Identification of the property

Country/State Party 

Spain

State/Province/Region 

Canary Islands

La Palma & Tenerife islands

Name 

Canarian Observatories:

• Roque de los Muchachos Observatory (ORM) - La Palma
• Teide Observatory (OT) - Tenerife

(Part of Windows to the Universe: Leading Optical Observatories)

Geographical co-ordinates and/or UTM 

ORM - La Palma:

• Latitude 28° 46′ N, longitude 17° 53′ W. Elevation 2396m above mean sea level.
• UTM Zone 28N: 0217381 3185236

OT - Tenerife:

• Latitude 28° 18′ N, longitude 16° 30′ W. Elevation 2390m above mean sea level.
• UTM Zone 28N: 0351966 3131519

Maps and plans,
showing boundaries of property and buffer zone 

See Figs CO.1 and CO.2.

Area of property and buffer zone 

ORM - La Palma

The Roque de Los Muchachos Observatory is located in an area of some 200 ha. In terms of nature and landscape conservation, the Caldera de Taburiente National Park covering 4,354 ha together with the Special Protection Area (SPA) ’Cumbres y acantilados del Norte de La Palma‘, covering 22,701 ha, are considered to be a buffer zone.

In terms of protection against light pollution, there is a core zone around the ORM void of any source of light pollution of 25,434 ha (radius 9 km) (Fig. CO.1). A Buffer Zone has been established, covering an area of 19,400 ha, including the north of the island, the dorsal ridge and large areas of the west and south of the island. Finally, an external zone of protection from light pollution was established in the Sky Law of 1988, which practically includes the whole island of La Palma and the north of Tenerife island directly visible from the site.

OT - Tenerife

The Teide Observatory is located within an area of some 100 ha inset in the Teide National Park World Heritage Site, whose size is 18,990 ha. A natural and landscape protection belt surrounds the National Park, named Parque Natural de Corona Forestal. It is considered as a buffer zone and covers an area of 46613 ha (Fig. CO.2).

Description

Description of the property 

The two observatories of the Instituto de Astrofísica de Canarias (IAC)—the Roque de los Muchachos Observatory (ORM) on the island of La Palma and the Teide Observatory (OT) on the island of Tenerife—constitute an ‘astronomy reserve’ that has been made available to the international community. The Canary Islands sky quality for astronomical observation has long been recognised worldwide. They are near to the equator yet out of the reach of tropical storms. The whole of the Northern Celestial Hemisphere and part of the Southern can be observed from them. The observatories are located 2400 m above sea level, above the temperature-inversion layer produced by the trade winds. This ensures that the installations are always above the so-called ‘sea of clouds’, where the atmosphere, stabilised by the ocean, is clean and turbulence-free.

The two observatories are currently home to telescopes and other instruments belonging to 60 scientific institutions from 19 different countries. These observation facilities, together with the scientific and technological resources of the IAC at La Laguna (Tenerife) and Centro de Astrofísica en La Palma (CALP) at Breña Baja (La Palma), make up the European Northern Observatory (ENO).

Both observatories are located in areas of the utmost value from an environmental point of view, with exceptional natural scenery. The ORM (Fig. CO.3) is situated at the edge of the Caldera de Taburiente National Park (Fig. CO.1), a spectacular erosion caldera covered by vegetation. It is located at 2,396 m above sea level in the municipality of Garafía. It is home to one of the most extensive fleets of telescopes to be found anywhere in the world. A number of archaeoastronomical sites, such as Lomo de las Lajitas, are also located within its area.

The ORM is located within the core zone of the La Palma Bio- sphere Reserve declared in 2002 by UNESCO. This is the first case of Biosphere Reserve zoning that includes areas of exceptional sky quality in its core zone. It is also included within the Special Protection Area (SPA) (Natura 2000) called ’Barlo- vento, Garafía, El Paso y Tijarafe‘.

The Teide Observatory (OT) (Fig. CO.4) is located on the border of the Teide National Park World Heritage Site (Fig. CO.2). As the inscription text states (statement of Outstanding Universal Value under criterion (vii)): ’Mount Teide is a striking volcanic landscape dominated by the jagged Las Cañadas escarpment and a central volcano that makes Tenerife the third tallest volcanic structure in the world. Within this landscape is a superlative suite of landforms that reveal different phases of construction and remodelling of the volcanic complex and highlight its unique geodiversity. The visual impact is emphasized by atmospheric conditions that create constantly changing textures and tones in the landscape and a ‘sea of clouds’ that forms a visually impressive backdrop to the mountain‘. At night, the landscape is dominated by the stunning clearness of the starry sky and the profile of Mount Teide itself.

Administratively it is not included within the National Park, for reasons of territorial manage- ment, but yet it shares all the natural and scenic values ├ö├çï├ö├çïof its surroundings. That is why the OT area is within the SPA ’Parque Nacional del Teide‘. It is situated 2.390 metres above sea level in Izaña, an area of Tenerife that lies across three municipal districts: La Orotava, Fasnia and Güímar.

Its geographical location (between the eastern and western solar observatories), together with the clarity and excellent quality of the sky, make the Teide Observatory ideally suited for studying the sun. For this reason it is home to Europe’s finest solar telescopes.

The main telescopes are:

• ORM: 10.4m Gran Telescopio CANARIAS (GTC), 4.2m William Herschel Telescope (WHT), 3.5m Telescopio Nazionale GALILEO, 2.56m Nordic Optical Telescope (NOT), 2.5m Isaac Newton Telescope (INT), 2m Liverpool Telescope, 1.2m MERCATOR, 0.45m Dutch Open Telescope (DOT), 1m Solar Telescope (SST), MAGIC I and II (which detect very-high-energy gamma rays), SuperWASP-North (robotic observatory).
• OT: 1.55m CARLOS SáüNCHEZ, 1m OGS, 0.8m IAC-80, 0.5m MONS, 0.4m OTA, 1.5GREGOR (Solar), 0.9m THEMIS (Solar), 0.7m VTT (Solar), 0.3m Bradford Robotic Telescope, 1.2m Robotic telescopes STELLA.

History and development 

Both Canarian observatory sites are areas where the past astronomical culture of the ancient inhabitants combined with the birth of modern astronomy in the 18th century.

High mountains were typically regarded as sacred by Mediterranean cultures, and this was also common among protohistoric societies of the Maghreb area. The idea of the Axis Mundi can also be applied to Mount Teide. This great volcano supported the belief that the sky was maintained by a pillar supporting the two physical realities, sky and earth, and by extension the two worlds (upper and lower), where good spirits and evil beings were located.

In the Guanche cosmogony (the ’Guanches‘ were the ancient inhabitants of Tenerife island) Mount Teide was the prime sacred mountain and provided a symbolic reference to the aboriginal inhabitants of the other Canary Islands, such as the awara people living on the neighbouring island of La Palma. It also was a reference for majos people living on the remote island of Fuerteventura, as shown by the exceptional foot-shaped engravings found in their sacred mountain Tindaya. The archaeoastronomer Juan Belmonte has shown that the orientation of these was determined both astronomically (to the winter solstice and other celestial phenomena) and topographically (orientation to Mount Teide).

The Roque de los Muchachos was also of crucial importance within the ancient awara culture on La Palma, as is clear from the archaeological evidence at a number of sites such as ‘Lomo de Las Lajitas’, located within the observatory area. This site consists of more than a dozen sacrificial altars and a series of rock carvings with evident astronomical significance.

The Teide mountain is world-renowned for its contribution to science in modern times, especially in the field of geology and the study of the atmosphere. The Teide National Park was inscribed on the World Heritage List in 2007 under natural criteria (vii) and (viii). Its connection with science is evident from the inscription text: ’The area is a major centre for international research with a long history of influence on geology and geomorphology especially through the work of von Humboldt, von Buch and Lyell, which has made Mount Teide a significant site in the history of volcanology‘.

One thing not mentioned in the case for inscription to the World Heritage List was the fact that some members of scientific expeditions to the Canaries, such as Humboldt in 1799, made pioneering atmospheric observations. Mount Teide was a priority objective of the about thirty scientific expeditions to the Canary Islands that took place between 1770 and 1830.

In his book Opticks (1730), Isaac Newton suggested that telescopes should be installed where the atmosphere was calmer and more stable, that being what happens upon the highest mountain peaks, above the cloud layer. Following this suggestion, the British astronomer Piazzi Smyth (1856) first demonstrated that high-altitude sites offered clear advantages for astronomical observation. He reached this conclusion after making observations at several altitudes on Tenerife, from sea level up to the mountains of Guajara (2,717 m) and Altavista (3,250 m) on the Teide volcano. These experiences can be considered the starting point of the development of the large advanced observatories of the present day—the ’Windows to the Universe‘—that have revolutionized our understanding of the cosmos.

Piazzi Smyth presented these findings to the British Government and to the Royal Society, before publishing them in 1857 in its book Teneriffe: An Astronomer Experiment. These works show the clear advantages of these mountain areas, including the detection and measurement of faint stars and the quality of the diffraction rings in the telescope focus (low seeing). In June 1895, Knut Angström and his collaborators settled upon the former site of Piazzi Smyth, at Altavista, 3,252m above MSL. At that time the first ’reliable‘ measurements were made of solar radiation at different altitudes (Altavista, Las Cañadas, Puerto de la Cruz, Santa , and Güímar) (Angström, 1901).

In 1910 the French astronomer Jean Mascart travelled to the Canary Islands specifically to observe the passage of Halley’s Comet (Fig. CO.5). On that occasion Mascart proposed the creation of an international observatory on the Teide, on Guajara Mountain, very close to the present site. However, the idea was shelved owing to World War I.

Five decades later, in 1959, the total eclipse of the sun, visible from the Canaries, once again attracted the attention of numerous investigators and astronomers and the idea of creating an astronomical observatory on these islands resurfaced. In 1960, Prof. Francisco Sánchez and Prof. Torroja y Romaña laid the groundwork for today’s Canarian Observatories, exploring both the areas that subsequently became the ORM and OT.

The Observatorio del Teide was founded in 1959, and the first telescope arrived in the area in 1964, thanks to an agreement with the University of Bordeaux. In 1975 the Instituto de Astrofísica de Canarias was founded by the Instituto de Astrofísica, as part of the University of La Laguna. In 1979, Spain signed the ’Agreement and Protocol of Cooperation in Astrophysics‘ with Denmark, Sweden, and the United Kingdom, which brought modern telescopes to the observatories. Presently, both observatories offer facilities for night-time study as well as solar studies, using telescopes and other astronomical instruments from 19 countries.

The ensemble of observatories on the Canary Islands has played an important role in astronomy, being the place where, for example, the optical counterpart of a Gamma Ray Burst was first observed, the first unequivocal evidence for a stellar-sized black hole in the Galaxy was obtained (something that had been sought for decades), and the first brown dwarf was discovered.

The GTC (Gran Telescopio Canarias), at present the largest optical and infrared telescope in the world, will ’see‘ the farthest and faintest objects in our Universe, and will help provide answers to many questions about how the known universe was created.

Justification for inscription

Comparative analysis 

See Windows to the Universe: Leading Optical Observatories (general description)

Integrity and/or authenticity 

See Windows to the Universe: Leading Optical Observatories (general description)

Criteria under which inscription might be proposed 

See Windows to the Universe: Leading Optical Observatories (general description)

Suggested statement of OUV 

See Windows to the Universe: Leading Optical Observatories (general description)

State of conservation and factors affecting the property

Present state of conservation 

The sky protection law has been in place for 24 years, and has provided good protection for the night sky, especially on the island of La Palma. The Instituto de Astrofísica de Canarias (IAC), long aware of the importance of promoting initiatives to protect the ORM and OT, created a Sky Quality Group in the late 1980s and a technical office for sky protection (OTPC) in 1992 to provide advice on the application of the Sky Law.

The level of protection has been increasing in recent years, overcoming the initial reluctance of the local population. Better enforcement is expected in the future. The present level of light pollution does not compromise research, maintaining the high level of excellence of the sky quality parameters.

Factors affecting the property 

Developmental pressures

In neither of the two cases is any territorial or environmental pressure recorded, since they are located within protected areas. The only exception in these areas is for astronomical use or uses related to education and low-impact ecotourism.

Environmental pressures

There are no significant environmental pressures since both areas are well preserved.

The main pressure may come from light pollution that affects sky quality. The big problem of light pollution is that it can have an impact at tens or even hundreds of kilometres from the polluting source, both directly and by contributing to sky glow. This pressure is especially important on Mount Teide, where in the last two decades there has been a considerable increase in light pollution in Valle de La Orotava, Santa Cruz metropolitan area, and in the tourist resorts of the south of the island.

This factor has a lower impact in the case of La Palma, especially after much work being done to improve and replace the older outdoor lighting with less polluting systems, following the provisions of the Sky Law. In any case this is a process of continuous innovation and improvement to achieve the minimum pollution levels. It should be emphasized that sky protection is strictly linked to higher efficiency and more sustainable use of energy. La Palma figures indicate that the introduction of non-polluting luminaires and lamp types will lead to an energy saving of around 40% from the current scenario. This will result in a significant reduction in CO₂ emissions and an effective contribution in the fight against climate change.

Visitor/tourism pressures

The ORM and the edge of the Caldera de Taburiente National Park are both prime tourist attractions on the island. However, visits to the observatory area are regulated. In particular, nocturnal visits are very limited due to restrictions related to the operability of the telescopes.

In general, there are no significant tourist pressures in the observatory and its surroundings, since visitor flow is well regulated by the IAC and the National Park administration. There is also a set of requirements that are updated through the Public Use Plan of La Palma Biosphere Reserve.

Visitor pressure on Mount Teide is very significant, as it is among the most visited National Parks in Europe and worldwide. The park’s Use and Management Master Plan and the Park Management Trust address its regulation as a priority. However, visits for educational and astro-tourist purposes in the observatory area are also well regulated by the Observatory Management Board. Moreover, astro-tourist activities at night in its surroundings comply with minimal pressure criteria, as they are concentrated in the park’s hosting facilities that minimize their impact.

Number of inhabitants

There is no permanent population in either of the two observatories. The presence of people is limited to the observatories’ maintenance personnel, scientists and operators.

Protection and management

Ownership 

Both observatory areas are municipality-owned and administrated by the Instituto de Astrofísica de Canarias (IAC).

The IAC is constituted administratively as a Public Consortium, with involvement from the Spanish Government, the Government of the Canary Islands, the University of La Laguna and Spain’s Science Research Council (CSIC).

Protective designation 

The whole area where each observatory is located enjoys a high level of protection. Each of the observatories is located within a European Special Area for Conservation (SPA - Natura 2000 Network), and lies at the edge of a National Park.

The astronomical quality of the Canary Islands’ observatories is guaranteed under a specific national ‘Sky Law’ (‘Ley del Cielo’—Law 31/1988) approved in 1988.

Relying upon this regulatory development, a high-sensibility ‘core area’ has been established around the ORM, extending 9 km in each direction. The rest of the island of La Palma (25 km around the Observatory) is considered a high-protection buffer zone, while the external zone is the area visible from La Palma, 100-160 km around the Observatory, which includes the island of Tenerife. The protection also covers radio and atmospheric pollution (prohibiting emission sources above 1500m elevation), and air traffic.

One of the IAC’s greatest successes in its work to protect the observatories was the designation of the airspace above them as an "Ecological Protection Zone‘ on 17th May 1998.

Means of implementing protective measures 

The exceptional quality of the sky for observation over the Canaries is protected by Law 31/1988; which is known as the ’Sky Law‘.

Sky Quality Group

A team of scientists within the IAC (Sky Quality Group) is responsible for the ‘Characterisation of the Canarian Observatories’. The SQG ensures that the atmospheric parameters determining the astronomical quality of observations are continually monitored and updated. The objectives of this group were the determination and characterisation of optical-infrared quality, as well as meteorological conditions, at the observatories. These studies were completed with geophysical tests.

The Observatories in Chile, Hawaii and the Canaries are the only ones to have conducted intensive astronomical prospecting campaigns; Chile and the Canaries are unique in that they have developed extensive and reliable databases.

Sky Quality Protection Technical Office

The Sky Quality Protection Technical Office (OTPC) was set up by the IAC in January 1992 to provide advice on the application of the Sky Law (Law 31/1988), which protects the astronomical quality of observatories in the Canaries from:

• light pollution
• radioelectrical pollution
• atmospheric pollution
• aviation routes

The OTPC provides advice on the application of regulations contained in the Law and produces technical reports for lighting projects and radioelectric stations, as well as issuing lighting certificates.

Visitor facilities and infrastructure 

The ORM is a focal point for star tourism development and a unique attraction on the island of La Palma. The Observatory allows organized groups from schools, universities, professionals or interested tourists to visit its telescopes and facilities. The ORM receives about 5000 visitors annually. However, in order to satisfy the demands of the increasing number of visitors, the Roque de Los Muchachos Cultural Park will be completed in a few years not far from the observatory itself, and it will allow visits to be channelled to the Roque. Apart from its astronomical content this Cultural Park will emphasize the natural and cultural heritage of the area.

Outreach and educational activities carried out by the IAC for many years are the reason behind the present boom in star-tourism on the island. In order to consolidate an advanced, sustainable, and scientifically supported tourist destination, the best areas of the island enjoying excellent sky conditions have been certified as a Starlight Tourist Destination. Within the framework of the Starlight strategy, the island Government of La Palma has developed a network of star-viewpoints and thematic trails, which give great support to this new dimension of tourism. An added benefit is that part of the flow of this tourist activity is diverted to other areas, ensuring a maximum level of protection around the ORM. Guides are required to possess a Starlight accreditation in order to guarantee an appropriate scientific and interpretive level, and best-practice guidelines have been developed so as not to threaten the resource.

Studies of rural tourism on La Palma give a good idea of the level of demand for star-tourism. In the 2008 survey on "Main leisure and recreational activities", star observation is in fourth place with a surprising 80.38% of positive responses. This is a very significant number, that puts star observation higher than other activities related to cultural and nature tourism. In other words, tourists identify the sky of La Palma as a prime tourist attraction.

Teide National Park is the most visited protected natural area in Spain; it receives around 3.5 million visitors a year, i.e. an average of 9,600 people a day. However, the figure for nocturnal visits related to the observation of stars is significantly lower, averaging 60,000 visitors. Most astro-tourist night activities take place outside the area of the Observatory.

Visits to the Teide Observatory are regulated, and they are mainly educational, but open days take place and are quite often crowded. The OT relies on advanced educational and interpretive resources such as the Cosmos trail and the Dome for the popularisation of astronomy. Innovative measures such as educational projects with Robotic Telescopes (PETER) or the Virtual Telescope (IAC-80 located in the OT) have been added.

Staffing levels and expertise 

The Instituto de Astrofisica de Canarias (IAC) is an internationalized Spanish research centre. It has two headquarters and two observatories. Altogether about 400 people work here, this number comprising researchers, technology developers, engineers, project managers, and administrative staff.

Monitoring

Indicators for measuring state of conservation 

Environmental and nature conservation

The Canary Islands’ Biodiversity Data Bank is constantly monitoring parameters related to biodiversity conservation and potential impacts on the integrity of the areas containing both observatory sites, since both are Special Areas of Conservation (SAC) and Special Protection Areas (SPA). These indicators include the numbers of endangered species and other trends important for conservation purposes, such as the introduction of invasive alien species. The first data on nocturnal wildlife species are being obtained. Their best protection depends upon the absence of light pollution, since this would decrease their distribution and abundance.

Archaeoastronomical heritage

Indicators relating to archaeoastronomical heritage are deduced from the archaeological maps of both islands, which set out an assessment of existing heritage.

Sky quality

Sky quality indicators are monitored continuously, in particular astronomical quality parameters related to darkness, atmospheric conditions, seeing, and transparency.

Useful Time (of clear sky) and meteorological parameters. It is essential to know the local meteorology and climate in the area studied—the presence of cirrus clouds, dust in suspension, air temperature, relative humidity, barometric pressure, rain gauge levels, direction and velocity of the wind, etc.—and its possible correlation with image quality. To do this, there are automatic meteorological stations equipped with standard meteorological sensors. The infrequency of cirrus clouds, moderate temperatures and the semi-presence of trade winds allow for a high percentage of observation hours and contribute to the excellent quality of the astronomical images.

A key factor is the degree of disturbance caused by light pollution on natural darkness conditions at night at the site. Both the SQG and the OTPC continuously monitor light pollution trends in order to propose at any moment the corrective measures to deal with any deviation.

Atmospheric Extinction (transparency). The term ‘extinction’ means the loss of light in the atmosphere from a directly transmitted beam. Two different mechanisms contribute to extinction: absorption and scattering.

Seeing (for sharp images). Astronomical ’seeing‘ refers to the blurring and twinkling of astronomical objects such as stars caused by turbulence in the Earth’s atmosphere. In order to get smaller ’seeing‘ values (only obtained in the best locations) sophisticated techniques and instrumentation which have been developed in the last decade are needed. There are two prototype instruments in existence: one of them was built by the European Southern Observatory (ESO) and the other was created by the IAC in collaboration with the University of Nice (France). They have been calibrated to each other and are producing the most convincing and modern data of the Canarian Observatories as well as those of the ESO in Chile (La Silla and Paranal).

The measurement and statistical analysis of parameters related to atmospheric turbulence are crucial for the selection and characterization of the best astronomical observing sites. These parameters require continuous monitoring and updating. The largest statistical study of atmospheric turbulence profiles in the world was achieved for the ORM.

The SQG web site has been set up to provide detailed information and statistics about meteorological and seeing data at different locations at the Canarian Observatories, as provided by different instruments and campaigns. Data files and charts are also available, as well as other related information. The Site Characterization Study is funded by the IAC and co-funded by European Commission FP6 programme.

Documentation

Photos and other AV materials 

Time-lapse - Teide

Texts relating to protective designation 

Law for the Protection of the Astronomical Quality of the IAC Observatories - Law 31/1988. (pdf)

Regulations for the law - R.D. 243/1992. (pdf)

Lighting installation criteria. (pdf)

Protected airspace and occupation procedure. 2001. (pdf)

Other overflight restrictions. 2005. (pdf)

Decision: 31 COM 8B.17. Decisions Adopted at the 31st session of the World Heritage Committee (Christchurch, 2007). Inscription of the Teide National Park, Spain, on the World Heritage List

Plan Rector de Uso y Gestión del Parque Nacional del Teide. (Teide Management Plan)

Special Areas of Conservation (Natura 2000)

La Palma Biosphere Reserve - Zonification

Bibliography 

UNESCO (2007), WHC-07/31.COM/8B, Convention Concerning the Protection of the World Cultural and Natural Heritage, World Heritage Committee, Thirty first Session, Christchurch, New Zealand, 23 June - 2 July 2007

IUCN (2007), World Heritage Nomination - IUCN technical evaluation report. Teide National Park (Spain) - id no. 1258.

Angström, K., 1901, Intensité de la radiation solaire ├á differentes altitudes. Récherches faites ├á Teneriffe 1895 et 1896, Nova Acta Rigiae Societatis Scientiarum Upsaliensis, Serie 3, 20, 1.

Belmonte, J.A. (coord.) (2000): Arqueoastronomía Hispánica. Prácticas astronómicas en la Prehistoria de la Península Ibérica y los archipiélagos balear y canario. Equipo Sirius, 2Ôö¼┬¼ ed. Madrid.

Belmonte, J.A. y Sanz De Lara, M. (2001): El cielo de los Magos. La Marea. Santa Cruz de Tenerife.

del Puerto, Carmen (Responsable de contenido). Historia Reciente del IAC (1961-1998), Instituto de Astrofísica de Canarias.

Durbán Villalonga, M. y Reverón Gómez, J. (coord.) (2006), Proposal to Inscribe Teide National Park on the World Heritage List, Ministerio de Medio Ambiente - Gobierno de Canarias, Santa Cruz de Tenerife.

Fernández Hernández, C. y otros (2008): Estudio del Mercado del turismo rural en la isla de La Palma: análisis de la demanda, Asociación de Turismo Rural Isla Bonita, Santa Cruz de Tenerife.

Fernández Hernández, C. (2009): Turismo de estrellas: oportunidades para la isla de La Palma, Seminario Senderismo bajo las estrellas, ADER-La Palma, La Palma.

Mahoney, T., Muñoz-Tulón, C. & Varela, A.M. 1998. GTC site-testing campaign: meteorology. New Astronomy Reviews 42: 417-424.

Marín, C., Jafar, J., 2008. Starlight: A Common Heritage. UNESCO, IAU, Instituto de Astrofísica de Canarias.

Mascart, J., 1910, ’Photographies de la Comète de Halley‘, Comptes rendues de l’Académie des Sciences, 6 Juin et 25 Juillet.

Mascart, J., 1912, Impressions et Observations dans un voyage à Teneriffe, Ernest Flammarion, Paris.

Ministerio de Medio Ambiente - Gobierno de Canarias, 2006. Proposal to inscribe Teide National Park on the World Heritege List.

Muñoz-Tunón, C. A., Varela Pérez, M. y del Puerto, Carmen, Historia del IAC — Primeras expediciones Astronómicas (1856 -1959), Instituto de Astrofísica de Canarias.

Müller, G, Kron, E., 1913, Die Extinktion des Lichtes in der Erdatmosphare und die Energieverteilung in Sonnespektrum auf der Insel Teneriffa, Publik. Astroph. Obser. Postdam, 64, 22, 1-92.

Newton, I., 1730, Opticks.

Secretaría General de Turismo (2004): El turismo de naturaleza en España y su plan de impulso, Secretaria General de Turismo, Madrid.

World Heritage International Expert Meeting on Science and Technology, London, 2008. Background Document. UNESCO World Heritage Centre.