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  • richardmitnick 12:26 pm on August 9, 2019 Permalink | Reply
    Tags: , ESOblog, Ivo Saviane - Site Manager since 2013.   

    From ESOblog: “A string of domes in the desert” 

    ESO 50 Large

    From ESOblog

    1
    9 August 2019 People@ESO

    La Silla became ESO’s first observatory when it opened in 1969. Since then, the majestic gathering of telescopes in the Chilean desert has led to an enormous number of scientific discoveries, with on average 300 refereed publications attributed to La Silla telescopes every year. To mark the 50th anniversary of the observatory, we find out what it takes to run such an impressive place from Ivo Saviane, who has been Site Manager since 2013.

    1
    Ivo Saviane

    Q. Could you begin by telling us what you love or what inspires you about La Silla?

    A. The very existence of La Silla as a string of domes in the middle of the Atacama Desert is just incredible, but I also wonder at the extraordinary science that has been (and is still being!) carried out here. For example, two La Silla telescopes were used to find the most remote gamma-ray burst, the observatory played a key role in the Deep Impact campaign, the ESO 3.6-metre telescope was used to find potentially-habitable exoplanet Proxima b, and the TRAPPIST-south telescope was used to detect planets around TRAPPIST 1.

    And because La Silla hosts telescopes and instruments spanning five decades, there is a huge amount of history here. This allows me to set more recent ESO achievements in good evolutionary perspective.

    Q. So what does a typical day in your life as La Silla Site Manager look like?

    A. My main role is to be the hub of an incessant information flow, which happens mostly by email, but also through meetings and daily encounters with staff — for example coffee breaks are a valuable way to keep an eye on observatory life! Input is received through these channels, and most of the time follow-up actions are triggered.

    Many actions are recurring and plannable but others are a consequence of the complex dynamic nature of an observatory: safety concerns arise, the weather can get nasty, people become sick, visitors might be delayed or not arrive, instruments and telescopes can suffer a myriad of technical hiccups, transportation vehicles can break down, staff leave and must be replaced, training activities must be organised, hardware is imported and exported, requests are received to install new facilities on site, etc.

    Some of these issues can be solved internally but often help is required from across ESO. In addition, some actions must be coordinated with other observatories, for example fighting light pollution, maintaining access roads, and exchanging instrumentation. This means it’s vital to maintain good relationships with competing facilities in Chile.

    My typical day thus consists of processing emails, holding internal meetings, contacting other partners, and deciding on actions to be carried out. These might not sound like the most interesting tasks, but they are vital for La Silla to continue to be such a productive observatory.

    Q. This year is the 50th anniversary of the inauguration of La Silla. How has La Silla changed over the time that you have known it?

    A. My first time at La Silla was in 1993, when I arrived at the New Technology Telescope (NTT) for an observing run. This was only four years after its inauguration as “The Best Telescope Yet”, as Sky & Telescope put it on the cover of their September 1989 issue. The NTT marked the peak of La Silla’s golden age, but in 1987 the ESO Council had already decided to build the Very Large Telescope (VLT), likely on the Paranal mountain. It was then natural that focus and resources would move away from La Silla, so the observatory went through a series of reductions in scope.

    ____________________________________________
    An observatory with no resident astronomers is something rather unusual, and at that time the change sparked some outrage in the astronomical community.
    ____________________________________________

    But since then, the biggest change I witnessed was in 2009, when the La Silla 2010+ scheme was inaugurated: among a number of changes, the decision was made not to have support astronomers on site to help visitors during their observing runs or carry out observations in so-called “service mode”. An observatory with no resident astronomers is something rather unusual, and at that time the change sparked some outrage in the astronomical community. However, over time people have become accustomed to it and complaints about missing scientific support are very rare these days.

    The drastic reduction in staff after 2009 means that now only a few people inhabit an urbanised site meant for a much larger population. This might conjure up scenes from a science fiction film, but the remaining staff must have continuous direct interaction with each other in order to keep the place running, so team spirit has strengthened. Besides, with so few people, everyone’s had to develop skills beyond their original experience, which can make daily work more interesting.

    One might also remark that astronomy has moved away from the kind of individual or small group efforts that dominated during most of the last century. An ever-growing mass of data, and the need to gather them over the whole spectral range and resolution, has triggered a trend where it is now more likely that high-impact papers are the results of large collaborations. In this context it is good to see a steady flow of young and enthusiastic researchers populating the La Silla control room every night.

    ____________________________________________
    I personally think that La Silla’s smaller telescopes could survive only by joining forces and eventually establishing a worldwide network.
    ____________________________________________

    The future of La Silla depends on the will of ESO and its community to keep operating the observatory’s two main telescopes; the NTT and the ESO 3.6-metre. In the upcoming age of 10-metre and 40-metre optical-infrared telescopes I personally think that La Silla’s smaller telescopes could survive only by joining forces and eventually establishing a worldwide network. But at the moment we are expecting two new instruments — SOXS for the NTT and NIRPS for the ESO 3.6-metre telescope — and several new hosted projects are about to start operations. Therefore I expect that the nature of La Silla will not change much in the next decade or so.

    ____________________________________________
    If I had to pick some highlights, the changing natural environment would be at the top.
    ____________________________________________

    Q. What are your most special memories from your time at La Silla so far?

    A. La Silla is such a unique place that all time spent there is somehow special. I think it is no coincidence that, given the choice, most visiting artists in the past selected to stay at La Silla over other ESO sites.

    But if I had to pick some highlights, the changing natural environment would be at the top: the extraordinary view of the flowering desert, when hills turn green and great swaths of magenta flowers appear; the green flash before the sun disappears below a razor-sharp horizon; snow covering the landscape; shadows of clouds on brightly coloured mountains; the occasional rain that fills the air with its scent; herds of guanacos browsing the bushes; majestic condors circling the dome of the 3.6-metre telescope; desert foxes watching you from a distance.

    And over all this sweeps the magnificent night sky. On my first observing run, I had fallen asleep whilst been driven up to the summit after an exhausting journey. As I opened the door of the vehicle and looked up, I almost fell back in awe at the view of the Milky Way shining overhead. I felt overwhelmed by the grandiosity of the sight, but at the same time the urge to understand what was happening in front of my eyes was spurred beyond resistance. It seems impossible that somebody could look at the night sky at La Silla and not have the same feeling!

    ____________________________________________
    I almost fell back in awe at the view of the Milky Way shining overhead.

    3
    A swath of stars appears to cut the New Technology Telescope in two. The majestic telescope enclosure aligns perfectly with the Milky Way’s central region.
    Credit: ESO/B. Tafreshi (twanight.org)
    ____________________________________________

    But back to Earth, it takes some special characters to adapt to such an unusual lifestyle, where you work and live with the same people in a confined place for several days in a row. Thus inevitably, memorable conversations and stories come alive, so some of my best memories are related to these aspects of the social life at La Silla. In particular I remember fondly the midnight meals shared with visiting and support astronomers from all around the world. The dimly lit dining room helped create a feeling of sharing and good spirit, and life experiences were shared from different cultural backgrounds, enriching everybody’s souls.

    Q. La Silla is home to a large (and growing!) number of telescopes. Do you have a favourite?

    A. In the past, I spent many nights as an observer or support astronomer working with the NTT, so that is high on my list. However my dearest memory rests with the MPG/ESO 2.2-metre telescope: in September 1996 I was there observing a dwarf galaxy in the constellation of Phoenix, and I was hoping that the new EFOSC2 detector, with its better response in the blue part of the spectrum, would allow me to resolve a special class of stars that are key to inferring the age of a stellar population. At that time we were still observing in control rooms inside each telescope building, so I launched very long exposures and went out to look at the sky.

    I could see the open dome slit and the top ring of the telescope pointing towards “my” galaxy, as it slowly tracked the motion of the stars, making a subtle hum, which was interrupted every few minutes by a metallic sound coming from the dome as it changed position. These visual and acoustic impressions seemed to announce that the secrets of the galaxy would soon be revealed to me, and I felt almost at one with the instrument and the night sky. You can imagine my excitement when I could see those stars in the data, which sealed that September night into my memory.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Visit ESO in Social Media-

    Facebook

    Twitter

    YouTube

    ESO Bloc Icon

    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 VLT at Cerro Paranal in the Atacama Desert, •ANTU (UT1; The Sun ),
    •KUEYEN (UT2; The Moon ),
    •MELIPAL (UT3; The Southern Cross ), and
    •YEPUN (UT4; Venus – as evening star).
    elevation 2,635 m (8,645 ft) from above Credit J.L. Dauvergne & G. Hüdepohl atacama photo,

    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, a major asset of the Adaptive Optics system


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

    ESO VLT 4 lasers on Yepun


    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.

    ESO/NRAO/NAOJ ALMA Array in Chile in the Atacama at Chajnantor plateau, at 5,000 metres

    ESO/E-ELT,to be on top of Cerro Armazones in the Atacama Desert of northern Chile. located at the summit of the mountain at an altitude of 3,060 metres (10,040 ft).


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

     
  • richardmitnick 1:07 pm on July 12, 2019 Permalink | Reply
    Tags: "The mystery of the darkening sky", , , , , ESOblog, Solar Eclipses through history   

    From ESOblog: “The mystery of the darkening sky” 

    ESO 50 Large

    From ESOblog

    12 July 2019
    On the Ground

    2

    On 2 July 2019, a solar eclipse passed over part of South America, temporarily bringing an eerie darkness to ESO’s La Silla Observatory in Chile. It was a once-in-a-lifetime opportunity for many to view an eclipse from a unique spot. But eclipses were not always viewed as the wondrous spectacles that they are today. They were once bad omens, foreshadowing terrible events and instilling fear in those who saw them.

    3
    The path of the 2019 solar eclipse. Observers within the central red line saw a total solar eclipse, whilst those further from the path of totality saw a partial solar eclipse. Credit: OpenStreetMap contributors, timeanddate.com

    Just about 2000 years ago humans came to understand that a solar eclipse occurs when the orbit of the Moon causes it to pass exactly between the imaginary line connecting Earth and the Sun. When this happens the Moon blocks the light from the Sun, casting a shadow onto the Earth, which moves across Earth’s surface as it rotates.

    Solar eclipse expert and ESO photo ambassador Petr Horálek explains, “A total eclipse happens because although the Sun is about 400 times further from the Earth than the Moon, its diameter is 400 times larger. This means they appear the same size in the sky so the Sun is almost perfectly blocked by the Moon. The really amazing thing about this is that a total solar eclipse gives us the chance to see the Sun’s corona — the outer layer of its impressive atmosphere. And if that wasn’t enough, there are many breathtaking phenomena to be seen in the moments before and after the Moon completely blocks the Sun”.

    The recent solar eclipse at La Silla Observatory lasted more than two hours, with the Sun being completely covered by the Moon for almost two minutes. Over 1000 visitors travelled to La Silla from around the world hoping to get a glimpse of the spectacle. Skies were clear, giving astronomers the opportunity to use the observatory’s world-class telescopes to observe the eclipse for outreach and science purposes, following a long tradition of taking advantage of eclipses for scientific research.

    4
    Composed of several images taken during the total solar eclipse at La Silla, this image highlights Bailey´s Beads, a feature visible only at the very beginning and the very end of totality. Baily´s Beads are caused by the Moon´s mountains, valleys, and craters creating an uneven edge of the Moon, where small “beads” of sunlight still shine through the lowest parts for a few moments after the rest of the Sun is covered.
    Credit: ESO/P. Horálek

    65
    An image of the Sun during the total solar eclipse visible from ESO’s La Silla Observatory on 2 July 2019 at the moment when most of its face is occulted by the moon. The eclipse lasted roughly two and a half hours, with almost two minutes of totality, and was visible across a narrow band of Chile and Argentina. To celebrate this rare event ESO invited 1000 people, including dignitaries, school children, the media, researchers, and the general public, to come to the Observatory to watch the eclipse from this unique location. Credit: ESO/M. Zamani

    The recent eclipse inspired awe and wonder in all who were lucky enough to see it, but before the phenomenon was well-understood, eclipses were mysterious and often terrifying events. “People are scared of what they don’t understand, and what could be more confusing and frightful than suddenly being shrouded in darkness,” Petr says.


    A video of the total solar eclipse visible from La Silla Observatory on 2 July 2019. Credit: ESO/R. Lucchesi

    6
    Babylonian Solar Eclipse Tablet listing eclipses between 518 and 465 BCE. Credit: NASA

    The earliest eclipses were documented on clay tablets and cave walls, with the very first written record coming from China in 2137 BCE. According to traditional astrological theories, the Sun was the symbol of the Chinese Emperor and so eclipses in China stood as imperial warnings.

    Petr explains further: “In Chinese culture it was believed that eclipses were caused by a hungry dragon devouring the Sun. The record from 2137 BCE describes two royal astronomers, Chi and Ho, who had not warned others about the eclipse and were too drunk to fulfil their task of beating a drum to scare away the dragon”.

    It wasn’t until almost 1500 years later that the Greek philosopher Thales of Miletus accurately predicted a solar eclipse, according to ancient Greek historian Herodotus. If Herodotus’s account is to be believed, the Eclipse of Thales is the earliest recorded that had been foreseen in advance, even though eclipses were still not understood at the time. How exactly Thales predicted the eclipse remains uncertain it is possible that he knew about the periodicities of eclipses, that he was able to calculate it or that he just made a lucky guess! Horálek explains: “Nowadays it is easy to predict future solar eclipses. They follow a strict periodicity and can be predicted with mathematical calculations that consider the position of the Moon in relation to the Sun. Astronomers can do it for thousands of years into the future!”.

    Running these calculations in reverse, many historians believe that the Eclipse of Thales was the solar eclipse of 28 May, 585 BCE. Interpreted by Herodotus as an omen, it interrupted a battle in a long-standing war between the Medes and the Lydians. The fighting stopped immediately, and they agreed to a truce.

    6
    The treaty of Verdun led to the Carolingian empire being split into three regions (shown here in pink, green, and yellow.
    Credit: Wikimedia commons

    Some historical eclipses are still shrouded in mystery. Reports from both Christians and non-Christians of the death of Jesus describe a period of daytime darkness. Some historians believe this could have been caused by a solar eclipse, but bewilderingly, the crucifixion supposedly took place during the Jewish festival of Passover, which is celebrated during a Full Moon. A solar eclipse can only occur during a New Moon. Furthermore, present-day astronomers believe that the only two eclipses to have occurred near the time of the crucifixion were closer to Antarctica and Australia — it seems unlikely that either was visible from Jerusalem!

    It wouldn’t be an exaggeration to say that solar eclipse events may have even changed the course of history. Louis the Pious, son of Charlemagne, was head of the Carolingian empire when he witnessed a solar eclipse on 5 May 840 CE. According to legend, it terrified him so much that he died shortly afterwards. His three sons then began to dispute his succession. After three years of debate, the quarrel was settled with the Treaty of Verdun. This treaty divided Europe into three large areas which indirectly led to present day France, Germany and Italy.

    Three hundred years later in 1133 CE, King Henry I of England died shortly after he observed a solar eclipse. William of Malmesbury wrote in the manuscript Historia Novella that the “hideous darkness” agitated the hearts of men. After the death, a struggle for the throne threw the kingdom into chaos and civil war.

    8
    The first successful photo of a solar eclipse, clearly showing the corona — the upper layer of the Sun’s atmosphere. Credit: Wikimedia commons

    Whilst historical figures were shocked by eclipses, by the seventeenth century physicists began using them to investigate the Sun scientifically. The first accurate and scientifically useful photo of an eclipse was taken in 1851 at the Royal Observatory in Königsberg. To take this photo, daguerreotypist Johann Julius Friedrich Berkowski exposed a copper plate directly to the Sun’s light through a small refracting telescope, capturing an 84-second exposure which for the first time allowed scientists to study the Sun’s corona long after totality had passed.

    Eight years later, German physicist Gustav Kirchhoff figured out how to analyse light from the Sun and the stars to deduce their chemical composition. Scientists eagerly awaited the next solar eclipse, which would allow them to study the chemistry of solar prominences. In 1868, the opportunity finally arose. French astronomer Pierre Jules César Janssen camped out in India to watch the Moon pass in front of the Sun, revealing brilliant solar prominences. Like other Sun-gazers that morning, Janssen discovered that the prominences were mostly made of hot hydrogen gas, as was expected. But he also used a spectroscope to discover something intriguing — yellow light was present that didn’t match the wavelength of any known element. Further studies led him to discover that this line was actually produced by Helium, named after “Helios”, the Greek personification of the Sun. And thus Helium was discovered on the Sun before it was discovered on Earth.

    9
    This image was taken by the ESA–CESAR team of scientists at the total solar eclipse visible from ESO’s La Silla Observatory on 2 July 2019. It was made by combining multiple polarised images of the solar corona during totality to bring out the details in its structure. Credit: ESA/CESAR

    When Albert Einstein published his general theory of relativity in 1915, he proposed three critical tests to prove it, one of which was that light should be deflected by a gravitational field. This phenomenon could be investigated by measuring whether light from distant stars is diverted by the gravity of the Sun. Just before the total solar eclipse of 1919, Sir Arthur Eddington took nighttime measurements of the positions of the Kappa Tauri double star in the Hyades cluster. During the eclipse, the Sun crossed Kappa Tauri, and the starlight became visible. Comparison of the stars’ normal positions and the corresponding positions detected during the eclipse showed that light was indeed deflected when it passed close to the Sun. Einstein’s world-changing theory was proved to be correct!

    Eddington/Einstein exibition of gravitational lensing solar eclipse of 29 May 1919

    Past eclipses have helped us make many scientific discoveries, but still today mysteries remain that astronomers hope to solve by observing the Sun during future eclipses.

    Petr tells us: “In 1869 astronomers William Harkness and Charles August Young captured spectra of the solar corona and found a mysterious new element there. Eventually people discovered that this “new element” was in fact iron that had been ionised 13 times! But this discovery brings with it a bigger mystery; such strong ionisation can only occur in places with temperatures of millions of degrees. The temperature of the corona cannot be this high, so the big question is: where and how does this ionisation occur and how do the ionised elements move to the corona? This is still the greatest coronal mystery”.

    9
    This image of the solar corona was taken by an ESA–CESAR team of scientists during the total solar eclipse visible from ESO’s La Silla Observatory on 2 July 2019. It clearly shows bright red prominences — places where loops of glowing plasma flow up from the Sun’s surface. The path of this plasma, composed of hydrogen and helium, is probably determined by the Sun’s magnetic fields, which can twist and tangle in strange ways. We know that prominences can persist for weeks or even months, but we don’t fully understand why they exist or what their internal dynamics are. This is why continuing research into the Sun’s complex atmosphere is important, much of which can only be done during total solar eclipses. Credit: ESA/CESAR

    Solar tornadoes, vortices of magnetic turbulence that swirl up from the surface, might be to blame. So too may be deeper, magnetic tsunamis within the sun, transferring their heat outward.

    “Observations during future eclipses could help settle the issue between the two, or reveal another unexpected cause,” Petr continues. “Moreover, solving this mystery and getting a better understanding of upper solar atmospheric physics could allow us to better predict space weather in the future, potentially saving a lot of money, and even lives.”

    “Watching a total solar eclipse is so amazing and unique that your breath is taken away in the first few seconds of the show. The Sun looks like it has frozen. Nature, confused by the darkness, goes to sleep, and the excitement of people is incredible. After you’ve seen it once, you can’t wait to see it again!”

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Visit ESO in Social Media-

    Facebook

    Twitter

    YouTube

    ESO Bloc Icon

    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 VLT at Cerro Paranal in the Atacama Desert, •ANTU (UT1; The Sun ),
    •KUEYEN (UT2; The Moon ),
    •MELIPAL (UT3; The Southern Cross ), and
    •YEPUN (UT4; Venus – as evening star).
    elevation 2,635 m (8,645 ft) from above Credit J.L. Dauvergne & G. Hüdepohl atacama photo,

    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, a major asset of the Adaptive Optics system

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

    ESO VLT 4 lasers on Yepun


    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.

    ESO/NRAO/NAOJ ALMA Array in Chile in the Atacama at Chajnantor plateau, at 5,000 metres

    ESO/E-ELT,to be on top of Cerro Armazones in the Atacama Desert of northern Chile. located at the summit of the mountain at an altitude of 3,060 metres (10,040 ft).


    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

    ESO Speculoos telescopes four 1m-diameter robotic telescopes at ESO Paranal Observatory 2635 metres 8645 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 1:03 pm on June 28, 2019 Permalink | Reply
    Tags: Astronomical site selection, , , , , ESOblog   

    From ESOblog: “Home sweet home” 

    ESO 50 Large

    From ESOblog

    How to decide where a telescope should spend its life.

    ESO/E-ELT,to be on top of Cerro Armazones in the Atacama Desert of northern Chile. located at the summit of the mountain at an altitude of 3,060 metres (10,040 ft).

    28 June 2019

    As soon as a new telescope gets the green light to be developed, it’s time to find it the perfect home. This is no easy task, as different environmental conditions can have a huge effect on the quality of observations a telescope can make. We speak to Marc Sarazin and Julio Navarrete of ESO’s Site Survey Team, who were involved in testing sites for both the Very Large Telescope (VLT) and the Extremely Large Telescope (ELT).

    ESO VLT at Cerro Paranal in the Atacama Desert, •ANTU (UT1; The Sun ),
    •KUEYEN (UT2; The Moon ),
    •MELIPAL (UT3; The Southern Cross ), and
    •YEPUN (UT4; Venus – as evening star).
    elevation 2,635 m (8,645 ft) from above Credit J.L. Dauvergne & G. Hüdepohl atacama photo,

    Q. Firstly, can you tell us a bit more about your role here at ESO?

    Marc Sarazin (MS): I was hired back in the eighties to help choose a site for the ambitious Very Large Telescope (VLT), and I still work in telescope site selection today! In reality this means working with other staff and local contractors to decide on the best place for a telescope to be located. We gather lots of information about a site before the final site selection committee — which is made up of astronomers representing the scientific communities within ESO’s Member States — makes a final decision about which one is best.

    Julio Navarrete (JN): And I started at ESO’s Paranal Observatory in Chile two years after Marc started at Headquarters. I worked on site testing full time until the VLT began operating, then moved to science operation with 15% of my time dedicated to site monitoring. Before I joined ESO I was working in oil exploration; I completely changed perspective, from looking down to looking up at the sky!

    Q. What would you say are the most important criteria to consider when choosing on an astronomical observing site?

    MS: There are so many aspects to consider. Some of these, like clouds, wind, and altitude, impact the science a telescope is able to carry out. We constantly monitor the turbulence in the air above the observatories, because we want the air to be as still as possible, to minimise the blurring of light from the Universe as it travels through Earth’s atmosphere. But we also need to consider other more practical factors like cultural issues, building and maintenance costs, and ease of access to the site.

    Then there’s geology. It’s easier and cheaper to build on solid rock than sand, for example, and telescopes are very sensitive to earthquakes, so an earthquake-free zone is a bonus. Low temperatures can also pose problems because they cause the lubricant oil in telescopes to freeze. And we want to avoid dusty areas because dust landing on the mirrors can damage reflective coatings. With so many factors to consider, it takes a very long time to test and select a site!

    JN: We are also careful not to disturb animal populations too much, so ecological studies are carried out by independent institutes. For instance, when choosing a site for the ELT, we discovered that some desert mice lived on the preferred site. Fortunately there weren’t too many, so we didn’t consider it too detrimental.

    The important thing to note is that it’s impossible to find a perfect location with no problems at all. We always need to weigh up the advantages and disadvantages of each site, and finally work towards a compromise.

    2

    Testing Cerro Armazones for the Very Large Telescope. Marc and Julio with Chilean observers working on meteorology and cloud spotting. It looks pretty windy; the afternoon was always blustery but the nights were much calmer.
    Credit: Marc Sarazin/ESO

    Q. Can you walk us through the process of testing a site?

    MS: We start by using satellite observations to identify many large areas that could be suitable for a site, scientifically speaking. We eliminate some for political or safety reasons, and are typically left with three or four. Then we look for specific candidate sites within each area, for example dry summits with low levels of light pollution. And nowadays, as most people do before they go on holiday, we also tend to have a look around on Google maps before visiting the sites in person.

    For example, when choosing a site for the VLT, in South America we narrowed the choice down to Argentina and Chile. Both countries have lots of summits — just beautiful! — but there is also a lot of mining, so we needed to find somewhere far from the mines to avoid vibrations and dust. We set up dedicated robotic stations at sites across both countries, which took measurements for several years before we could make a decision. For the VLT, we also tested Gamsberg in the Namib Desert and checked sky conditions at Reunion Island.

    JN: Whilst site testing for the VLT, I had to stay onsite in a caravan with just a driver and a cook for several months at a time! This was during the eighties, when we didn’t have such independent robotic equipment, so it took more human effort to make measurements at a site. I was in charge of operating the testing instrument, diagnosing and repairing failures, and cleaning the dishes after meals.

    For the VLT, it took seven years in total to select Cerro Paranal to be its future home, with about five of these involving site testing. Testing for this long ensures that we are confident about site conditions, and are sure that we are not just testing the site in a fluke year with particularly superb conditions. But Cerro Paranal is truly excellent, with very little rain or cloud cover, wonderful conditions to carry out science, and virtually no light pollution.

    Q. And more recently you were both involved in selecting a site for ESO’s Extremely Large Telescope (ELT). Was it difficult to choose a home for the world’s “largest eye on the sky”?

    MS: Even though the ELT is huge, choosing a site for it was actually no more difficult than for the VLT, because the ELT is just one single telescope whereas the VLT is made up of four large Unit Telescopes.

    4
    Testing Cerro Armazones in 2009 for the Extremely Large Telescope.
    Credit: ESO/G. Lombardi (glphoto.it)

    For the ELT we considered sites in the Canary Islands, Morocco, Argentina and Chile. One committee was set up to analyse the scientific quality of each site based on data we provided, as well as that provided by other site testing groups using the same equipment. Then another committee had the arguably more difficult job of looking into the socio-economic nature of each site, for example political issues, ease of access and cost of construction.

    JN: But before we had come to a final decision, we had a stroke of luck. The American Thirty Metre Telescope (TMT) was due to be built on top of a mountain called Cerro Armazones, very close to the VLT.

    TMT-Thirty Meter Telescope, proposed and now approved for Mauna Kea, Hawaii, USA4,207 m (13,802 ft) above sea level

    We had actually previously considered this site as a potential for the VLT. Cerro Armazones was a wonderful site and would have been an excellent location for the TMT, but in 2009 it was decided that it would make more sense to build the telescope in the US state of Hawaii. This left Cerro Armazones thoroughly tested and now wide open.

    This mountaintop outshone all the other sites we had been looking at, so ESO snapped up the opportunity and decided to build the ELT there. Not only are the weather conditions excellent, but the proximity to the VLT means that a lot of infrastructure, for example roads and a hotel, already existed that we would have otherwise had to build. ESO also already had various agreements in place with the Chilean government, so that simplified things a lot!

    Q. Do you continue to monitor a site whilst science operations are ongoing?

    MS: Yes, we continue to monitor the “astroclimate” even when the telescopes are built and operating, using an on-site meteorological station. We do this so that astronomers can capture the best possible images, to understand the performance of the instruments and to better-plan observations. For example if we monitor a site for several years, we can predict which months are better from a scientific point of view. We can plan difficult observations during those periods, and schedule maintenance during the worst months.

    And because of climate change, some parts of the world are changing faster than others. The stability of a telescope site is really important, so we do look at how conditions change over a longer period of time. We know that the Atacama Desert, for example, has been a desert for hundreds of years, but there are cycles in the clouds. When we were first monitoring the site, about 15% of nights were cloudy. As time went on, this percentage steadily increased, and now it’s steadily decreasing again. This is a cycle that lasts about 30 years.

    Q. Do you think astronomical sites will be chosen in the same way in the future, or will technological advances change the process?

    5
    At the top of Cerro Armazones, the site of the ELT. On the right is the Differential Image Motion Monitor (DIMM), used to measure the atmospheric seeing. The white and red tower to its left is the meteorological station.
    Credit: F. Char/ESO

    MS: There was already a huge difference between choosing a site for the VLT and choosing one for the ELT. For the VLT we were using paper satellite photographs to study cloud cover, whereas for the ELT we had big databases based on meteorological models. We now have meteorological data with a resolution of just a couple of kilometres, compared to 40 kilometres in the eighties.

    We also now have information about the historical weather at a site, meaning that we don’t need to spend months or years checking the weather conditions. We do, of course, still need to investigate geology, whether we would be disturbing animal populations, and more practical issues like how easy it will actually be to build a telescope there.

    JN: But overall, now we spend a lot more time monitoring sites remotely from our offices than actually staying on the site itself. This is sad for me, because my favourite part of my job is to be out in the field, even if that means being the designated washer-upper!

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Visit ESO in Social Media-

    Facebook

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    ESO Bloc Icon

    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 VLT at Cerro Paranal in the Atacama Desert, •ANTU (UT1; The Sun ),
    •KUEYEN (UT2; The Moon ),
    •MELIPAL (UT3; The Southern Cross ), and
    •YEPUN (UT4; Venus – as evening star).
    elevation 2,635 m (8,645 ft) from above Credit J.L. Dauvergne & G. Hüdepohl atacama photo,


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

    ESO VLT 4 lasers on Yepun


    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.

    ESO/NRAO/NAOJ ALMA Array in Chile in the Atacama at Chajnantor plateau, at 5,000 metres

    ESO/E-ELT,to be on top of Cerro Armazones in the Atacama Desert of northern Chile. located at the summit of the mountain at an altitude of 3,060 metres (10,040 ft).


    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

    ESO Speculoos telescopes four 1m-diameter robotic telescopes at ESO Paranal Observatory 2635 metres 8645 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 1:13 pm on June 14, 2019 Permalink | Reply
    Tags: "Spot-on Science", , , , , , ESOblog, Paola Amico-Science Liaison   

    From ESOblog: “Spot-on Science” 

    ESO 50 Large

    From ESOblog

    Why all ESO Supernova content is checked by an active scientist.

    1
    The very first panel of the exhibition The Living Universe in the ESO Supernova Planetarium & Visitor Centre, explains why we study the Universe. From here, visitors will be taken on a journey all the way across the Universe, learning about stars, galaxies, black holes, exoplanets and much more. Credit:ESO/P. Horálek

    The ESO Supernova is the gateway to space for the European public. It provides an immersive experience that leaves visitors in awe of the Universe in which they live and seemingly-abstract concepts are explained in an innovative and engaging way. But all this is futile if we don’t get the science right. We speak to ESO scientist Paola Amico about her involvement as a “Science Liaison” for the ESO Supernova.

    2
    Paola Amico

    Q. Firstly, could you tell us what being a Science Liaison for the ESO Supernova involves?

    A. I check everything that is produced for scientific accuracy to make sure that people are as well informed as possible and that misconceptions are not spread. This all started in 2016, when there was a call for volunteers for the ESO Supernova, which was due to be opened to the public two years later.

    I applied and Tania — the Supernova Coordinator — realised I had a background in astronomy. She checked my CV to review my experience and quickly asked me to take on the role of Science Liaison! I happily accepted and continue to do this even now. It means that I evaluate the text on everything that is produced in the Supernova; this includes exhibition panels, student workshops, planetarium shows, and even the AstroCalendar, which is a kind of database of astronomical events. At the same time, I also took on the role of Science Liaison for ESO’s Department of Communications more generally.

    Q: What experience do you have that makes you a good Science Liaison?

    A: By background I am an astronomer specialising in galactic dynamics — so how galaxies rotate, dark matter and things like that. After finishing a PhD in astronomy, I started at ESO as a Fellow in 1994, and somehow I got more and more attracted to the technology that is applied to astronomy. In particular I became fascinated by detectors, which are a bit like the eyes of any telescope.

    I was later offered a fellowship in ESO’s instrumentation division, and from that moment on I managed to stay in the field of technology for astronomy. I worked as an instrument scientist and support astronomer for eight years, both at Keck Observatory and at ESO’s Paranal Observatory. My instruments were almost all capable of adaptive optics, which corrects for turbulence in Earth’s atmosphere that causes stars to twinkle and blur. Telescopes that use adaptive optics are really cool, and I think even more fun than other telescopes! Somehow it requires some real-time thinking, interacting and interpretation, because the atmosphere changes all the time, making it quite human-like. I would say working on instruments with adaptive optics is now my role of expertise, I am a systems engineer and I support two instruments on ESO’s Extremely Large Telescope.

    I’m very lucky, because I’m pretty old (ha!) and saw many astronomical technologies being born. The application of technology to astronomy was really starting to take off when I began working in the field. With detectors, for example, they were first one pixel, then eight, and now we are working with detectors made up of millions of pixels! It’s been a real privilege to see that happen and I think working in astronomy during this time of change has given me vital knowledge that I can apply to my Science Liaison role.

    As well as explaining current science and astronomy, the ESO Supernova also presents ESO and all the incredible telescopes that we operate. For example, I was involved in developing a workshop all about optics that shows students and teachers how instruments work and what people can do even with small telescopes. I think my experience in astronomy technology really gives me a broad range of knowledge in the “what”, “why” and “how” of astronomy that makes me a good fit for the Science Liaison role.

    Q: The ESO Supernova covers pretty much every topic in astronomy. Has it been difficult to review such a range of subjects?

    A: It was a bit overwhelming at the beginning! Even for active astronomers it can be a challenge to know the most up-to-date research in every area. For me, this was partly why I wanted to be involved — to get back in touch with all of astronomy. And I’ve learned so much! I went through all my studies again and began recovering all this information.

    The interesting thing is that when I started as an astronomer back in the eighties, the science was at a completely different stage. Since then astronomy has progressed an almost unbelievable amount and there have been so many incredible discoveries. There is so much modern science that is hugely important now that we knew little about twenty years ago; take black holes, gravitational waves, and dark energy for example. I’m so pleased to have had the opportunity to catch up on some of the things I missed — but it required a lot of hard work!

    Of course, when reviewing content for the ESO Supernova, I have to check that all the numbers and facts are reported correctly, and in order to do that I cross-check and read a lot of scientific papers. It is so important that all our information is accurate, because it is our duty to inform the public.

    Q: What excites you most about the ESO Supernova?

    A: The reason I volunteered in the first place was to give tours to the students, in particular secondary school students, given my past as a high school maths teacher. I love interacting with them and telling them all about astronomy and science. When I first started at ESO, I volunteered with Italian kids, guiding them around the ESO Headquarters and even showing them a movie about the construction of ESO’s Very Large Telescope. This was really exciting — even watching a movie was very spectacular back then!

    We always put time aside for the students to ask astronomers questions, and I just loved that. But now, with the Supernova, I am supported by a hugely impressive exhibition, making it easier to impress the public, much more than I did just with just a VHS back in 1994!

    Q: What is your favourite thing about being a Science Liaison at ESO?

    A: Astronomy is intrinsically wonderful, with every image being so beautiful and impressive. But I love to be able to explain that there is so much more behind the beauty, and using that to inspire young people to go into science, or just to ask big questions and think about their place in the Universe.

    Science is about solving a mystery, and it’s great to give people a sense of the scientific approach — I like to encourage people to question what’s around them and maybe even to be more critical about what they might hear in the news.

    With the Science Liaison work, I always think critically. I take everything I read a sentence at a time, looking at each word and asking if this is the best word to use, the best way to describe an idea. I look at everything with doubt, not because I don’t trust what someone has written, but because it helps you critically analyse what you are looking at, and make it better.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Visit ESO in Social Media-

    Facebook

    Twitter

    YouTube

    ESO Bloc Icon

    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 VLT at Cerro Paranal in the Atacama Desert, •ANTU (UT1; The Sun ),
    •KUEYEN (UT2; The Moon ),
    •MELIPAL (UT3; The Southern Cross ), and
    •YEPUN (UT4; Venus – as evening star).
    elevation 2,635 m (8,645 ft) from above Credit J.L. Dauvergne & G. Hüdepohl atacama photo,


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

    ESO VLT 4 lasers on Yepun


    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.

    ESO/NRAO/NAOJ ALMA Array in Chile in the Atacama at Chajnantor plateau, at 5,000 metres

    ESO/E-ELT,to be on top of Cerro Armazones in the Atacama Desert of northern Chile. located at the summit of the mountain at an altitude of 3,060 metres (10,040 ft).


    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

    ESO Speculoos telescopes four 1m-diameter robotic telescopes at ESO Paranal Observatory 2635 metres 8645 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 10:31 am on June 2, 2019 Permalink | Reply
    Tags: "Astronomical failures", , , , , ESOblog   

    From ESOblog: “Astronomical failures” 

    ESO 50 Large

    From ESOblog

    1

    We want to share a secret: scientists fail all the time. A lot of scientific research leads to a “null” result, meaning that it is not a discovery. And though these results are vital steps on the road to discovery, they are rarely published, meaning that a huge chunk of science goes missing. But unfortunately for the following scientists, some failures are so dramatic that they go down in history.

    1. When the world conspires against you — Guillaume Le Gentil and the curse of Venus

    Often, our endeavours rely on factors outside our control and, while some challenges can be overcome, sometimes you can be downright unlucky. That is how you might describe Guillaume Le Gentil, who set out in the eighteenth century to measure the transit of Venus in order to calculate the size of the Solar System. The phenomenon occurs in pairs — with Venus transiting twice in the astronomically short timeframe of eight years. As adjacent pairs happen less frequently than once every hundred years; this was Le Gentil’s only chance. He travelled to the other side of the world, where the transits would be visible, but an extraordinary series of misfortunes befell him; between wars and the weather, he was unable to measure the first transit, and unable to view the second one at all. After a difficult journey home, Le Gentil discovered that everyone back in France had assumed him dead, his belongings had been taken by relatives and his wife had remarried. Le Gentil became well-known for his memoirs and his other scientific studies, but this was probably little consolation as he watched his competitor Captain Cook revel in success.

    2. When teamwork lets you down — John Couch Adams and the elusive eighth planet

    In the early nineteenth century, Uranus was behaving strangely. The planet had been discovered forty years earlier, but its movements weren’t following the expected path, leading to speculation about an unseen planet beyond it, interfering with its orbit. The young astronomer John Couch Adams set out to discover this new eighth planet. He spent years making calculations of its location, some of them correct. But the observers just couldn’t find this planet, even though they saw it, and mistook it for a star! What we now know as Neptune was discovered soon afterwards by another team of astronomers. Disheartening as this must have been, Adams moved on, applying himself to other questions and making great discoveries, most notably that the spectacular Leonid meteor showers originate from the debris of comet Tempel-Tuttle.

    3. When you’re right for the wrong reasons — Albert Einstein and the cosmological constant

    Einstein’s name may be synonymous with genius, but even the great logician was not immune to error. When his equations of general relativity suggested the size of the Universe was changing, he added in a term, the cosmological constant, to make the equations compatible with the Universe being static, a widely-held assumption at the time. After Hubble discovered that the Universe was actually expanding, Einstein scrapped the constant, whose introduction became known as his biggest blunder. But it turned out that scrapping it was the real mistake. Decades later it transpired that, not only is the Universe expanding, but the expansion is accelerating. Describing this using the equations of general relativity again required the cosmological constant. So when Einstein made his great mistake, he unwittingly fixed his equations to fit a characteristic of the Universe that he would never know.

    4. When you bury your head in the sand — Fred Hoyle and the big bang

    One astrophysicist famously opposed the idea that the Universe had a beginning, and his sarcastic reaction has become embedded in our language. Fred Hoyle was one of the authors of the steady state model, which says that the Universe is pretty much the same as it always has been. When the Universe was found to be expanding, physicists extrapolated backwards to conclude that it started as something much smaller and denser, threatening Hoyle’s steady state model. Devoted to his theory, Hoyle flippantly dismissed the new proposal as a “Big Bang”. As evidence mounted for the Universe’s beginning, Hoyle refused to accept it, instead contriving ways in which a steady state Universe could explain new observations. Despite his vehement opposition, he left the biggest imprint on the public perception of the idea — the ‘big bang’ is quite a catchy name after all!

    2
    Major milestones in the Universe since the Big Bang occurred 14 billion years ago. Credit: NAOJ

    But failures still occur today in our quest to find out more about the Universe…

    5. When there is much more at stake — NASA and the Apollo disasters

    NASA’s famous Apollo missions led to what is arguably humanity’s most remarkable achievement: setting foot on the Moon. In attempting something that has never been done before, especially something so ambitious, mistakes are inevitable. However, as disheartening as failure normally is, it becomes infinitely more serious when people’s lives are in jeopardy. Tragically, failures in the Apollo 1 mission led to the fatalities of three crew members. In subsequent launches, it was absolutely vital to learn from those mistakes. Most of the later missions were successful, but spaceflight remained high-risk, as demonstrated by the Apollo 13 mission, when an oxygen tank exploded in space. After an unimaginably nail-biting period of trying to set the craft on a safe path to Earth, the crew made it back alive, partly thanks to safeguards built in after Apollo 1. While most missions have been successful, there have been spaceflight fatalities since, highlighting the paramount importance of vigilance when people’s lives depend on it, no matter how many successful missions have gone before.

    6. When the devil is in the detail —NASA and the imperial disaster

    Fortunately, the Mars Climate Orbiter was an unmanned spacecraft, allowing some humour to be found in the circumstances of its failure. Built by NASA to study the Martian atmosphere, it burned up and disintegrated after making it almost all the way to the red planet. The problem was in the communication of two pieces of code in the programming. One calculated the force, in imperial pounds, that the thrusters needed to exert, and another read these calculations — in metric Newtons! The spacecraft followed the wrong path at the wrong speed, and burned up in Mars’ atmosphere instead of going into orbit around the red planet. A unit conversion might have been the easiest part of programming the spacecraft, but its simplicity clearly didn’t negate its importance!

    3
    Mars Climate Orbiter

    7. All’s well that ends well — Short-sighted Hubble

    When the Hubble Space Telescope sent its first images home, they were blurry, not discerning in detail the celestial objects that it had been sent up to see. The problem was identified as an error in the primary mirror; a tiny error of just two microns in an instrument used in the mirror’s production had made the mirror too flat, rendering its images useless. Since bringing Hubble back was not an option, NASA and ESA decided to build an additional set of mirrors that could correct Hubble’s vision. The ‘spectacles’ were installed by astronauts on a special mission, and they worked, allowing Hubble to begin its distinguished career sending back sharp views of the distant Universe. This story tells us that failure doesn’t always mean the end. Often, with determination and creativity, mistakes are fixable.

    What we can be sure of is that mistakes are absolutely essential to progress; an adage often attributed to Einstein states “a person who never made a mistake never tried anything new”, and science is all about trying new things and pushing boundaries. The scientific method by which our knowledge progresses is built on taking what we think we know and testing it to its limits, seeing if it holds up, and being ready to change our ideas if it turns out to be wrong. So, filling in the backdrop of all the attention-worthy illustrious scientific achievements, it is really the failures that make this millennia-long endeavour to understand the thing that we call science.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Visit ESO in Social Media-

    Facebook

    Twitter

    YouTube

    ESO Bloc Icon

    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 VLT at Cerro Paranal in the Atacama Desert, •ANTU (UT1; The Sun ),
    •KUEYEN (UT2; The Moon ),
    •MELIPAL (UT3; The Southern Cross ), and
    •YEPUN (UT4; Venus – as evening star).
    elevation 2,635 m (8,645 ft) from above Credit J.L. Dauvergne & G. Hüdepohl atacama photo,


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

    ESO VLT 4 lasers on Yepun


    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.

    ESO/NRAO/NAOJ ALMA Array in Chile in the Atacama at Chajnantor plateau, at 5,000 metres

    ESO/E-ELT,to be on top of Cerro Armazones in the Atacama Desert of northern Chile. located at the summit of the mountain at an altitude of 3,060 metres (10,040 ft).


    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

    ESO Speculoos telescopes four 1m-diameter robotic telescopes at ESO Paranal Observatory 2635 metres 8645 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 3:45 pm on May 19, 2019 Permalink | Reply
    Tags: Another current focus area is lasers which can be used to sharpen images by creating artificial stars in a technique called adaptive optics., Detectors are the key element of any astronomical instrument — they are like the eyes that see the light from the Universe., ESO’s Technology Development Programme, ESOblog, Lasers in Adaptive Optics, , To avoid wasted efforts we tend to focus our work into themes for example detectors or adaptive optics.   

    From ESOblog: “Shaping the future” 

    ESO 50 Large

    From ESOblog

    1

    17 May 2019

    Pushing the limits of our knowledge about the Universe requires the constant development of new trailblazing technologies. We speak to Mark Casali, former Head of ESO’s Technology Development Programme to find out more about how ESO keeps itself at the cutting-edge of scientific research.

    2
    Mark Casali

    Q. Firstly, could you tell us about ESO’s Technology Development Programme?

    A. We are a team of about a dozen people developing new technology that enables ESO to reach its ambitious scientific goals. This means we work on concepts with a fairly long timeframe — looking into completely innovative techniques and developing technology for astronomical instruments that will exist in the future, rather than those that exist today.

    Technology takes a long time to emerge, so we can’t wait to develop it until we want to produce an instrument that does something specific. Rather we need to already have the technology in place before the instrument is developed, in order to speed up production.

    One question people often ask is how we decide what new technology to explore. Of course, there are always more brilliant ideas than funds available, but our research is science-driven, meaning that when developing new technology we always focus on things that will eventually enable us to do the most exciting science.

    3
    The main mirror of the Extremely Large Telescope is visible at the centre of this image. It consists of 798 segments that together form a mirror 39 metres wide.
    Credit: ESO/L. Calçada/ACe Consortium

    Q. What kind of new technology are you developing at the moment?

    A. To avoid wasted efforts, we tend to focus our work into themes, for example detectors or adaptive optics. This means that we solve many problems in a single area so that area can move forward. This is more efficient than investing in several different areas and making only a small amount of progress in each.

    Detectors are the key element of any astronomical instrument — they are like the eyes that see the light from the Universe. Many very good detectors exist commercially, but often it’s useful to have detectors with really specific properties. So we put a lot of effort into developing new detectors.

    Another current focus area is lasers, which can be used to sharpen images by creating artificial stars, in a technique called adaptive optics. We also develop new mirror technology, for example mirrors that can change shape to create sharper images.

    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, a major asset of the Adaptive Optics system

    3
    The Paranal engineer Gerhard Hüdepohl checks the huge camera attached at the Cassegrain focus of VISTA, directly below the cell of the main mirror. VISTA´s powerful eye is a 3-tonne camera containing 16 special detectors sensitive to infrared light with a combined total of 67 megapixels. It will have widest coverage of any astronomical near-infrared camera. VISTA is the largest telescope in the world dedicated to surveying the sky at near-infrared wavelengths. Credit: ESO

    Q. Do you develop all of this new technology here at ESO?

    A. We actually only do about half of the technology development in house, and the other half is contracted out to external industry, universities or institutes around Europe. The decision to work on projects internally or externally depends on factors like whether we have the relevant expertise within our small team.

    Working with external partners is really a collaboration from which both parties benefit. We gain expertise, as well as a good quality product, because industry usually provides well-engineered products that are reliable and don’t break down easily. Also working with industrial partners gives us access to expensive machinery that we wouldn’t be able to afford ourselves for a single project. On the other hand, we are really looking to develop cutting-edge technology, so when we fund a company to develop something new, they really get ahead of the pack and could be the only company to be producing a certain product commercially. It’s a win-win for all involved!

    Working with industrial, academic and institutional partners also allows us to support our Member States, providing them with a return on the money they invest in ESO. Our collaborations with external partners occur through calls to tender and typically last about two years.

    Q. And what about the other way around? Does technology developed within ESO ever go on to have commercial success?

    A. Occasionally, yes! Although we don’t have a specific department for technology transfer, it does happen organically every now and then.

    For example, a couple of years ago we created a special laser called a Raman fibre laser that is used to create an artificial laser guide star by exciting sodium atoms high up in Earth’s atmosphere. We then signed a license agreement with two commercial partners for them to use this novel laser technology.

    3
    ESO’s Raman fibre laser feeding the frequency-doubling Second Harmonic Generation unit,, which produces a 20W laser at 589 nm. The light is used to create an artificial laser guide star by exciting sodium atoms in the Earth’s atmosphere at 90 km altitude. ESO has signed an agreement to license its cutting-edge laser technology to two commercial partners, Toptica Photonics and MPB Communications. This marks the first time that ESO has transferred patented technology and know-how to the private sector, offering significant opportunities both for business and for ESO. Credit: ESO

    Q. The Technology Development Programme sounds like an interesting place to work. What experience do you have that made you a good fit to oversee such a department?

    A. After a PhD in astronomy and then a stint as a researcher, I got involved in telescope construction projects. I believe that this combination of scientific and technical understanding was really helpful in my role.

    I do agree that this is a great team to work in! Not only is it really interesting to bring ideas for revolutionary technology through to actual deliverables, but I also feel that it’s a very important part of ESO’s work. Without new and improved technology, we wouldn’t be able to continue to make new discoveries and remain at the forefront of astronomical research.

    Q. Isn’t ESO involved in the European Union’s ATTRACT initiative to develop new technology?

    A. ESO is indeed one of the partners in the ATTRACT consortium, which consists mostly of large European infrastructures like CERN and EMBL, as well as universities and some industrial partners. The consortium recently received funding from the European Commission to run a competition for ideas in detector and imaging technology. This could be applied to many different fields, for example detecting light for astronomical or medical applications, or imaging particles for particle physics applications.

    We received over 1200 technology development ideas, of which 170 will be awarded 100 000 euros each. After a year and a half of work on their projects, a few of these will receive funding for a scale-up project. Hopefully these will include some astronomy-related projects!

    Through ATTRACT, ESO is able to work with other big organisations to develop the European economy, and I believe that the initiative is improving lives by creating products, services, jobs and even new companies.

    Q. Is there anything else you’d like to mention?

    A. Two things. The first being that the future of technology development at ESO is very bright; it’s likely that our programme will be supported and continue to grow long into the future. The second is that anybody can look at the list of ESO-developed technologies online, which we keep updated so that the public can see where their money goes.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Visit ESO in Social Media-

    Facebook

    Twitter

    YouTube

    ESO Bloc Icon

    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 VLT at Cerro Paranal in the Atacama Desert, •ANTU (UT1; The Sun ),
    •KUEYEN (UT2; The Moon ),
    •MELIPAL (UT3; The Southern Cross ), and
    •YEPUN (UT4; Venus – as evening star).
    elevation 2,635 m (8,645 ft) from above Credit J.L. Dauvergne & G. Hüdepohl atacama photo,


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

    ESO VLT 4 lasers on Yepun


    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.

    ESO/NRAO/NAOJ ALMA Array in Chile in the Atacama at Chajnantor plateau, at 5,000 metres

    ESO/E-ELT,to be on top of Cerro Armazones in the Atacama Desert of northern Chile. located at the summit of the mountain at an altitude of 3,060 metres (10,040 ft).


    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

    ESO Speculoos telescopes four 1m-diameter robotic telescopes at ESO Paranal Observatory 2635 metres 8645 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 1:41 pm on May 3, 2019 Permalink | Reply
    Tags: , , , , , ESOblog, Predicting the future of the Universe by measuring the distance to our closest galactic neighbour   

    From ESOblog: “The first rung on the cosmic distance ladder” 

    ESO 50 Large

    From ESOblog

    Predicting the future of the Universe by measuring the distance to our closest galactic neighbour.

    Large Magellanic Cloud. Adrian Pingstone December 2003

    26 April 2019

    1

    In the most accurate measurement to any galaxy ever, a team of scientists recently calculated the distance to the Large Magellanic Cloud to an incredible precision of 1%. This research was carried out in the hope of gaining a better understanding of dark energy and the future of the Universe. And it worked. We speak to the lead scientist involved in this study — Grzegorz Pietrzyński — to find out more about the enormous implications of this extraordinary measurement.

    2
    Grzegorz Pietrzynski

    Q. First of all, why is it important to measure the distances to other galaxies?

    A. Since our ancient ancestors began thinking about the cosmos, measuring distances has been one of the most important, fascinating and challenging goals in astronomy. It’s much more than recognising the scale of the Universe; it also means understanding the physical nature of astronomical objects, and each significant improvement in the accuracy of the distance scale opens up whole new fields of astrophysical research.

    It is especially important to measure the distance to the Large Magellanic Cloud — also known as the LMC — because distances to all the other galaxies in the Universe are calibrated against this one.

    2
    The Large and Small Magellanic Clouds glow above one of the four Very Large Telescope Unit Telescopes. Credit: A. Tudorica/ESO

    Q. Could you expand upon what you mean by that?

    A. Measuring the distance to the LMC is the first step in what is known as the cosmic distance ladder, which is a succession of methods astronomers use to measure the distances to astronomical objects. It is called a ladder because the first step — measuring the distances to the closest galaxies — requires one technique. Measuring how far away slightly more distant galaxies are requires another technique that relies on the first technique. And so on.

    The first step is to measure the distances to pulsating stars called Cepheid variables. About 100 years ago, American astronomer Henrietta Swan Leavitt discovered that the intrinsic brightness — or luminosity — of a Cepheid variable is closely related to its pulsation rate, also known as its period. By comparing their apparent brightness as seen from Earth with the real brightness predicted by their pulsation rate, astronomers can find out how far away a Cepheid variable is. An object with a known brightness, such as this one, is called a standard candle.

    But to get an accurate distance, it is important to know the exact relationship between luminosity and pulsation rate. To calculate this relationship, astronomers have previously been using a technique called parallax to measure distances to individual Cepheids in the Milky Way.

    2
    Iconic image of Standard candle, objects with a known luminosity that can be used to gauge cosmic distances. Credit: NASA/JPL-Caltech

    But another way, and indeed currently the best way, to measure the period-luminosity relationship of Cepheids is to measure the distance to a galaxy with a rich population of these stars, for example the LMC.

    By calculating the precise distance to the LMC, and getting an accurate value for the Cepheid period-luminosity relationship, we can look at even more distant Cepheids, in galaxies further away. And in these galaxies another type of standard candle exists: bright stellar explosions called type Ia supernovae.

    We know the distances to these more distant galaxies because of the Cepheid period-luminosity relationship, meaning that we also know how far away the type Ia supernovae are, and therefore can calculate how bright they are intrinsically. And as type Ia supernova are so bright, we can also see them in even more distant galaxies, so we can then work out how far away these very distant galaxies are.

    Q. So by looking at type Ia supernova in even more distant galaxies, we find out more about the scale of the Universe?

    A. Exactly! But there’s a catch. The type Ia supernovae in more distant galaxies are further away than they would be in a static Universe, because the Universe is expanding. This was discovered in the early 20th century by Edwin Hubble, who explained the expansion using a value called the Hubble constant. And because of the difference in what the supernovae look like, and what they would look like in a static Universe, we can use them to probe the expansion of the Universe and calculate the Hubble constant.

    But after 100 years of trying to determine this value, it turned out that the most difficult and challenging step is the first one: to calibrate the Cepheid period-luminosity relationship. We aimed to do this more precisely than ever before using eclipsing binary stars to measure an accurate distance to the LMC, a galaxy which possesses a few thousands Cepheids. This enabled us to work out the period-luminosity relationship of Cepheids in the LMC very accurately.

    Q. Could you tell us more about how you measured the distance to the LMC?

    A. Well in 2013 I already worked with a team to measure this distance precise to 2% using eight eclipsing binary stars and several telescopes, including ESO’s 3.6-metre and New Technology Telescope. During each eclipse, the total brightness of the system dips, allowing us to measure the properties of the stars. By comparing their actual size with the size that they appear on the sky, we can calculate their distance from Earth.

    But 2% was not enough. In astronomy, we are always working to find out things with more precision. So this time round, we looked at 20 eclipsing binaries to find the distance much more precisely. It involved observing for several hundred nights over 20 years, using many different telescopes including ESO’s Very Large Telescope.

    Q. So what did you find the distance to be this time round?

    A. We found that the LMC is 1 497 000 000 000 000 000 kilometres away, with an uncertainty of just 1%, meaning that the actually value could be up to 1% larger or smaller than this value. It’s incredible to think that we can be so sure about the distance to something so far away!

    And based on this precise distance, we believe that we will be able to calculate the Hubble constant more accurately than ever before. Just recently a team of scientists used the Hubble Space Telescope to calculate it to a precision of 1.9% but we think that we will be able to get this down to 1.5%!

    Q. Could you explain more about why it is so important to know the value of the Hubble constant?

    A. Knowing the Hubble constant helps us find out how fast the Universe is accelerating, which effectively means that we can predict the future of the Universe. Will it expand forever? Will it stop accelerating and one day collapse? Astronomers now believe that it will expand forever, becoming colder and colder until it can no longer support life.

    In the 1990s, astronomers discovered that the expansion of the Universe is accelerating because of a mysterious phenomenon called dark energy. Since then, explaining dark energy has been a major challenge. But by becoming more certain about the Hubble constant, we will find out more about dark energy.

    We can also use the Hubble constant to find out lots of other information about the Universe, for example the amount of matter and radiation that exists. Therefore, an independent, highly accurate measurement of the Hubble constant is vital for making significant progress towards understanding cosmology in general.

    Furthermore, there’s another way to measure the Hubble constant using the cosmic microwave background radiation. But this gives a very different result and we have no idea why! Therefore it is extremely important to improve the precision and accuracy of the Hubble constant to investigate this discrepancy in more detail. If the discrepancy is confirmed, modern physics requires significant revision.

    4
    This illustration shows the three steps astronomers previously used to measure the expansion rate of the Universe to an unprecedented accuracy, reducing the total uncertainty to 2.4%. With the new LMC distance measurement (using eclipsing binaries as the first step rather than parallax), this uncertainty will reduce to just 1.5%.
    Credit: NASA, ESA, A. Feild (STScI), and A. Riess (STScI/JHU)

    5
    CMB per ESA/Planck

    Q. Are there any other implications of this result?

    A. One implication is that our new technique can be applied to verify how good other methods of measuring distances are. For example, ESA’s Gaia space observatory is using the parallax method to create a 3D map of the Milky Way.

    Parallax method ESA

    By comparing Gaia measurements to measurements obtained through our eclipsing binary method, we can figure out the accuracy of Gaia’s map.

    Nearby galaxies in general, and especially the LMC as the closest galaxy, are perfect laboratories for studying different objects and processes. But for many of these studies we need to know precise distances. With the advent of huge telescopes like the Extremely Large Telescope, we will be able to conduct studies of nearby galaxies with unprecedented accuracy, making it vital that we already know precisely how far away they are.

    Q. Is there anything else you would like to mention?

    A. I would like to thank many astronomers involved for interesting discussions, suggestions, and stimulation, the staff at La Silla, Paranal and Las Campanas for their excellent support during observations, and the funding agencies for their generous support.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Visit ESO in Social Media-

    Facebook

    Twitter

    YouTube

    ESO Bloc Icon

    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 VLT at Cerro Paranal in the Atacama Desert, •ANTU (UT1; The Sun ),
    •KUEYEN (UT2; The Moon ),
    •MELIPAL (UT3; The Southern Cross ), and
    •YEPUN (UT4; Venus – as evening star).
    elevation 2,635 m (8,645 ft) from above Credit J.L. Dauvergne & G. Hüdepohl atacama photo,


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

    ESO VLT 4 lasers on Yepun


    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.

    ESO/NRAO/NAOJ ALMA Array in Chile in the Atacama at Chajnantor plateau, at 5,000 metres

    ESO/E-ELT,to be on top of Cerro Armazones in the Atacama Desert of northern Chile. located at the summit of the mountain at an altitude of 3,060 metres (10,040 ft).


    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

    ESO Speculoos telescopes four 1m-diameter robotic telescopes at ESO Paranal Observatory 2635 metres 8645 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 1:12 pm on May 3, 2019 Permalink | Reply
    Tags: , , , , EHT and Messier 87, ESOblog   

    From ESOblog: “Modelling reality” 

    ESO 50 Large

    From ESOblog

    3 May 2019

    1

    The recent release of the first “image” of a black hole can’t have escaped your notice. But how can we use this image to find out about the physical characteristics of the black hole? …to unearth more details about these mysterious objects? The secret is in the simulations that theoretical physicists have spent years working on. Two theoreticians involved in the Event Horizon Telescope (EHT) tell us more.


    Luciano Rezzolla is a theoretician in the Event Horizon Telescope collaboration. He uses sophisticated numerical simulations to deduce the characteristics of the black hole.
    Credit: ESO

    Name: Luciano Rezzolla
    Job: Professor of relativistic astrophysics and numerical relativity at Goethe University, Germany
    Roles in the EHT project: Theoretician

    What were the biggest challenges you faced whilst getting to this result?

    Early on, it was already very clear that our task as theorists in the EHT collaboration was to provide a physical explanation for what would be observed using the telescopes, and to use sophisticated numerical simulations to deduce the properties of the black hole. We were always aware that this would be a huge challenge. So following this strategy, we performed the most extensive numerical exploration of the dynamics of the plasma surrounding the black hole, to figure out how it swirls around and shines when it actually falls onto the black hole.

    We considered hundreds of different physical and astrophysical scenarios by studying different properties (masses and spins) of the black hole, but also different thermodynamic properties of the orbiting plasma. For each scenario we constructed thousands of synthetic images that could theoretically be the result of the complex bending and lensing of the light near the black hole. At the end of this effort we had built a library of more than 60,000 synthetic images!

    We had thought that based on this huge image library, we would easily be able to decide which scenario was the correct one. But what we instead realised is that many combinations of physical parameters can lead to simulated images that, once blurred with the telescope resolution, would match the actual observed image very well.

    This was a relief because it meant that whatever our conclusions on the properties of the observed image, these would be very robust. But although we were very confident that this was a black hole, we weren’t sure what its characteristics would be. This meant that we had to go back to the blackboard and sharpen the techniques we were using to compare the theory with the observations. In practice this has meant a lot of sleepless nights especially for Dr. Fromm, a member of our team in Frankfurt, who eventually managed to single out the simulated images that best matched the observations after exploiting a sophisticated genetic algorithm.

    Once we established what physical properties were needed to create a “best-match simulated image”, we could guess the real physical properties of the black hole. Therefore we managed to explain the physical origin of the emission ring surrounding the black hole — a very rewarding and reassuring feeling!


    Monika Mościbrodzka is co-coordinator of a research group that looks at the polarisation of the light from the ring surrounding the black hole. She also contributes significantly to theoretical modelling and interpretation of EHT data. Credit: ESO

    Name: Monika Mościbrodzka
    Job: Assistant professor, Radboud University, the Netherlands
    Roles in the EHT project: Co-coordinator of a research group that looks at polarisation of the light from the ring surrounding the black hole. Leader of theoretical research, major contributor to theoretical modelling and interpretation of EHT data.

    What emotions have you been through whilst getting to this result?

    My work as a theoretical astrophysicist in the EHT project focuses on modelling the appearance of black holes depending on what is around them. Over many years of my academic research prior to making the EHT observations I sort of got used to seeing simulated pictures of black holes.

    Then when the EHT data was calibrated and ready for imaging, I joined one of the imaging teams out of curiosity. I sensed that this would be a perfect opportunity for a theorist to get in touch with reality. This experience turned out to be very rewarding. It is hard to find words that describe the emotions that I felt when I first saw the initial images of M87 last summer. These images were MIND BLOWING.

    But as a theorist I felt an additional thrill when looking at the image. The black hole appeared almost exactly how I imagined it to be, just exactly how I had predicted it would look in my models of its host galaxy, Messier 87. So in some sense this experiment did not reveal something completely unexpected.

    During the press conference in Brussels, I was honestly moved. After months of secret-keeping, we could finally speak openly about our black hole, this extraordinary wonder of nature, with the rest of the world. I feel extremely privileged to be a part of the EHT team that made such a big impact on science. It’s truly a life-changing experience.

    The next step for EHT scientists is to analyse the polarisation of light from the ring that surrounds the black hole. This will give us critical information about the magnetic fields at the black hole’s event horizon, helping us to understand the exact nature of the light that is visible in the image that we see. We could start to discover, for example, how exactly this light is produced.

    Links

    ESO EHT web page
    ESO EHT blog post: Photographing a black hole
    ESO EHT blog post: Behind the black hole
    EHT blog
    Goethe University: Making black holes visible
    Papers:
    Paper I: The Shadow of the Supermassive Black Hole
    Paper II: Array and Instrumentation
    Paper III: Data processing and Calibration
    Paper IV: Imaging the Central Supermassive Black Hole
    Paper V: Physical Origin of the Asymmetric Ring
    Paper VI: The Shadow and Mass of the Central Black Hole

    Science Snapshots showcases quirky or interesting scientific results using ESO telescopes from the larger scientific community. Find more interviews with astronomers and stories about astronomical research at ESO here on the ESOblog.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Visit ESO in Social Media-

    Facebook

    Twitter

    YouTube

    ESO Bloc Icon

    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 VLT at Cerro Paranal in the Atacama Desert, •ANTU (UT1; The Sun ),
    •KUEYEN (UT2; The Moon ),
    •MELIPAL (UT3; The Southern Cross ), and
    •YEPUN (UT4; Venus – as evening star).
    elevation 2,635 m (8,645 ft) from above Credit J.L. Dauvergne & G. Hüdepohl atacama photo,


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

    ESO VLT 4 lasers on Yepun


    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.

    ESO/NRAO/NAOJ ALMA Array in Chile in the Atacama at Chajnantor plateau, at 5,000 metres

    ESO/E-ELT,to be on top of Cerro Armazones in the Atacama Desert of northern Chile. located at the summit of the mountain at an altitude of 3,060 metres (10,040 ft).


    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

    ESO Speculoos telescopes four 1m-diameter robotic telescopes at ESO Paranal Observatory 2635 metres 8645 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 1:55 pm on April 22, 2019 Permalink | Reply
    Tags: , , , , ESOblog, , The Black Hole of Messier 87   

    From ESOblog: “Behind the black hole Messier 87” 

    ESO 50 Large

    From ESOblog

    The first image of a black hole, Messier 87 Credit Event Horizon Telescope Collaboration, via NSF 4.10.19

    Imaging a black hole is no easy task. The Event Horizon Telescope (EHT) project involved over 200 scientists from around the world, and without their hard work, dedication, and imagination, such a feat would never have been possible. Three of these scientists talk about how it feels to be part of an international collaboration that has recently turned the seemingly-impossible into a reality.


    Sera Markoff is a member of the EHT Science Council, co-coordinator of the Multiwavelength Working Group, co-coordinator of Proposals Working Group and leads a research group that contributed to theoretical modelling and interpretation.
    Credit: ESO/BlackHoleCam /Radboud University/ Cristian Afker/Cafker Productions. Produced by: Cristian Afker/Cafker Productions /ESO.

    Name: Sera Markoff
    Job: Professor of Theoretical High Energy Astrophysics, University of Amsterdam, the Netherlands
    Roles in the EHT project: Member of the Science Council, co-coordinator of the Multiwavelength Working Group, co-coordinator of Proposals Working Group and leads a research group that contributed to theoretical modelling and interpretation.

    What has been the most exciting part of this project so far?

    Without a doubt, the most exciting part of the project so far was to make the big discovery — to show the world that black holes really exist, and to quite literally be able to gaze down into that sinkhole. I have been working on modeling black holes in one way or another for most of my career, and I think that one gets a bit blasé at some point, since we use the concept of black holes all the time without having ever actually seen one directly. To really “look it in the eye” is fascinating but also a bit maddening! And now I dream of seeing what it looks like close up, without the distortions of a telescope in between! I want to understand how such a thing can be possible, when our understanding of physics at the moment is not complete and cannot yet explain gravity or black holes at a quantum level.

    I also found working with a big team focused on a single, major goal very exciting. There were so many researchers, particularly PhD and postdoctoral students who dedicated a huge amount of time to making this project a success, and I am very happy to see it pay off for them, since it will boost their careers massively.


    Heino Falcke, of Radboud University in the Netherlands, coined the term “black hole shadow” and was the scientists that originally came up with the idea of imaging a black hole using millimetre-wavelength Very Large Baseline Interferometry (VLBI). Heino is currently chair of the EHT science council and co-Principal Investigator of the European Research Council Synergy Grant BlackHoleCam that co-funded the EHT.
    Credit: ESO/BlackHoleCam /Radboud University/ Cristian Afker/Cafker Productions. Produced by: Cristian Afker/Cafker Productions /ESO.

    Name: Heino Falcke
    Job: Professor of Astroparticle Physics and Radio Astronomy, Radboud University, the Netherlands
    Roles in the EHT project: Coiner of the term “black hole shadow” and proposer to try to image a black hole using millimetre-wavelength Very Large Baseline Interferometry (VLBI). Chair of the EHT science council and co-Principal Investigator (together with Luciano Rezzolla and Michael Kramer) of the European Research Council Synergy Grant BlackHoleCam that co-funded the EHT.

    How did it feel when you saw the first image of the black hole?

    Twenty-five years ago, back in the pioneering days of millimetre-wavelength VLBI, I was doing my PhD at the Max-Planck Institute in Bonn. Modeling the black hole at the centre of the Milky Way, I realised that light of millimetre-wavelength or below would be emitted from close to the black hole’s event horizon. Alas, black holes are surprisingly tiny, so the event horizon seemed too small to see, even with an Earth-sized telescope.

    But then, one lonely afternoon in the library, I stumbled across an article that described how a black hole would look much bigger when illuminated from behind. I was electrified. I hadn’t considered gravitational lensing — that a black hole could actually magnify itself due to the bending of light by its own mass. This would make it look much bigger!

    I worked with two other scientists, Eric Agol and Fulvio Melia, to calculate what a black hole would look like if it was engulfed by a glowing transparent region and, lo and behold, we found that a dark area would appear, surrounded by a bright ring that would be just large enough to be detected. We called the dark area the “shadow of the black hole” and claimed it could be detected within the following ten years!

    Well, not quite. But 19 years later my own PhD student, Sara Issaoun, showed me the first raw data from the EHT project. The plot was a complicated and incomplete one-dimensional mathematical transformation of an image. But doing the mathematical inversion in my head, as we have all learned to do during this project, my heart started beating faster: this could be a ring!

    Weeks later, we could finally make the actual image and there it was — the shadow inside a ring. All these years after predicting that it would be possible to image a black hole in this way, this huge collaboration of scientists had finally done so! For an hour I felt like I was hovering above the ground, but then it hit me that we still had many rough months to go before we could be certain. I sent up a brief “thank you” prayer to heaven and continued the day with a smile on my face.


    Sara Issaoun, of Radboud University in the Netherlands observed using one of the eight EHT telescopes, the Submillimeter Telescope (SMT). Sara also contributed to data processing and calibration, as well as the imaging efforts.
    Credit: ESO/BlackHoleCam /Radboud University/ Cristian Afker/Cafker Productions. Produced by: Cristian Afker/Cafker Productions /ESO.

    Name: Sara Issaoun
    Job: Graduate student at Radboud University, the Netherlands
    Roles in EHT project: EHT observing staff at the Submillimeter Telescope (SMT), core contributor in EHT data processing and calibration, active contributor in imaging efforts

    Describe some of the emotions you went through whilst getting to this result.

    Although I’ve gone through many emotions during this project, the most common is probably exhaustion! During our 2017 observing campaign at the SMT in Arizona, I was excited to be carrying out observations, hearing the equipment roar as blinking green lights indicated the successful collection of data. And the weather was excellent, meaning that we could observe on multiple days in a row. The downside to this? Back-to-back 16 hour observing shifts, with preparation time in between, and very, very little sleep. Combined with the high altitude, this made it an exhausting expedition. But then I saw the messages rolling in from Chile, the South Pole, Spain, Mexico and Hawaii, which made me feel part of a truly historic moment; all these telescopes and people, all staring towards the centre of Messier 87 — just one galaxy in amongst several trillion that exist in the Universe.

    After we packed up our recordings and drove down the mountain, it took a few months before we got the results of our observations. But when we heard that the telescope had worked well, and that we had worked well, I felt extreme relief.

    But it also meant that our data was ready for calibration, which involved a lot more hard work, exhaustion and stress. I will never forget the day when I first saw the fully calibrated data; the quality was so high that it took only seconds for me to understand that this could lead to a groundbreaking image. Four imaging teams worked separately to create the final image, and I was part of one of these teams.

    A mere few minutes after I started processing the data, I saw the ring structure appear. It was jaw-dropping, even thrilling. Six weeks of hard work passed, during which we perfected our image and improved our understanding of the data, before all the imaging teams met at a workshop in July 2018. We were all extremely anxious to see if everyone had seen the same structure. Once again, it turned out that everyone saw the same thing, even though we had all been using different software. This was real. This was it. The room filled with applause and laughter and general awe at being part of this incredible project. We were fully aware of the huge amount of work ahead of us, to understand what we were seeing and convince the rest of the community, but that moment was really special.

    See the full article here .


    Katie Bouman “Imaging a Black Hole with the Event Horizon Telescope”

    Event Horizon Telescope Array

    Arizona Radio Observatory
    Arizona Radio Observatory/Submillimeter-wave Astronomy (ARO/SMT)

    ESO/APEX
    Atacama Pathfinder EXperiment

    CARMA Array no longer in service
    Combined Array for Research in Millimeter-wave Astronomy (CARMA)

    Atacama Submillimeter Telescope Experiment (ASTE)
    Atacama Submillimeter Telescope Experiment (ASTE)

    Caltech Submillimeter Observatory
    Caltech Submillimeter Observatory (CSO)

    IRAM 30m Radio telescope, on Pico Veleta in the Spanish Sierra Nevada,, Altitude 2,850 m (9,350 ft)


    Institut de Radioastronomie Millimetrique (IRAM) 30m

    James Clerk Maxwell Telescope interior, Mauna Kea, Hawaii, USA
    James Clerk Maxwell Telescope interior, Mauna Kea, Hawaii, USA

    Large Millimeter Telescope Alfonso Serrano
    Large Millimeter Telescope Alfonso Serrano

    CfA Submillimeter Array Mauna Kea, Hawaii, USA, Altitude 4,080 m (13,390 ft)

    Submillimeter Array Hawaii SAO

    ESO/NRAO/NAOJ ALMA Array
    ESO/NRAO/NAOJ ALMA Array, Chile

    South Pole Telescope SPTPOL
    South Pole Telescope SPTPOL

    NSF CfA Greenland telescope

    Future Array/Telescopes

    Future Array/Telescopes

    IRAM NOEMA in the French Alps on the wide and isolated Plateau de Bure at an elevation of 2550 meters, the telescope currently consists of ten antennas, each 15 meters in diameter.interferometer, Located in the French Alpes on the wide and isolated Plateau de Bure at an elevation of 2550 meters

    NSF CfA Greenland telescope

    NSF CfA Greenland telescope


    Greenland Telescope

    ARO 12m Radio Telescope, Kitt Peak National Observatory, Arizona, USA, Altitude 1,914 m (6,280 ft)


    ARO 12m Radio Telescope


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Visit ESO in Social Media-

    Facebook

    Twitter

    YouTube

    ESO Bloc Icon

    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 VLT at Cerro Paranal in the Atacama Desert, •ANTU (UT1; The Sun ),
    •KUEYEN (UT2; The Moon ),
    •MELIPAL (UT3; The Southern Cross ), and
    •YEPUN (UT4; Venus – as evening star).
    elevation 2,635 m (8,645 ft) from above Credit J.L. Dauvergne & G. Hüdepohl atacama photo,


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

    ESO VLT 4 lasers on Yepun


    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.

    ESO/NRAO/NAOJ ALMA Array in Chile in the Atacama at Chajnantor plateau, at 5,000 metres

    ESO/E-ELT,to be on top of Cerro Armazones in the Atacama Desert of northern Chile. located at the summit of the mountain at an altitude of 3,060 metres (10,040 ft).


    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

    ESO Speculoos telescopes four 1m-diameter robotic telescopes at ESO Paranal Observatory 2635 metres 8645 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 11:54 am on April 12, 2019 Permalink | Reply
    Tags: , , , , , ESOblog,   

    From ESOblog: “Photographing a black hole” 

    ESO 50 Large

    From ESOblog

    Messier 87 supermassive black hole from the EHT

    10 April 2019

    Today, the Event Horizon Telescope team announced that they have “imaged” a black hole for the first time ever. The black hole lies 55 million light-years away at the centre of the massive galaxy Messier 87. Such an incredible feat has taken decades of collaboration between people and telescopes around the world — requiring patience, persistence and perseverance. And the story doesn’t end here. Rubén Herrero-Illana and Hugo Messias, two ESO/ALMA fellows, tell us about how they were involved at the front line of this endeavour, and about the enormous efforts involved in such an astonishing achievement.

    Q. Firstly, could you tell us a bit more about the Event Horizon Telescope?

    Rubén Herrero-Illana (RHI): The Event Horizon Telescope — or EHT — is an experiment that uses eight telescopes around the world to observe some of the closest supermassive black holes with an unprecedented resolution. The scientific goal of the EHT is to find out what happens in the extreme environments around supermassive black holes, which are some of the most intriguing objects in the Universe.

    The EHT uses a technique called very long baseline interferometry (VLBI), in which we make several radio telescopes, separated by thousands of kilometres, observe the same object in the sky simultaneously. By combining the signals from each telescope in a particular way, we are able to mimic a telescope as large as the Earth. To explain just how amazing this is — the resolution that we obtain this way would allow us to stand in Chile and see through the eye of a needle in Spain!

    The participating stations in the EHT include ESO’s APEX telescope and ALMA, which ESO is a partner in.

    3
    Consisting of 66 antennas, ALMA is revolutionising the way that we see the Universe. As well as helping to image black holes, ALMA gives astronomers an unprecedented capability to study the cool Universe — molecular gas and dust as well as the relic radiation of the Big Bang. ALMA studies the building blocks of stars, planetary systems, galaxies, and life itself. Credit: ESO/S. Guisard (www.eso.org/~sguisard)

    Q. What were your roles in the project?

    RHI: For the last two years, we have been involved in the preparation and execution of the observations at ALMA. This involves actually observing on site using the telescope. We have also been part of the group that calibrates the ALMA data and checks their quality before sending them to the correlators, which are the supercomputers th combine the signals from every station.

    Q. What do you mean by ‘calibrating’ the data?

    Hugo Messias (HM): We correct the raw data from the telescope for any system imperfection or inhomogeneous behavior. There are many things to correct for: for example, light is distorted and partially absorbed as it travels through Earth’s turbulent atmosphere, making the image blurrier and fainter. And even though the telescope system is state-of-the-art, it may introduce other imperfections in the light we receive from the Universe. We need to correct for all of these things to ensure that we have great data!

    Q. So has it been difficult to schedule observations of the black hole at the centre of Messier 87?

    4
    Analogue signals collected by the antenna are converted to digital signals and stored on hard drives together with the time signals provided by atomic clocks. The hard drives are then flown to a central location to be synchronised. Credit: ALMA (ESO/NAOJ/NRAO), J.Pinto & N.Lira

    RHI: Yes! The individual telescopes that make up the EHT are not fully dedicated to the EHT project; they are cutting-edge telescopes that astronomers use all year long to observe a variety of different objects. Once per year, all these telescopes agree to create a gap in their schedules to observe together as part of the EHT. But the observing time is very limited.

    During observing campaigns, we must decide every day if an observation is going to be triggered or if we are going to wait until the next day. If we decide to wait, all stations will continue their usual observations, but if we get the green light, everyone will observe the agreed black hole targets and a part of the valuable time set aside for the EHT is consumed. This decision is mainly based on the weather forecast, and it is a tough one. After all, it is not that common to have good weather in so many places in both hemispheres at the same time! Furthermore, there are some small details that make things even more interesting. For instance, communication with the South Pole Telescope in the middle of Antarctica is not steady, but restricted to the limited windows when telecommunication satellites pass above the telescope. Last minute decisions are not always an option.

    HM: During the observations, a plan is sketched and distributed among all observing facilities. This schedule has to be followed to very precise timings, so we know that all telescopes are pointing at the same source at the same time. When finished, the data obtained are sent to the data-combining correlators. The challenge is that some of the stations might have been shut due to poor weather conditions, or that the data take months to arrive. An extreme example of the latter is that data from the South Pole Telescope arrive at the correlators only 6–8 months after observation!

    Q. Thirteen partner organisations and more than 200 people are involved in this project. Why does it require such a huge international effort?

    HM: Imaging a black hole is incredibly difficult. Even though the black hole at the centre of Messier 87 is 6.5 billion times the mass of the Sun, it is very dense, and therefore relatively small. And it is 55 million light-years away, so from Earth it looks tiny! We have been trying to image the event horizon — the ‘point of no return’ around a black hole, beyond which light can’t escape. But to discern something so small, we need a huge telescope. And as we are measuring light that has wavelengths on the order of millimetres, we need a telescope the size of the Earth! This is physically impossible, so we used interferometry — which is the same technique that ALMA uses on a smaller scale — to connect telescopes around the globe to mimic an Earth-sized telescope. And that takes a huge international effort.

    Q. How are the telescopes synchronised?

    RHI: When using the technique of interferometry, it is essential to combine the signals from each telescope at the exact same time. One way to ensure the synchronisation is to connect every station with a fibre-optic link to a central supercomputer. But considering the remote locations of the EHT telescopes, this would clearly not have been an option! Instead, each telescope was equipped with an ultra-precise hydrogen maser atomic clock that precisely timed each observation. This made it possible to combine data later on.

    4
    The locations of the participating telescopes of the Event Horizon Telescope (EHT) and the Global mm-VLBI Array (GMVA). Credit: ESO/O. Furtak

    Q. Was it difficult to collaborate with other institutions all around the world?

    RHI: There are always challenges in coordination and communication among the many different people working in an observatory: astronomers, engineers, administrators and computing teams, to name just a few. Everyone must work together towards the same goal. ALMA is a huge observatory, with hundreds of workers from more than ten different countries, and some of the other observatories involved in the EHT project are almost as big. Now imagine eight of these observatories working together on a time critical, cutting-edge project, and you will get a grasp of how much fun a project like the EHT can be!

    Q. How does it feel to be part of an international collaboration that has made such an incredible discovery?

    HM: I feel honoured, proud, fulfilled, and hopeful. The latter is more related to the fact that we are showing that, despite the cultural differences, a team comprising individuals with distinct backgrounds had a common goal, and achieved it. That teaches the world another key lesson, besides the one being reported.

    Q. Is there anything else you would like to mention?

    HM: Aside from the people included in the author list of the papers, many other individuals enabled this discovery to happen. We are not only “standing on the shoulders of giants” who carved out the path towards the techniques and technology we currently use, but also on shoulders of hard-working people who build and maintain the antennas, correlators and software at these remote sites. This is what enabled the discovery to happen. To them, I say a big thank you, as well as to the curious society that provided the will and, of course, the funding. These contributions were key to making this feat a reality!

    See https://sciencesprings.wordpress.com/2019/04/10/from-european-southern-observatory-astronomers-capture-first-image-of-a-black-hole/ for lists with links.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Visit ESO in Social Media-

    Facebook

    Twitter

    YouTube

    ESO Bloc Icon

    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 VLT at Cerro Paranal in the Atacama Desert, •ANTU (UT1; The Sun ),
    •KUEYEN (UT2; The Moon ),
    •MELIPAL (UT3; The Southern Cross ), and
    •YEPUN (UT4; Venus – as evening star).
    elevation 2,635 m (8,645 ft) from above Credit J.L. Dauvergne & G. Hüdepohl atacama photo,


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

    ESO VLT 4 lasers on Yepun


    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.

    ESO/NRAO/NAOJ ALMA Array in Chile in the Atacama at Chajnantor plateau, at 5,000 metres

    ESO/E-ELT,to be on top of Cerro Armazones in the Atacama Desert of northern Chile. located at the summit of the mountain at an altitude of 3,060 metres (10,040 ft).


    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

    ESO Speculoos telescopes four 1m-diameter robotic telescopes at ESO Paranal Observatory 2635 metres 8645 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

     
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