tololo Inter-American Observatory
• La Silla Observatory
• List of minor planet discoverers
• Llano de Chajnantor Observatory
• Paranal Observatory
• Very Large Telescope

• "Calar Alto Observatory homepage". Centro Astronómico Hispano Alemán. Retrieved December 12, 2005.

• Calar Alto: Darkness In The Infrared ScienceDaily (Jan. 30, 2009)
• bird's eye view