Road to astronomers’ paradise

The southern sky and the Milky Way is photographed in the morning twilight above a road approaching the European Southern Observatory (ESO) site of Cerro Paranal, in the Atacama Desert, Chile. At 2,635 meters (8,645 ft) from sea level, with its dark and transparent sky, Paranal is home to some of the world’s leading telescopes. On top is the Very Large Telescope (VLT); composed of four 8-metre telescopes.

Image credit: Christoph Malin

En diciembre del año 2012, y gracias al telescopio VLT , se descubrió el quásar con la salida más energética que se había visto hasta ahora.

El telescopio VLT pertenece al Observatorio Europeo del Sur y está ubicado en el cerro Paranal, una montaña situada en el desierto de Atacama, al norte de Chile.

Esta potentísima salida energética se encuentra a unos mil años luz de un agujero negro súpermasivo, justo en el centro del quásar , que se mueve a una velocidad de 8.000 kilómetros por segundo. El tipo de energía que expulsa a alta velocidad es como mínimo equivalente a dos millones de millones de veces la potencia de salida del Sol. Más concretamente, es aproximadamente 100 veces mayor que la potencia total de la galaxia de la Vía Láctea.

Imagen de Astronomía en tu bolsillo


Four Lasers Over Paranal

First light for the Four Laser Guide Star Facility on ESO’s Very Large Telescope

On 26 April 2016 ESO’s Paranal Observatory in Chile hosted an event to mark the first light for the four powerful lasers that form a crucial part of the adaptive optics systems on ESO’s Very Large Telescope. Attendees were treated to a spectacular display of cutting-edge laser technology against the majestic skies of Paranal. These are the most powerful laser guide stars ever used for astronomy and the event marks the first use of multiple laser guide stars at ESO.

ESO staff were present for the event, along with senior representatives of the companies that have manufactured the different components of the new system.

The Four Laser Guide Star Facility (4LGSF) shines four 22-watt laser beams into the sky to create artificial guide stars by making sodium atoms in the upper atmosphere glow so that they look just like real stars [1]. The artificial stars allow the adaptive optics systems to compensate for the blurring caused by the Earth’s atmosphere and so that the telescope can create sharp images. Using more than one laser allows the turbulence in the atmosphere to be mapped in far greater detail to significantly improve the image quality over a larger field of view.

The Four Laser Guide Star Facility is an example of how ESO enables European industry to lead complex research and development projects. The fibre laser used by the 4LGSF is also one of the most successful transfers of ESO technology to industry.

TOPTICA, the German main contractor, was responsible for the laser system and provided the oscillator, the frequency doubler, and the system control software. Wilhelm Kaenders, president of TOPTICA, said: “TOPTICA has enjoyed the collaboration with ESO tremendously. It is not only the personal thrill of being engaged with astronomy, an old passion, again, and working with very clever ESO technologists; it is also the inspiration that we have received for our own commercial product development.” [2]

MPBC of Canada provided the fibre laser pumps and Raman amplifiers, which are based on an ESO licensed patent. Jane Bachynski, President of MPB Communications Inc. said: “MPBC is proud to have worked with ESO in the development of Raman fibre amplifiers to much higher powers, allowing MPBC to bring this technology to the stars. This event marks the culmination of many years of hard work on behalf of all involved.” [3]

TNO in the Netherlands manufactured the optical tube assemblies, which expand the laser beams and direct them into the sky. Paul de Krom, CEO of TNO, said: “TNO valued the cooperative working environment during the development of the optical tube assemblies and looks forward to the opportunity to work with ESO and the other partners in the 4LGSF project in the future.” [4]

The 4LGSF is part of the Adaptive Optics Facility on Unit Telescope 4 of the VLT, designed specifically to provide the adaptive optics systems GALACSI/MUSE and GRAAL/HAWK-I with four sodium laser guide stars. With this new facility, Paranal Observatory continues to have the most advanced and the largest number of adaptive optics systems in operation today.

The 4LGSF lasers were developed by ESO with industry and have already been procured, among others, by the Keck Observatory (which contributed to the industrial laser development cost along with the European Commission) and the Subaru Telescope. In the future these industrial lasers will also feature on the telescopes at the Gemini Observatory and will be the preferred choice for several other observatories and extremely large telescope projects.

The new techniques developed for the Four Laser Guide Star Facility pave the way for the adaptive optics system of the European Extremely Large Telescope (E-ELT), the world’s biggest eye on the sky.


[1] The 4LGSF is the second generation laser guide star facility, built by ESO for the Adaptive Optics Facility on the UT4 VLT telescope. The two critical long-lead items for the 4LGSF, the laser system and the optical tube assemblies for the laser launch telescope systems have been procured from industry. The fibre Raman laser technology, on which the 4LGSF laser system is based, has been developed at ESO, patented and licensed to industry.

[2] This project has allowed TOPTICA to extend its products into a new wavelength and output power regime. It now produces the SodiumStar 20/2, which is recognised as a quasi-standard for existing and planned telescopes around the world. All next generation extremely large telescope projects, for example, use the SodiumStar laser as their baseline. During the seven years of collaboration with ESO the company has grown from 80 people to more than 200 today.

[3] MPBC’s collaboration with ESO has also generated an additional benefit, in the form of an offshoot product line of single frequency amplification products at virtually any wavelength, supporting novel applications for the scientific and commercial research community.

[4] The developments by TNO also involved contributions from many suppliers from the Netherlands (Vernooy, Vacutech, Rovasta, Schott Benelux, Maxon Motor Benelux, IPS technology, Sensordata and WestEnd) and other international companies (RMI, Qioptiq, Laser Components, Carl Zeiss, GLP, Faes, Farnell, Eriks and Pfeiffer). The knowledge and technologies advanced by working with ESO feed into TNO’s Dutch and European partners, in fields including astronomy, communications, semiconductor manufacturing, medical devices, space science and Earth observation.

More information

ESO is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive ground-based astronomical observatory by far. It is supported by 16 countries: Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom, along with the host state of Chile. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope, the world’s most advanced visible-light astronomical observatory and two survey telescopes. VISTA works in the infrared and is the world’s largest survey telescope and the VLT Survey Telescope is the largest telescope designed to exclusively survey the skies in visible light. ESO is a major partner in ALMA, the largest astronomical project in existence. And on Cerro Armazones, close to Paranal, ESO is building the 39-metre European Extremely Large Telescope, the E-ELT, which will become “the world’s biggest eye on the sky”.


A new study has revealed similarities and relationships between certain types of chemicals found on 30 different comets, which vary widely in their overall composition compared to one another. The research is part of ongoing investigations into these primordial bodies, which contain material largely unchanged from the birth of the solar system some 4.6 billion years ago.

By studying the composition of hazy comas and tails of these comets, researchers found that certain chemical ices on the comets would regularly appear in concert with other chemicals in a correlated way, while certain other chemicals appeared or were absent independently from others. “This relates to how the chemicals are stored together or sequestered in the nucleus, or body of the comet,” said the paper’s lead author, Neil Dello Russo, a space scientist at the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland.

The amounts and relationships of the chemicals observed in comets can help researchers understand more about the formation of our solar system. “We want to study the abundances of these chemicals because comets are a window into the distant past, and they can tell us what the chemical characteristics and conditions were like in the early solar system,” said Dello Russo. The team studied various types of simple but abundant chemicals, including volatiles such as water, methane, carbon monoxide and ammonia. Observations from Earth cannot directly detect these chemicals on the nucleus of comets, but gases, ices and grains released from the comet leave a chemical trail that can be observed in the hazy comas and tails of comets.

Researchers studied data gathered from 1997 to 2013, and included both short-period comets (those that are stored around the Kuiper belt beyond the gas giant planets) and long-period comets (which formed among the gas giants before they were ejected to the far more distant Oort cloud). The study compared the chemical makeup of the comets measured after they were released from these reservoirs and found that while each comet has a unique chemical signature, short-period comets are on average more depleted in certain chemicals than long-period comets from the Oort cloud.

The findings were published in the November issue of Icarus.

The study utilized Earth-based high-resolution infrared spectrometers, which can observe minute differences in color that reveal diagnostic fingerprints of the chemicals present in comet tails. Data from the Near-Infrared Spectrometer (NIRSPEC) at the Keck 2 Telescope of the W. M. Keck Observatory on Maunakea, Hawaii; the Cryogenic Echelle Spectrometer (CSHELL) at the NASA Infrared Telescope Facility on Maunakea; the Infrared Camera and Spectrograph at the Subaru telescope, also on Maunakea; and the CRyogenic high-resolution InfraRed Echelle Spectrograph (CRIRES) spectrometer at the VLT Telescope at Cerro Paranal, Chile, were used.

Dello Russo explained that this research was only made possible due to recent breakthroughs in infrared spectrometers: “In the past 20 years, technological advances have really made it possible to accurately detect volatile chemicals in comets, and to do so for comets that are fainter and farther away than previously possible. That allowed us to study a large enough group of comets to note and examine significant trends.”

Dello Russo said that studies such as these are needed to expand what scientists know about the nature and history of comets, how cometary ices are related, and how they are stored in and released from the nucleus. “Comets are very diverse,” he said. “When NASA or ESA sends a mission to a comet, we can learn a tremendous amount of detail on that specific comet. What our research does is put those findings into the larger chemical context of the overall comet population. We can help answer where an individual comet fits into the population of comets.”

IMAGE….This NASA/ESA Hubble Space Telescope image of comet 73P/Schwassmann-Wachmann 3 disintegrating in 2006 shows the tails and comas of the individual pieces of the comet; new research on comet composition included infrared spectrography of this comet during its breakup.
Image credit: NASA, ESA, H. Weaver (APL), M. Mutchler and Z. Levay (STScI)

An emu in the sky over Paranal

Sitting atop Cerro Paranal high above the Atacama Desert in Chile, two of the Very Large Telescope’s Unit Telescopes quietly bask in the starlight, observing the Milky Way as it arches over ESO's Paranal Observatory.

Several interesting objects can be seen in this picture. Some of the most prominent are the two Magellanic Clouds — one Small (SMC), one Large (LMC) — which appear brightly in between the two telescopes. By contrast, the dark Coalsack Nebula can be seen as an obscuring smudge across the Milky Way, resembling a giant cosmic thumbprint above the telescope on the left.

The Magellanic Clouds are both located within the Local Group of galaxies that includes our galaxy, the Milky Way. The LMC lies at a distance of 163 000 light-years from our galaxy, and the SMC at 200 000 light-years. The Coalsack Nebula, on the other hand, is a mere stone’s throw away in comparison. At roughly 600 light-years from the Solar System, it is the most visible dark nebula in our skies.

The Coalsack has been recorded by many ancient cultures, and is identified as the head of the Emu in the Sky by several indigenous Australian groups. Aboriginal Australians are most likely the oldest practitioners of astronomy in the world, and they identify their constellations by use of dark nebulae — as opposed to stars, as is the Western tradition.

In the Southern hemisphere, these dark clouds are more prominent than in the Northern sky. Other cultures also had dark constellations — for example, the Inca in South America. A particularly important constellation to the Inca astronomers was one known as Urcuchillay (The Llama), representing the significance of the animals in their culture as a source of food, wool, and transport.

Image credit: ESO/Y. Beletsky

Morning light over La Silla

Here we see ESO's La Silla Observatory with a backdrop of the Milky Way. Established in the 1960s, La Silla was ESO’s first observatory to be built in Chile.

Visible on the hill in the centre of this image is the rectangular New Technology Telescope (NTT) on the left, and the domed ESO 3.6-metre telescope to the right. The 3.58-metre NTT was inaugurated in 1989, and was the first in the world to have a computer-controlled main mirror. The main mirror is flexible, and its shape is actively adjusted during observations to preserve the optimal image quality. This technology, known as active optics, is now applied to all major modern telescopes — including the Very Large Telescope at Cerro Paranal, and the future European Extremely Large Telescope.

La Silla is home to several other telescopes, including the Swedish–ESO Submillimetre Telescope (SEST), and the robotic TAROT, which is used to monitor rapidly occurring events such as gamma-ray bursts.

This picture was taken by ESO Photo Ambassador José Joaquín Pérez. When José is not taking stunning photos of the night sky, he works as an agricultural engineer where he devotes his time to the protection of crops in central Chile.

Image credit: ESO/J. Pérez

Orion Nebula and the Horsehead

The Orion Nebula, the Flame, and the Horsehead dark nebula, framed with the Belt of Orion (the three aligned stars on the right), in a telephoto image. The image is achieved by a single exposure. Generally this kind of deep night sky images were used to be composite images resulted of various exposures but thanks to the pristine conditions at Paranal and the advanced camera technology this image was doable by classic single exposure photography. The photographer has also used a skyglow filter (for DSLR cameras) to increase the nebulosity contrast. In the foreground is one of the telescopes on the Cerro Paranal Observatory in the Atacama Desert, Chile. With its dark and transparent sky, Paranal is home to the Very Large Telescope (VLT), operated by the European Southern Observatory (ESO). It is composed of four 8-metre telescopes and smaller auxiliary telescopes, each 1.8 metres in aperture (pictured here) which are important elements of the VLT interferometer.

Image credit: Babak A. Tafreshi

The snows of Paranal

This dawn portrait of snowy mountain and starry sky captures a very rare scenario. The view does feature a pristine sky above the 2,600 meter high mountain Cerro Paranal, but clear skies over Paranal are not at all unusual. That’s one reason the mountain is home to the European Southern Observatory's Very Large Telescope. Considering the number of satellites now in orbit, the near sunrise streak of a satellite glinting at the upper left isn’t rare either. And the long, bright trail of a meteor can often be spotted this time of year too. The one at the far right is associated with the annual Perseid meteor shower. In fact, the rarest aspect of the picture is just the snow. Cerro Paranal rises above South America’s Atacama desert, known as the driest place on planet Earth.

Image credit & copyright: Yuri Beletsky (ESO)

An oasis or a secret lair?

This image shows a dark Chilean sky filled with spectacular star trails — caused by the Earth’s rotation during the camera’s long exposure time. Underneath these dramatic streaks lies the Paranal Residencia, an oasis to the staff and visitors to ESO's Very Large Telescope, located high on Cerro Paranal in the Chilean desert.

Construction of the Residencia began in 1998 and was completed by 2002. Since then, it has offered a welcome break from the harsh, dry climate of the desert to the scientists and engineers who work at Paranal Observatory.

The four-story building has the majority of its structure buried underground. The facility was designed by German architects Auer+Weber to complement the surrounding environment. From certain angles, the combination of hi-tech utilitarian architecture and inconspicuous, almost camouflage-like design is reminiscent of a villain’s secret lair. Perhaps it is no surprise that the Residencia was selected as the setting for the final battle in the 2008 James Bond movie Quantum of Solace.

Image credit: John Colosimo/ ESO


Astronomer’s Paradise

by Christoph Malin