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  • richardmitnick 8:30 pm on July 26, 2018 Permalink | Reply
    Tags: AOF- Adaptive Optics Facility, , , , , , , , Reinhard Genzel,   

    From Max Planck Max Planck Institute for Extraterrestrial Physics: ” ‘The galactic centre offers fantastic opportunities’” 

    From Max Planck Max Planck Institute for Extraterrestrial Physics

    July 26, 2018

    Prof. Dr. Reinhard Genzel
    Max Planck Institute for Extraterrestrial Physics, Garching
    +49 89 30000-3280 genzel@mpe.mpg.de

    Helmut Hornung
    Administrative Headquarters of the Max Planck Society, München
    +49 89 2108-1404 hornung@gv.mpg.de

    It is highly likely that there is a black hole at the centre of the Milky Way. The astronomers working under Reinhard Genzel, Director of the Max Planck Institute for Extraterrestrial Physics in Garching near Munich are making repeated detailed studies of the surrounding area of the gravitational trap. Now, the researchers have succeeded in making a huge achievement in the art of observation: from the motion of a star called S2 around the black hole, which is 26,000 light years away, they have measured an effect predicted by Albert Einstein known as the gravitational redshift. What is so special about this observation?

    Star S2 Keck/UCLA Galactic Center Group

    1
    The astronomer and his tool: Reinhard Genzel, Director at the Max Planck Institute for Extraterrestrial Physics, in front of the Very Large Telescope, which he uses to peer into the heart of the Milky Way.
    © MPE

    ESO VLT at Cerro Paranal in the Atacama Desert, elevation 2,635 m (8,645 ft) from above Credit J.L. Dauvergne & G. Hüdepohl atacama photo

    You have been studying the surrounding area of the black hole in the centre of the Milky Way for more than 20 years. Were you specifically looking for the gravitational redshift that you have now discovered, or did this happen by accident?

    No, the discovery was by no means accidental. We’ve been systematically looking for this and preparing the experiment for ten years now. We’ve known for a long time that the object in the galactic centre has a very high mass, and that it is highly plausible that it is a black hole. However, there’s a difference between plausibility and physical certainty. That’s why we design all kinds of tests, for which the centre of our Milky Way offers wonderful opportunities. In short: our current measurement of the gravitational redshift is already providing very strong evidence of the existence of the black hole in the galactic centre – and of the general theory of relativity.

    The current observations are taking place on the margins of what is measurable. What instruments did you need in order to achieve your successful result?

    Certainly, measurements like these would not have been possible just a few years ago. At that time, we observed the centre of the Milky Way using a single eight-meter mirror in the Very Large Telescope. Now, we us all four telescopes in the system in Chile at the same time by using interferometry.

    ESO VLT Interferometer, at Cerro Paranal, with an elevation of 2,635 metres (8,645 ft) above sea level

    In radio astronomy, this procedure, in which the waves of an object overlap and this appears sharper as a result, has already been established for decades, but not in the field of optics. For this reason, the Max Planck Institute for Extraterrestrial Physics headed by Frank Eisenhauer, together with the Max Planck Institute for Astronomy, the European Southern Observatory, the University of Cologne, two French CNRS institutes and institutes in Porto and Lisbon, has developed a highly complex instrument called Gravity.

    ESO GRAVITY in the VLTI

    Gravity processes the signals of the four individual telescopes and offers a huge improvement in the detail resolution in the infrared range. This means that thanks to Gravity, the Very Large Telescope could in theory provide images of two adjacent two-euro coins on the moon. It’s no exaggeration to say that Gravity has led to a breakthrough in the field of optics in matters relating to interferometry.

    A key role during observation is probably also played by adaptive optics. What’s the reason for this?

    Glistening against the awesome backdrop of the night sky above ESO_s Paranal Observatory, four laser beams project out into the darkness from Unit Telescope 4 UT4 of the VLT.

    Turbulences in the Earth’s atmosphere distort the wavefronts of the stars’ light. In principle, the aim is to compensate the crests and troughs of waves. This is made possible through the use of a mirror in the telescope, which has mechanical tappets attached to its rear side. These so-called actuators deform the surface of this small mirror in the beam path up to a thousand times per second, and in this way eliminate the distortions. In this way, we achieve the theoretical resolution of the telescope – and this is higher by a factor of ten than those that are achieved without correcting the air turbulence.

    You said that the centre of the Milky Way offers wonderful opportunities to finally put the general theory of relativity to the test …

    … and the redshift measured by us is one of these tests. In this regard, it’s important to realise that such a redshift is not just caused by the Doppler effect. We know this from everyday life when for example an ambulance drives past us, and the tone level of the siren increases and decreases. At the same time, this means a displacement of the wavelength into the short- or long-wave range. This also occurs with light waves, where reference is made to blueshift or also redshift. This aside, according to the general theory of relativity, a redshift also occurs in the field of gravity when light moves there and fights against it to a certain degree. This effect also has an impact on the radiation of the S2 star, which approaches the black hole up to a distance of around 14 billion kilometres – which is the equivalent of three times the distance between the planet Neptune and the Sun. On 19 May of this year, S2 again passed the place where the distance was lowest during its orbit. For us, this offered a unique opportunity to measure the gravitational redshift.

    Can you foresee conducting further tests for the general theory of relativity?

    Yes, another test would be the Schwarzschild precession. This sounds complicated, but in fact, it’s simple. According to the general theory of relativity, celestial bodies that move around a central mass do not run on closed trajectories. The point of the greatest approximation, the perihelion, constantly continues to move in space. This can be clearly observed with planet Mercury, the perihelion rotation of which has been known for a long time. Its measured value correlates precisely with Einstein’s prediction. It is likely that a similar effect can be observed in the orbits of stars that move around the central black hole of the Milky Way. Indeed, we are already seeing the first signs of this. In two years’ time, we should then have statistically significant measurements. The best test for the general theory of relativity would otherwise be when a star falls into the black hole in front of our eyes. Unfortunately, statistically speaking, this happens only once every 10,000 years.

    The gravitation effect measured by your group is a wonderful piece of evidence supporting Einstein’s theory of relativity. Is there any doubt at all now about the validity of this theory?

    Yes, certainly! To put it in drastic terms: the physical laws known to us to date only apply to a limited range of parameters. The tiniest and the largest in particular, namely quantum physics and the theory of relativity, do not match each other. And so far, a corresponding quantum theory of gravitation has not yet been developed.

    Interview: Helmut Hornung

    See the full article here .

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    For their astrophysical research, the MPE scientists measure the radiation of far away objects in different wavelenths areas: from millimetere/sub-millimetre and infared all the way to X-ray and gamma-ray wavelengths. These methods span more than twelve decades of the electromagnetic spectrum.

    The research topics pursued at MPE range from the physics of cosmic plasmas and of stars to the physics and chemistry of interstellar matter, from star formation and nucleosynthesis to extragalactic astrophysics and cosmology. The interaction with observers and experimentalists in the institute not only leads to better consolidated efforts but also helps to identify new, promising research areas early on.

    The structural development of the institute mainly has been directed by the desire to work on cutting-edge experimental, astrophysical topics using instruments developed in-house. This includes individual detectors, spectrometers and cameras but also telescopes and integrated, complete payloads. Therefore the engineering and workshop areas are especially important for the close interlink between scientific and technical aspects.

    The scientific work is done in four major research areas that are supervised by one of the directors:

    Center for Astrochemical Studies (CAS)
    Director: P. Caselli

    High-Energy Astrophysics
    Director: P. Nandra

    Infrared/Submillimeter Astronomy
    Director: R. Genzel

    Optical & Interpretative Astronomy
    Director: R. Bender

    Within these areas scientists lead individual experiments and research projects organised in about 25 project teams.

    The Max Planck Society is Germany’s most successful research organization. Since its establishment in 1948, no fewer than 18 Nobel laureates have emerged from the ranks of its scientists, putting it on a par with the best and most prestigious research institutions worldwide. The more than 15,000 publications each year in internationally renowned scientific journals are proof of the outstanding research work conducted at Max Planck Institutes – and many of those articles are among the most-cited publications in the relevant field.

    What is the basis of this success? The scientific attractiveness of the Max Planck Society is based on its understanding of research: Max Planck Institutes are built up solely around the world’s leading researchers. They themselves define their research subjects and are given the best working conditions, as well as free reign in selecting their staff. This is the core of the Harnack principle, which dates back to Adolph von Harnack, the first president of the Kaiser Wilhelm Society, which was established in 1911. This principle has been successfully applied for nearly one hundred years. The Max Planck Society continues the tradition of its predecessor institution with this structural principle of the person-centered research organization.

    The currently 83 Max Planck Institutes and facilities conduct basic research in the service of the general public in the natural sciences, life sciences, social sciences, and the humanities. Max Planck Institutes focus on research fields that are particularly innovative, or that are especially demanding in terms of funding or time requirements. And their research spectrum is continually evolving: new institutes are established to find answers to seminal, forward-looking scientific questions, while others are closed when, for example, their research field has been widely established at universities. This continuous renewal preserves the scope the Max Planck Society needs to react quickly to pioneering scientific developments.

     
  • richardmitnick 11:08 am on January 31, 2018 Permalink | Reply
    Tags: AOF- Adaptive Optics Facility, , , , , ESO GRAAL, , , Sharper Images for VLT Infrared Camera   

    From ESO: “Sharper Images for VLT Infrared Camera” 

    ESO 50 Large

    European Southern Observatory

    30 January 2018
    Harald Kuntschner
    ESO, AOF Project Scientist
    Garching bei München, Germany
    Tel: +49 89 3200 6465
    Email: hkuntsch@eso.org

    Richard Hook
    ESO Public Information Officer
    Garching bei München, Germany
    Tel: +49 89 3200 6655
    Cell: +49 151 1537 3591
    Email: rhook@eso.org

    1
    This image of the dramatic star formation region 30 Doradus, also known as the Tarantula Nebula, was created from a mosaic of images taken using the HAWK-I instrument working with the Adaptive optics Facility of ESO’s Very Large Telescope in Chile. The stars are significantly sharper than the same image without adaptive optics being used, and fainter stars can be seen.

    ESO’s Very Large Telescope (VLT) now has a second instrument working with the powerful Adaptive Optics Facility (AOF). The infrared instrument HAWK-I (High Acuity Wide-field K-band Imager) [1] is now also benefiting from sharper images and shorter exposure times. This follows the successful integration of the AOF with MUSE (the Multi Unit Spectroscopic Explorer).

    ESO HAWK-I on the ESO VLT

    ESO MUSE on the VLT

    The Adaptive Optics Facility (AOF) is a long-term project that is nearing completion on ESO’s Very Large Telescope (VLT). It provides adaptive optics correction for all the instruments attached to one of the VLT Unit Telescopes (UT4, also known as Yepun).

    ESO VLT AOF new laser at Cerro Paranal, with an elevation of 2,635 metres (8,645 ft) above sea level

    Adaptive optics works to compensate for the blurring effect of the Earth’s atmosphere. This upgrade now enables HAWK-I to obtain sharper images, needing shorter exposure times than before to obtain similar results. By using the AOF, astronomers can now get good image quality with HAWK-I, even when the weather conditions are not perfect.

    Following a series of tests of the new system, the commissioning team of astronomers and engineers were rewarded with a series of spectacular images, including one of the Tarantula Nebula star-forming region in the Large Magellanic Cloud.

    The AOF, which made these observations possible, is composed of many parts working together. These include the Four Laser Guide Star Facility (4LGSF) and the UT4’s very thin deformable secondary mirror, which is able to change its shape [2] [3]. The 4LGSF shines four 22-watt laser beams into the sky to make sodium atoms in the upper atmosphere glow as bright points of light, forming artificial guide stars.

    Sensors in the adaptive optics module GRAAL (GRound layer Adaptive optics Assisted by Lasers) use these artificial guide stars to determine the atmospheric conditions.

    ESO Graal

    One thousand times per second, the AOF system calculates the correction that must be applied to the telescope’s deformable secondary mirror to compensate for the atmospheric disturbance.

    GRAAL corrects for the turbulence in the layer of atmosphere up to about 500 metres above the telescope — the “ground layer”. Depending on the conditions, atmospheric turbulence occurs at all altitudes, but studies have shown that the largest fraction of the disturbance occurs in the ground layer of the atmosphere.

    The corrections applied by the AOF rapidly and continuously improve the image quality by concentrating the light to form sharper images, allowing HAWK-I to resolve finer details and detect fainter stars than previously possible.

    MUSE and HAWK-I are not the only instruments that will benefit from the AOF; in future, the new instrument ERIS will be installed on the VLT. The AOF is also a pathfinder for adaptive optics on ESO’s Extremely Large Telescope (ELT).

    Notes

    [1] HAWK-I is a wide-field imager, an instrument that takes images of the sky in infrared wavelengths. This allows it to see inside interstellar dust and gas, which blocks optical light. The instrument uses four imaging chips simultaneously to achieve such a large field of view, capturing a wealth of information.

    [2] At just over one metre in diameter, this is the largest adaptive optics mirror in operation and demanded cutting-edge technology to make it. It was mounted on UT4 in 2016 (ann16078) to replace the telescope’s original conventional secondary mirror.

    [3] Other tools to optimise the operation of the AOF have been developed and are now operational. These include an extension of the Astronomical Site Monitor software that monitors the atmosphere to determine the altitude at which the turbulence is occurring, and the Laser Traffic Control System (LTCS) that prevents other telescopes looking into the laser beams or spots and potentially affecting their observations.

    See the full article here .

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    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”.

    ESO LaSilla
    ESO/Cerro LaSilla 600 km north of Santiago de Chile at an altitude of 2400 metres.

    ESO VLT
    VLT at Cerro Paranal, with an elevation of 2,635 metres (8,645 ft) above sea level.

    ESO Vista Telescope
    ESO/Vista Telescope at Cerro Paranal, with an elevation of 2,635 metres (8,645 ft) above sea level.

    ESO NTT
    ESO/NTT at Cerro LaSilla 600 km north of Santiago de Chile at an altitude of 2400 metres.

    ESO VLT Survey telescope
    VLT Survey Telescope at Cerro Paranal with an elevation of 2,635 metres (8,645 ft) above sea level.

    ALMA Array
    ALMA on the Chajnantor plateau at 5,000 metres.

    ESO E-ELT
    ESO/E-ELT to be built at Cerro Armazones at 3,060 m.

    ESO APEX
    APEX Atacama Pathfinder 5,100 meters above sea level, at the Llano de Chajnantor Observatory in the Atacama desert.

    Leiden MASCARA instrument, La Silla, located in the southern Atacama Desert 600 kilometres (370 mi) north of Santiago de Chile at an altitude of 2,400 metres (7,900 ft)

    Leiden MASCARA cabinet at ESO Cerro la Silla located in the southern Atacama Desert 600 kilometres (370 mi) north of Santiago de Chile at an altitude of 2,400 metres (7,900 ft)

    ESO Next Generation Transit Survey at Cerro Paranel, 2,635 metres (8,645 ft) above sea level

    SPECULOOS four 1m-diameter robotic telescopes 2016 in the ESO Paranal Observatory, 2,635 metres (8,645 ft) above sea level

    ESO TAROT telescope at Paranal, 2,635 metres (8,645 ft) above sea level

    ESO ExTrA telescopes at Cerro LaSilla at an altitude of 2400 metres

     
  • richardmitnick 3:38 pm on September 15, 2017 Permalink | Reply
    Tags: AOF- Adaptive Optics Facility, , , , ,   

    From ESOblog: “Behind the scenes of the Adaptive Optics Facility” 

    ESO 50 Large

    ESOblog

    If you’ve ever visited ESO’s website or checked our social media, you’ve probably seen an impressive picture of the Very Large Telescope at the Paranal Observatory, with four brilliant laser beams shooting up into the night sky.

    2
    Glistening against the awesome backdrop of the night sky above ESO’s Paranal Observatory, four laser beams project out into the darkness from Unit Telescope 4 (UT4) of the Very Large Telescope (VLT); they mark the first use of multiple lasers at ESO and they are the most powerful laser guide stars ever used in astronomy. Some 90 kilometres up in the atmosphere, the lasers excite atoms of sodium, creating artificial stars for the telescope’s adaptive optics systems.

    Modern telescopes use adaptive optics systems to compensate for the blurring effect of the Earth’s atmosphere. To do this, the telescope needs to be able to see a bright reference star while it is observing its main target. However, there is not always a suitably bright star nearby, so astronomers use lasers to create artificial stars exactly where they need them. Sodium atoms high in the atmosphere are made to glow by the action of the lasers, forming tiny patches of light that mimic real stars.

    Using multiple lasers simultaneously allows the atmosphere’s properties to be better characterised — resulting in a much better image quality in a larger field of view where the image is corrected — than is possible with just one laser. The four lasers just fitted to UT4 serve one of the most sophisticated laser guide star systems ever built and are an example of how ESO enables European industry to lead complex research and development projects. The new lasers will permit the VLT to produce very sharp images, almost at the diffraction limit of the telescope. With this new facility, the Paranal Observatory continues to have the most advanced and the largest number of adaptive optics systems in operation today. This new system will also pave the way for a similar system on ESO’s forthcoming European Extremely Large Telescope, the world’s biggest eye on the sky. Credit: ESO/F. Kamphues

    The lasers are only installed on Unit Telescope 4, also known as Yepun, as part of a recently-completed project to turn Yepun into a fully adaptive telescope. The new Adaptive Optics Facility (AOF) saw first light earlier in the year, and we chatted with Robin Arsenault (AOF Project Manager) and Harald Kuntschner (AOF Project Scientist) to find out the story behind this cutting-edge facility.

    Q: So let’s start off with the basics. Why do we need the Adaptive Optics Facility?

    Robin Arsenault (RA): A major problem in ground-based astronomy is the atmosphere. In bad seeing conditions, the light from stars and galaxies becomes distorted as it passes through our atmosphere and this affects the quality of the images we obtain.

    Harald Kuntschner (HK): Seeing is an astronomical term that is a measure of how much the atmosphere moves. Bad seeing results in smeared out images. For example, two close stars might appear as one. Seeing can change a lot every half an hour — even every minute — and to get a better image, you either have to get very lucky on a clear night, which might take years to randomly achieve, or you can improve the conditions artificially and vastly boost the chances of taking good data.

    4
    4 Lasers on Yepun schematic

    RA: The AOF is our solution to this. It’s an adaptive optics system designed to correct for this blurring effect of the Earth’s atmosphere in real-time, allowing us to see astronomical objects in much finer detail. It has several fundamental components, including the four 22-watt lasers, which create artificial guide stars in the upper atmosphere by stimulating sodium atoms there. The adaptive optics system uses these stars to determine the turbulence of the atmosphere — to create a kind of map — and calculates corrections a thousand times per second, which make the thin secondary mirror constantly change its shape to correct for the distorted light. Finally, the corrected light is directed into an instrument to actually take the scientific observations.

    HK: For the first scientific light of the system, we used the powerful MUSE instrument and produced some really fantastic images of globular clusters, planetary nebulae, and more.

    Q: Why is the AOF so exciting? How will it benefit the science done by the VLT?

    RA: The end result of the system is a much sharper image than what we could have obtained without adaptive optics — it reveals much finer details and very faint objects. The AOF system is essentially equivalent to raising the VLT about 900 metres higher in the air, above the most turbulent layer of atmosphere. In the past, if we wanted sharper images, we would have had to find a better site or use a space telescope — but now with the AOF, we can create much better conditions right where we are, for a fraction of the cost!

    4
    The planetary nebula NGC 6369 seen with natural seeing (left) and when the AOF is providing ground layer correction of the turbulent atmosphere (right). The AOF provides much sharper view of celestial objects and enables access to much finer and fainter structures.
    Credit: ESO/P. Weilbacher (AIP)

    HK: Right now, comparison images only look like a small improvement over natural seeing conditions, but for astronomers this is fantastic and will pay off even more in the near future. One amazing thing is that the AOF can also work over long time periods, for several hours, which is key to taking excellent long exposure data — such as with MUSE, which, although a huge step up in efficiency, requires up to fifty hours of data for a deep field.

    Q: What were the biggest challenges you faced when building the AOF?

    HK: The first challenge in my mind was building the very large deformable secondary mirror (DSM) with the many actuators, which began before I joined the project in 2009/10. Making what’s essentially a movable 2mm-thick shell of glass 1 metre in diametre hanging above the main mirror was a bold choice, but it has delivered on its promises. The handling procedures of the shell and the DSM have taken place so many times now in both Garching and Paranal — without incident! — that despite the mirror’s fragility, I’m confident it is in safe hands.

    4
    A second shell mirror of remarkable quality has been delivered to ESO by Safran–Reosc. This is an improved version of an earlier shell mirror delivered in late 2011. Both mirrors are a mere 2 millimetres thin but 1.12 metres in diameter, and will be crucial for the upgrade of Unit Telescope 4 of ESO’s Very Large Telescope (VLT) to a fully adaptive system. A thin shell mirror is deformed several thousand times per second to compensate for turbulence in the Earth’s atmosphere. The result is a much sharper image, allowing astronomers to study the Universe in greater detail than possible before. Credit: ESO

    RA: I definitely agree that the deformable mirror was a major challenge. At the time we started the project, the secondary mirror we had in mind was a big step up from previous units, but it seemed like an excellent stepping stone for even larger secondary mirrors — such as for the Extremely Large Telescope. During the test phase of the mirror for the AOF, we did experience a couple of serious failures. We didn’t plan these, but we knew they were more likely to happen early on, and thus it validated our strategy to have a long and thorough test period in Garching so we had a chance to resolve them. Such failures on the telescope would have been so much more complicated to resolve and would have caused much unwanted telescope downtime.

    Another challenge was building the lasers for the 4 Laser Guide Star Facility. After early technological difficulties, we made the decision to outsource the laser procurement — a courageous and somewhat unpopular decision, but in the end it paid off. Once we had found a suitable company, Toptica, it went rather straightforwardly, but the period of 2007 to 2009 was highly tense as a failure to find a laser supplier could have brought the AOF project to a stop!

    Q: What is the most exciting aspect of your involvement in the project?

    HK: For me as astronomical support, it was helping to bring the project to a successful end by knowing a lot of technical details while keeping the science opportunities in close sight. We started this with MUSE, providing a correction for the ground layer of the atmosphere over a wide field of view, and saw excellent results in commissioning. I expect to see this continued with HAWK-I and the next step for MUSE: a narrow-field mode that will correct for turbulence at any altitude.

    RA: I feel truly grateful to have had the opportunity to work with so many people at ESO on this project. I kept being amazed at their motivation and drive to accomplish their tasks for the AOF. It has been such a long project — over ten years — and they all did their part within their capabilities, and all had a different way of tackling it. Some were more efficient, some better documented their work, some were more practical… but in the end all the deliverables were up to specifications and each engineer and technician was behind their work 100%, supporting the AOF all the way to the telescope commissioning.

    6
    This stunning image of the planetary nebula NGC 6563 was obtained with the powerful symbiosis between the AOF and MUSE, revealing the faint nebula structures as never seen before. Left: without adaptive optics. Right: with the AOF.
    Credit: ESO/P. Weilbacher (AIP)

    Q: What are you personally looking forward to the most when using the AOF?

    HK: Personally, I’m keen to see objects that have previously been imaged by MUSE in much better spatial resolution.

    ESO MUSE on the VLT

    I’m interested in looking into the centres of galaxies and studying how their cores work, and to take much sharper images of objects within galaxies, such as globular clusters. This system essentially enables my research — I couldn’t do it without the AOF.

    RA: I won’t be using the AOF for science myself, but my concern is to keep these high-tech systems performing well and making sure the staff at Paranal have been given the tools to maintain them and operate them at maximum efficiency. To summarise, I’m looking forward to an efficient operation of the AOF with well-tuned systems!

    Q: One last question — what’s the future of adaptive optics technology, at ESO and worldwide?

    HK: ESO is driving the development of these systems. In particular, we’re showing the applications with instruments to see how the science improves, demonstrating the excellent results that can be achieved. In the future, the AOF will be used with instruments other than MUSE, including HAWK-I, which is a near-infrared imager. Later on we’ll also use the AOF with the upcoming instrument ERIS [no image available.

    ESO HAWK-I the ESO Very Large Telescope at the Paranal Observatory in Chile, with an elevation of 2,635 metres (8,645 ft) above sea level

    RA: The AOF is really also a pathfinder for the Extremely Large Telescope. Of course, they’re different facilities, but we’ve learned an incredible number of things from building the AOF that will be helpful for the ELT — how to fine-tune an adaptive optics system, how to operate it, how to precisely understand the problems and how to improve the efficiency… All of these things were fundamental learning curves that will help us with the ELT. And it’s not only the scientists and engineers who have benefited — our industry partners have also gained invaluable experience and expertise, which they can use to overcome the challenges of building the ELT.

    See the full article here .

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    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”.

    ESO LaSilla
    ESO/Cerro LaSilla 600 km north of Santiago de Chile at an altitude of 2400 metres.

    ESO VLT
    VLT at Cerro Paranal, with an elevation of 2,635 metres (8,645 ft) above sea level.

    ESO Vista Telescope
    ESO/Vista Telescope at Cerro Paranal, with an elevation of 2,635 metres (8,645 ft) above sea level.

    ESO NTT
    ESO/NTT at Cerro LaSilla 600 km north of Santiago de Chile at an altitude of 2400 metres.

    ESO VLT Survey telescope
    VLT Survey Telescope at Cerro Paranal with an elevation of 2,635 metres (8,645 ft) above sea level.

    ALMA Array
    ALMA on the Chajnantor plateau at 5,000 metres.

    ESO E-ELT
    ESO/E-ELT to be built at Cerro Armazones at 3,060 m.

    ESO APEX
    APEX Atacama Pathfinder 5,100 meters above sea level, at the Llano de Chajnantor Observatory in the Atacama desert.

    Leiden MASCARA instrument, La Silla, located in the southern Atacama Desert 600 kilometres (370 mi) north of Santiago de Chile at an altitude of 2,400 metres (7,900 ft)

    Leiden MASCARA cabinet at ESO Cerro la Silla located in the southern Atacama Desert 600 kilometres (370 mi) north of Santiago de Chile at an altitude of 2,400 metres (7,900 ft)

    ESO Next Generation Transit Survey at Cerro Paranel, 2,635 metres (8,645 ft) above sea level

    SPECULOOS four 1m-diameter robotic telescopes 2016 in the ESO Paranal Observatory, 2,635 metres (8,645 ft) above sea level

    ESO TAROT telescope at Paranal, 2,635 metres (8,645 ft) above sea level

     
  • richardmitnick 9:19 am on August 2, 2017 Permalink | Reply
    Tags: AOF- Adaptive Optics Facility, , , , , Cutting-edge Adaptive Optics Facility Sees First Light, ,   

    From ESO: “Cutting-edge Adaptive Optics Facility Sees First Light” 

    ESO 50 Large

    European Southern Observatory

    2 August 2017
    Harald Kuntschner
    ESO, AOF Project Scientist
    Garching bei München, Germany
    Tel: +49 89 3200 6465
    Email: hkuntsch@eso.org

    Richard Hook
    ESO Public Information Officer
    Garching bei München, Germany
    Tel: +49 89 3200 6655
    Cell: +49 151 1537 3591
    Email: rhook@eso.org

    Joël Vernet
    ESO MUSE and GALACSI Project Scientist
    Garching bei München, Germany
    Tel: +49 89 3200 6579
    Email: jvernet@eso.org

    1
    The Unit Telescope 4 (Yepun) of ESO’s Very Large Telescope (VLT) has now been transformed into a fully adaptive telescope. After more than a decade of planning, construction and testing, the new Adaptive Optics Facility (AOF) has seen first light with the instrument MUSE, capturing amazingly sharp views of planetary nebulae and galaxies. The coupling of the AOF and MUSE forms one of the most advanced and powerful technological systems ever built for ground-based astronomy.

    ESO MUSE on the VLT

    2
    The planetary nebula NGC 6369 seen with natural seeing (left) and when the AOF is providing ground layer correction of the turbulent atmosphere (right). The AOF provides much sharper view of celestial objects and enables access to much finer and fainter structures. Credit: ESO/P. Weilbacher.

    The Adaptive Optics Facility (AOF) is a long-term project on ESO’s Very Large Telescope (VLT) to provide an adaptive optics system for the instruments on Unit Telescope 4 (UT4), the first of which is MUSE (the Multi Unit Spectroscopic Explorer) [1]. Adaptive optics works to compensate for the blurring effect of the Earth’s atmosphere, enabling MUSE to obtain much sharper images and resulting in twice the contrast previously achievable. MUSE can now study even fainter objects in the Universe.

    4
    The Adaptive Optics Facility works to remove the blurring effect of Earth’s atmosphere. When used one can see much finer details in the faint planetary nebula NGC 6563 as compared to the natural sky quality. Credit: ESO.

    “Now, even when the weather conditions are not perfect, astronomers can still get superb image quality thanks to the AOF,” explains Harald Kuntschner, AOF Project Scientist at ESO.

    Following a battery of tests on the new system, the team of astronomers and engineers were rewarded with a series of spectacular images. Astronomers were able to observe the planetary nebulae IC 4406, located in the constellation Lupus (The Wolf), and NGC 6369, located in the constellation Ophiuchus (The Serpent Bearer). The MUSE observations using the AOF showed dramatic improvements in the sharpness of the images, revealing never before seen shell structures in IC 4406 [2].

    5
    The AOF + MUSE at work. Inside the UT4 of the Very Large Telescope, part of the Adaptive Optics Facility, the four Laser Guide Stars Facility, point to the skies during the first observations using the MUSE instrument. The sharpness and dynamic range of images using the AOF equipped MUSE instrument will dramatically improve future observations. Credit: Roland Bacon.

    The AOF, which made these observations possible, is composed of many parts working together. They include the Four Laser Guide Star Facility (4LGSF) and the very thin deformable secondary mirror of UT4 [3] [4]. The 4LGSF shines four 22-watt laser beams into the sky to make sodium atoms in the upper atmosphere glow, producing spots of light on the sky that mimic stars. Sensors in the adaptive optics module GALACSI (Ground Atmospheric Layer Adaptive Corrector for Spectroscopic Imaging) use these artificial guide stars to determine the atmospheric conditions.

    GALACSI Adaptive Optics System for VLT

    6
    Inside the UT4 of the Very Large Telescope, part of the Adaptive Optics Facility, the four Laser Guide Stars Facility, point to the skies during the first observations using the MUSE instrument. The AOF system is composed of many parts working together to create sharp images of astronomical objects. Credit: Roland Bacon.

    One thousand times per second, the AOF system calculates the correction that must be applied to change the shape of the telescope’s deformable secondary mirror to compensate for atmospheric disturbances. In particular, GALACSI corrects for the turbulence in the layer of atmosphere up to one kilometre above the telescope. Depending on the conditions, atmospheric turbulence can vary with altitude, but studies have shown that the majority of atmospheric disturbance occurs in this “ground layer” of the atmosphere.

    “The AOF system is essentially equivalent to raising the VLT about 900 metres higher in the air, above the most turbulent layer of atmosphere,” explains Robin Arsenault, AOF Project Manager. “In the past, if we wanted sharper images, we would have had to find a better site or use a space telescope — but now with the AOF, we can create much better conditions right where we are, for a fraction of the cost!”

    7
    UT4 and the AOF at work. The four Laser Guide Stars Facility points to the skies during the first observations using the AOF-equipped MUSE instrument. Adaptive optics assist ground-based telescopes by compensating for the blurring effect of the Earth’s atmosphere on starlight. Credit: Roland Bacon.

    The corrections applied by the AOF rapidly and continuously improve the image quality by concentrating the light to form sharper images, allowing MUSE to resolve finer details and detect fainter stars than previously possible. GALACSI currently provides a correction over a wide field of view, but this is only the first step in bringing adaptive optics to MUSE. A second mode of GALACSI is in preparation and is expected to see first light early 2018. This narrow-field mode will correct for turbulence at any altitude, allowing observations of smaller fields of view to be made with even higher resolution.

    “Sixteen years ago, when we proposed building the revolutionary MUSE instrument, our vision was to couple it with another very advanced system, the AOF,” says Roland Bacon, project lead for MUSE. “The discovery potential of MUSE, already large, is now enhanced still further. Our dream is becoming true.”

    One of the main science goals of the system is to observe faint objects in the distant Universe with the best possible image quality, which will require exposures of many hours. Joël Vernet, ESO MUSE and GALACSI Project Scientist, comments: “In particular, we are interested in observing the smallest, faintest galaxies at the largest distances. These are galaxies in the making — still in their infancy — and are key to understanding how galaxies form.”

    Furthermore, MUSE is not the only instrument that will benefit from the AOF. In the near future, another adaptive optics system called GRAAL will come online with the existing infrared instrument HAWK-I, sharpening its view of the Universe. That will be followed later by the powerful new instrument ERIS.

    ESO Graal

    ESO HAWK-I the ESO Very Large Telescope at the Paranal Observatory in Chile, with an elevation of 2,635 metres (8,645 ft) above sea level

    ESO is driving the development of these adaptive optics systems, and the AOF is also a pathfinder for ESO’s Extremely Large Telescope,” adds Arsenault. “Working on the AOF has equipped us — scientists, engineers and industry alike — with invaluable experience and expertise that we will now use to overcome the challenges of building the ELT.”
    Notes

    [1] MUSE is an integral-field spectrograph, a powerful instrument that produces a 3D data set of a target object, where each pixel of the image corresponds to a spectrum of the light from the object. This essentially means that the instrument creates thousands of images of the object at the same time, each at a different wavelength of light, capturing a wealth of information.

    [2] IC 4406 has previously been observed with the VLT (eso9827a).

    [3] At just over one metre in diameter, this is the largest adaptive optics mirror ever produced and demanded cutting-edge technology. It was mounted on UT4 in 2016 (ann16078) to replace the telescope’s original conventional secondary mirror.

    [4] Other tools to optimise the operation of the AOF have been developed and are now operational. These include an extension of the Astronomical Site Monitor software that monitors the atmosphere to determine the altitude at which the turbulence is occurring, and the Laser Traffic Control System (LTCS) that prevents other telescopes looking into the laser beams or at the artificial stars themselves and potentially affecting their observations.

    7
    ESO 338-4 is a starburst galaxy located in Sagittarius, the Archer. It is currently in the process of merging, with several smaller galaxies colliding to form the final galaxy. The new AOF+MUSE data clearly resolve several bright knots where intense star formation, induced by the merging, is occurring, as well as filaments of glowing hydrogen gas. Credit: ESO/P. Weilbacher.

    See the full article here .

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    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”.

    ESO LaSilla
    ESO/Cerro LaSilla 600 km north of Santiago de Chile at an altitude of 2400 metres.

    ESO VLT
    VLT at Cerro Paranal, with an elevation of 2,635 metres (8,645 ft) above sea level.

    ESO Vista Telescope
    ESO/Vista Telescope at Cerro Paranal, with an elevation of 2,635 metres (8,645 ft) above sea level.

    ESO NTT
    ESO/NTT at Cerro LaSilla 600 km north of Santiago de Chile at an altitude of 2400 metres.

    ESO VLT Survey telescope
    VLT Survey Telescope at Cerro Paranal with an elevation of 2,635 metres (8,645 ft) above sea level.

    ALMA Array
    ALMA on the Chajnantor plateau at 5,000 metres.

    ESO E-ELT
    ESO/E-ELT to be built at Cerro Armazones at 3,060 m.

    ESO APEX
    APEX Atacama Pathfinder 5,100 meters above sea level, at the Llano de Chajnantor Observatory in the Atacama desert.

    Leiden MASCARA instrument, La Silla, located in the southern Atacama Desert 600 kilometres (370 mi) north of Santiago de Chile at an altitude of 2,400 metres (7,900 ft)

    Leiden MASCARA cabinet at ESO Cerro la Silla located in the southern Atacama Desert 600 kilometres (370 mi) north of Santiago de Chile at an altitude of 2,400 metres (7,900 ft)

     
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