We will not be running excursions from August 10th to 16th due to the holidays. Eclipse Guide
Teide Observatory, a beacon of science in the heart of the universe
Located at an altitude of almost 2,400 meters in Teide National Park, the Teide Observatory is one of the world's most important centers for astronomical research. Far from being just a destination for stargazing, this observatory is a cornerstone of scientific discovery, from the study of the Sun to the exploration of distant galaxies.
Introduction
Under the crystal-clear sky of the Teide Observatory, in Tenerife, the history of astrophysics in the Canary Islands is being written.
Since its founding in 1964, when a telescope from the University of Bordeaux began studying zodiacal light—the diffuse glow created by interplanetary dust—this site at an altitude of 2,390 meters has become a beacon of global science. The clarity of its skies and its strategic location have made it ideal for exploring everything from the Sun to the far reaches of the cosmos.
The Teide Observatory is the birthplace of scientific milestones. In 1979, it gave rise to helioseismology, the science that studies the Sun's vibrations to unravel its inner secrets. State-of-the-art solar telescopes, such as GREGOR, one of the most advanced in Europe, analyze our star with unprecedented detail.
But Teide's work doesn't stop at daytime: its nighttime telescopes have monitored historic comets, such as Shoemaker-Levy 9, mapped the center of our galaxy, and discovered the first brown dwarf, named Teide 1, an object between a star and a planet. Furthermore, pioneering experiments have detected anisotropies in the cosmic microwave background, echoes of the Big Bang that reveal the origins of the universe.
Today, the observatory combines tradition and modernity. Its robotic telescopes, such as those of the Two-meter Twin Telescope (TTT) project, explore exoplanets, black holes, and potentially hazardous asteroids, while preparing to detect primordial gravitational waves, a window into the early universe.
The Observatory Residence, operational since 1990, supports the scientific staff, and the Canary Islands Institute of Astrophysics (IAC) brings the stars closer to the community with school visits to a dome converted into a dissemination center.
The Teide Observatory not only illuminates the cosmos, but also inspires generations to look to the sky. It is a source of pride for the Canary Islands and a reminder that, from this island, the universe is a little closer.
A prime center for solar astronomy
The Teide Observatory, managed by the Canary Islands Institute of Astrophysics (IAC), is recognized as the world's largest solar observatory.
Their telescopes, such as GREGOR and the Vacuum Tower Telescope (VTT), are designed to study the Sun in unprecedented detail. Scientists here investigate phenomena such as:
- Sunspots: Regions of intense magnetic activity that affect space weather.
- Solar flares: Explosions that release energy equivalent to millions of nuclear bombs.
- Solar prominences: Plasma arcs that reveal the secrets of the solar atmosphere.
Each day, the observatory produces at least one scientific publication, contributing to our understanding of how the Sun influences Earth and other planets. For example, its data helps predict solar storms that can affect satellites, power grids, and communications.
Why is Mount Teide ideal for astronomy?
The Teide Observatory is not just anywhere; its location in the Teide National Park is a key factor in its success.
The environmental conditions create a perfect natural laboratory for astronomy; the main reasons are as follows:
- Clear skies: With only 400 mm of annual rainfall and a clean atmosphere thanks to the trade winds, Teide offers more than 78% of the time usable for observations, meaning that most nights and days are clear.
- Low light pollution: Certified as a Starlight Destination, the altitude and distance from urban centers guarantee dark skies.
- Atmosphere: The island enjoys a stable atmosphere, especially at high altitudes, with low atmospheric turbulence, which reduces distortions, crucial for high-precision telescopes and experiments
- Geographical location: Tenerife is located at a latitude that allows observation of both the northern hemisphere sky and part of the southern hemisphere, offering a wide variety of celestial objects.
- Versatility: Mount Teide is ideal for solar astronomy, nighttime astronomy, and cosmology. This diversity makes it a comprehensive center, capable of addressing everything from the Sun to the early universe.
- Conditions for outreach and education: The clear skies and infrastructure of Mount Teide facilitate astronomical outreach. The IAC organizes visits, allowing students and the general public to connect with science.
These characteristics make Teide a place comparable to the observatories of Mauna Kea (Hawaii) or the Atacama Desert (Chile), but with the advantage of being in Europe.
Sky quality at astronomical observatories in the Canary Islands
Since 1990, the Canary Islands Institute of Astrophysics (IAC) has been leading efforts to preserve this wonder through its sky quality team, created to study and protect the exceptional conditions of the skies of Tenerife and La Palma.
This team monitors key parameters, such as seeing and image sharpness, with a median of 0.7” in the Canary Islands, comparable to the best global observatories. It also designs instruments, researches atmospheric optics, and supports projects such as the Two-meter Twin Telescope (TTT) and the GREGOR solar telescope.
Their data has been vital for milestones such as the Tenerife Experiment, and for planning the future European Solar Telescope (EST).
Protecting the sky, a legal commitment
Since 1992, the Technical Office for the Protection of Sky Quality (OTPC) of the IAC has ensured compliance with the Sky Law (1988), a pioneering regulation that protects the Canary Islands observatories from four threats:
- Light pollution, regulating lighting in Tenerife and La Palma to maintain dark skies.
- Radio interference, limiting emissions that affect sensitive instruments.
- Air pollution, controlling activities that generate dust or gases.
- Air routes, preventing aircraft from interfering with the observations.
The OTPC advises on lighting projects, certifies equipment, and collaborates with agencies like AEMET to preserve the atmosphere. Its work ensures that telescopes capture sharp images under the best possible conditions.
Facilities
The observatory covers an area of about 50 hectares and has a visitor center for scientific outreach and a residence for scientific and technical staff.
Solar telescopes
Gregor Solar Telescope
The GREGOR solar telescope was built by a German consortium consisting of the Institute for Solar Physics (KIS), the Leibniz Institute for Astrophysics Potsdam (AIP), and the Max Planck Society represented by the Max Planck Institute for Solar System Research (MPS) in Göttingen.
The Institute of Astrophysics at the University of Göttingen was a member until 2008. The Canary Islands Institute of Astrophysics (IAC) and the Astronomical Institute of the Czech Academy of Sciences contributed to the telescope and instruments.
With a 1.5 m aperture, GREGOR has been in scientific operation since 2013. It is designed for high-precision measurements of the magnetic field and gas motion in the solar photosphere and chromosphere, resolving details of 70 km on the solar surface.
It also performs high-resolution stellar spectroscopy. This capability is crucial for understanding the Sun's magnetic activity, which is responsible for various phenomena and variations in its luminosity, since many important processes occur on very small spatial scales.
A large telescope like GREGOR is essential for observing these details and obtaining the precision needed to quantitatively understand the solar magnetic field. GREGOR is the largest European solar telescope for the visible and near-infrared spectral regime.
Learn more at this link: Gregor
THEMIS solar telescope
At the beginning of the 21st century, the measurement and understanding of solar magnetic fields have become central topics following important advances in the study of the internal structure of the Sun. There is growing interest in the generation, transport and behavior of magnetic fields, coronal heating, the structure of the interplanetary magnetic field, space climatology and Sun-Earth relations.
The THEMIS telescope ('Heliographic Telescope for the Study of Magnetism and Solar Instabilities') is a joint Franco-Italian project. With a 90 cm aperture, it is the third largest solar telescope in the world and is designed for high-precision, high-resolution spectropolarimetry in monochromatic imaging of the solar surface.
THEMIS features a Ritchey-Chretein design, altazimuthal mount, helium-filled tube, and a Stokes polarimeter. Its multi-mode spectrograph allows routine analysis in vector polarimetry with high precision and simultaneous observation of up to 10 wavelengths, enabling 3D inversions of the structure of the magnetic field in the solar atmosphere.
THEMIS offers three complementary observation modes: MTR (multi-line spectropolarimetry), MSDP (multi-channel spectro-imaging with polarimetry) and IPM (narrowband imaging with filters and interferometer).
THEMIS observations have revealed parasitic polarities in the magnetic fields of the filament channels and have identified depressions in the lines of magnetic force that could explain the accumulation of cold plasma at the "feet" of the filaments.
Furthermore, THEMIS has made it possible to directly measure magnetic fields in protrusions, obtaining stronger values than expected through the circular polarization of helium spectral lines.
Learn more at this link: Themis
Vacuum Tower Telescope (VTT)
The Vacuum Tower Telescope (VTT) was installed in 1986 and has been operational since 1988, belonging to four German institutions: the Potsdam Institute for Astrophysics, the Kiepenheuer Institute for Solar Physics (Freiburg, leading institution), the Max Planck Institute for Solar System Research (Lindau), and the University of Göttingen Observatory.
It is a classic solar telescope with a heliostat system of two 80cm mirrors that direct sunlight to a fixed telescope.
The main telescope has a spherical mirror with a focal length of approximately 46 m inside a 30 m vertical vacuum tank with inlet and outlet windows. The reflected light is directed downwards and then outwards into a laboratory, where a constant orientation of the solar image is maintained by the heliostat system.
The tank is evacuated to minimize internal air turbulence, and adaptive optics are used to correct image distortions caused by the Earth's atmosphere.
It conducts 30-40 observation campaigns annually between April and December. Its instrumentation allows the study of plasma flows and magnetic fields on the Sun, with simultaneous observations in different spectra and resolutions of objects up to 150 km on the solar surface, using adaptive optics.
Datos clave:
Primary mirror diameter: 70 cm
Focal length: 45.940 m
Focal ratio (f/D): 65.7
Resolution at 543.4 nm: 0.196 arcseconds
Image scale at primary focus: 4.59 arcseconds per millimeter
Learn more at this link: VTT
Nighttime telescopes
IAC-80
The IAC80 telescope, designed and built by the IAC, was the first of its kind in Spain and was installed at the Teide Observatory in 1991.
With an 82cm primary mirror and configured for optical observations, it is ideal for long-term programs, collaborations, urgent observations, student practices, and instrumentation testing.
Equipped with the CAMELOT2 camera, the IAC80 also serves as a testbed for instrumentation of larger telescopes (such as the GTC), for the atmospheric characterization of the Canary Islands observatories and for the training of university students.
Its versatility and availability make it a key component of the Teide Observatory. The IAC80 has made significant contributions to astronomy with over 100 publications.
His varied observations range from comets (such as Shoemaker-Levy 9) to quasars and gravitational lenses. Highlights include the discovery of Teide 1 (the first brown dwarf), the study of a gravitational lens that yielded data on dark matter, and the imaging of the source of a powerful gamma-ray burst.
Carlos Sanchez Telescope (TCS)
The Carlos Sánchez Telescope (TCS), with a 1.52-meter mirror, is configured primarily for nighttime infrared observations. Designed by J. Ring and built in collaboration between the United Kingdom and the IAC, it was commissioned in 1972 after being installed in Tenerife in 1971.
Initially conceived as a low-cost flux collector, it was one of the first thin-mirror telescopes. In 1983, the SERC transferred ownership to the IAC, which carried out improvements in maintenance, automation, and instrumentation.
The telescope was named in honor of Dr. Carlos Sánchez Magro, professor of astrophysics at the University of La Laguna and a key figure at the IAC, especially in promoting infrared astronomy.
The TCS is ideal for observing "cold" objects such as early or late evolving stars, and obtained early infrared images of the impact of comet Shoemaker-Levy 9 on Jupiter and of substellar objects. It often collaborates with other telescopes at the Teide Observatory (OGS and IAC80) for complementary observations.
He has produced nearly 250 scientific articles, with projects ranging from mapping the galactic center to studying stellar oscillations.
Some highlights include the creation of the first catalog of star-forming galaxies in the H band, the photometry of asteroid 2002 NY40, and the photometric study of Orion clusters that identified low-mass stars and possible brown dwarfs.
MONS reflector telescope
The MONS telescope is a 50 cm reflector built by the University of Mons (Belgium) in 1972 for nighttime observation. Initially used for practical exercises by the Astrophysics Department of the University of La Laguna, its primary use remains teaching, and it is frequently requested by various universities and amateur astronomy groups for practical activities.
OGS Telescope
STELLA
STELLA (Stella Robotic Observatory) is a long-term project launched in 2006 with two 1.2m robotic telescopes dedicated to observing activity in cool stars, using a high-resolution spectrograph (SES) and a wide-field imager (WiFSIP).
It stands out for its operational efficiency, with a technical downtime of only 2% and high shutter opening times (87.5% for SES and 67.9% for WiFSIP). This is achieved through the parallel execution of tasks, such as panning and acquiring the next subject while reading the previous exposure.
The STELLA control system (SCS), a general-purpose software for optical telescopes, uses an XML-based meta-language to design new observing strategies. The programming is based on a dispatch scheme that optimizes the selection of observations from a large group using a "greedy" heuristic.
Both telescopes, STELLA-I and STELLA-II, were manufactured by Halfmann Teleskoptechnik and feature Alt/Az mounts. STELLA-I has an f/8 system with two Nasmyth focal points and a 30' field of view. The telescopes utilize hydrostatic and ball bearings and are driven by ETEL direct drive motors with Heidenhain encoders, achieving high pointing and tracking accuracy.
Learn more at this link: STELLA
SONG
SONG (Stellar Observations Network Group) is a Danish project, initiated in 2006 by the universities of Aarhus and Copenhagen, to build a global network of small, robotic telescopes to study stars and planetary systems.
The goal was to create a modern, cost-effective telescope with significant scientific impact. The 1.0 m Cassegrain telescope, manufactured by ASTELCO Systems GmbH with an alt-az mount, boasts a high rotation speed (20°/s) and pointing accuracy (<3" RMS). Its thin primary mirror is actively controlled.
Equipped with two Nasmyth focal points, the telescope is remotely controlled and its installation cost was relatively low (30 million Danish kroner). SONG's uniqueness lies in its instrumentation and the planned global network of eight telescopes.
SONG's scientific objectives are:
- Studying the internal structure and evolution of stars through asteroseismology.
- Search for and characterize planets with masses comparable to Earth orbiting other stars.
Two-meter Twin Telescope (TTT)
It is a revolutionary astronomical project that combines cutting-edge robotic technology with an ambitious scientific approach. Operated by the company Light Bridges in collaboration with the Instituto de Astrofísica de Canarias (IAC), it comprises four telescopes: two 80 cm telescopes (TTT1 and TTT2, fully operational since December 2022) and two 2-meter telescopes (TTT3, which achieved first light in February 2025, and TTT4, currently under construction).
This complex represents a milestone in modern astronomy, both for its technological innovation and its public-private funding model.
The TTT is designed to tackle some of the universe's greatest mysteries with unprecedented efficiency. Its robotic telescopes operate autonomously, using the Queue Planning Intelligent System (QPIS), software based on machine learning algorithms that optimizes the selection of observations in real time.
This system allows scientific proposals to be evaluated in just 48 hours and astrometrically and photometrically calibrated images to be delivered in 24 hours, making it an ideal tool for research that requires quick answers, such as the detection of supernovae or transient events.
This project is important because it covers a wide range of research:
- Transient events: Detect fleeting phenomena such as supernovae and gamma ray bursts (GRBs), as well as electromagnetic counterparts of gravitational waves, essential to understanding the most energetic events in the universe.
- Exoplanets: Characterizing new worlds and their systems, contributing to the search for habitable planets and the study of planetary formation.
- Black Holes: Conduct surveys to detect and analyze black holes, unraveling their role in cosmic evolution.
- Trans-Neptunian Objects (TNOs): Studying the morphology of these distant bodies through stellar occultations, offering clues about the origins of the Solar System.
- Minor Bodies: Detecting and characterizing comets and asteroids, with special attention to NEOs (near-Earth asteroids), including the dangerous “city killers.” The TTT also analyzes the physical properties (size, shape, composition, rotation) and dynamics of asteroids to assess their potential impact on Earth.
- Solar Stars: Investigating the variability and activity cycles in Sun-like stars is key to understanding stellar evolution.
- Low-luminosity structures: Taking advantage of the TTT's wide field of view to study stellar halos, ultra-diffuse galaxies and intracluster light, revealing subtle structures of the universe.
- Space debris: Detecting and tracking satellites and orbital debris, a critical area for space safety.
Teide Observatory Solar Laboratory
The Solar Laboratory at the Teide Observatory (IAC) operates continuously with six instruments dedicated to a unique scientific program that has been running for over 25 years, both day and night. Although the instruments belong to various institutions, the IAC's "Solar and Stellar Seismology and Exoplanet Search" group operates them and participates in their scientific exploitation through international consortia.
The main objective is the study of the solar interior through helioseismology, recently expanded to include asteroseismology, detection of exoplanets and measurement of the Earth's albedo.
The IAC helioseismology group pioneered the discovery of the global nature of 5-minute solar oscillations in 1979. The first instrument was installed in 1976, providing unique data on the sensitivity of solar pulsations to the solar activity cycle.
In 1981, the viability of the "Observational Network" was demonstrated by combining data from similar instruments at different locations, significantly improving data quality. Since 1983, the Solar Laboratory has made continuous contributions to globally used helioseismological databases.
The lines of research include the development of instruments to study the solar background spectrum and detect gravitational modes, improve helioseismological data to study the solar tachocline, make precise measurements of the frequencies of acoustic modes to infer the internal structure and rotation of the Sun, detect subsurface matter flows through local seismology, study the thermodynamics of the photosphere and analyze the correlations between helioseismological parameters and solar activity to understand the solar dynamo.
From that first telescope in 1964 to the advanced robotic telescopes of the Two-meter Twin Telescope (TTT), the Teide Observatory has been much more than a place of science: it is a bridge between the Canary Islands and the cosmos. Here, the cosmic microwave background told us about the Big Bang, we discovered the brown dwarf Teide 1, and we tracked comets that marked history.
Today, Teide continues to look to the future; through school visits and outreach, the Canary Islands Institute of Astrophysics (IAC) brings the universe closer to everyone.
Visit Mount Teide, marvel at its sky and join this adventure that, from Tenerife, illuminates the secrets of infinity.
If you want to learn more about the observatory, its studies, news, or simply expand your knowledge, you can visit the official website of the IAC as well as the website of IAC Canary Islands Observatories.
