Bild der Woche

5. Dezember 2011: This telescope is an important new component of the Four Laser Guide Star Facility, which will sharpen the already excellent vision of ESO’s Very Large Telescope (VLT). Four powerful 20-watt lasers, fired to an altitude of 90 kilometres up in the atmosphere, will help the VLT correct the image distortion caused by turbulence in the air. The Netherlands Organisation for Applied Scientific Research (TNO) is developing the launch telescopes through which the laser beams will be fired. The first of these laser launch telescopes — known as the Optical Tube Assembly — is seen here in the cleanroom at TNO’s Van Leeuwenhoek Laboratory in Delft, the Netherlands, having recently held its Acceptance Review. A special anti-reflective coating gives the lens on the telescope a distinctive blue hue. The photograph was taken by Fred Kamphues, who appears on the left. He is project manager for the Optical Tube Assembly, and is ...

28. November 2011: Dieses Bild vom Very Large Telescope (VLT) der ESO, zeigt eine wirklich bemerkenswerte Galaxie, die als NGC 3621 bekannt ist. Zunächst einmal ist sie eine reine Scheibengalaxie. Wie andere Spiralgalaxien besteht sie aus einer flachen Scheibe, die von Linien dunklen Materials durchzogen wird und hat ausgeprägte Spiralarme, in denen sich junge Sterne in Haufen bilden (die blauen Flecken, die man im Bild sehen kann). Aber während die meisten Spiralgalaxien eine zentrale Ausbuchtung haben (den sogenannten Bulge), eine große Ansammlung alter Sterne, die in eine kompakte, sphärische Region gepackt sind, hat NGC 3621 keine. Auf diesem Bild wird klar, dass es einfach einen Helligkeitsanstieg zum Zentrum hin gibt, aber keinen wirklichen Bulge wie zum Beispiel den in NGC 6744 (eso1118). NGC 3621 ist auch interessant, weil man davon ausgeht, dass sich in ihrem Zentrum ein aktives supermassereiches Schwarzes Loch in ihrem Zentrum befindet, das Materie verschluckt und Strahlung produziert. Dies ist ...

21. November 2011: At sunset, the sky is often painted with an array of oranges, reds and yellows, and even some shades of pink. There are, however, occasions when a green flash appears above the solar disc for a second or so. One such occurrence was captured beautifully in this picture taken from Cerro Paranal, a 2600-metre-high mountain in the Chilean Atacama Desert, by ESO Photo Ambassador Gianluca Lombardi. Cerro Paranal is home to ESO’s Very Large Telescope. The green flash is a rather rare phenomenon; seeing such a transient event requires an unobstructed view of the setting (or rising) Sun and a very stable atmosphere. At Paranal the atmospheric conditions are just right for this, making the green flash a relatively common sight (see for example eso0812). But a double green flash such as this one is noteworthy even for Paranal. The green flash occurs because the Earth’s atmosphere works like a ...

14. November 2011: In the foothills of the Chilean Andes, at an altitude of 2900 metres, the Operations Support Facility (OSF) for the Atacama Large Millimeter/submillimeter Array (ALMA) is a hive of activity. This photograph shows engineers moving a heavyweight antenna at night — with the help of a special 28-wheel transporter — and illustrates how work at ALMA continues around the clock. The antenna, one of 25 provided for the ALMA project by ESO, is being moved into position next to antennas from the other ALMA partners to be tested and equipped with highly sensitive detectors. When completed, ALMA will consist of 66 12-metre and 7-metre antennas that will work together as a giant radio telescope observing at millimetre and submillimetre wavelengths. The facility will allow astronomers to study our cosmic origins by probing the first stars and galaxies, and imaging the formation of planets. The telescope is being constructed on Llano ...

7. November 2011: This image shows some of the GRAAL instrument team, inspecting GRAAL’s mechanical assembly in the integration hall of ESO’s Headquarters in Garching bei Munchen, Germany. GRAAL, which will be installed on ESO’s Very Large Telescope (VLT) on Cerro Paranal in Chile, is designed to improve the vision of the VLT’s already excellent HAWK-I camera even further. GRAAL stands for GRound layer Adaptive optics Assisted by Lasers. It will use the technique of adaptive optics to improve the quality of images by compensating for turbulence in the lower layers of the atmosphere, up to an altitude of 1 kilometre. GRAAL will form part of the observatory’s next generation Adaptive Optics Facility (AOF). The VLT already uses a powerful laser beam to create an artificial guide star, 90 kilometres up in the atmosphere. The current adaptive optics systems use this guide star as a reference to remove the effect of turbulence in ...

31. Oktober 2011: Ein leuchtender Laserstrahl wird von dem Very Lage Telescope der Europäischen Südsternwarte ausgesandt. Indem er hell in den chilenischen Nachthimmel ragt, soll er den Astronomen helfen, die weiten Ge lde des Kosmos zu erforschen. Der ESO-Fotobotschafter Gerhard Hüdepohl war vor Ort, um diesen Moment der modernen Wissenschaft in Aktion in einem beeindruckenden Portrait festzuhalten. Wir haben wohl alle schon hoch an den Nachthimmel geblickt und die Sterne funkeln sehen, da die turbulente Atmosphäre der Erde ihr Licht zum Flackern bringt. Dies ist zweifellos ein schoner Anblick, der jedoch zu Problemen für Astronomen führt, die eine möglichst klare Sicht benötigen. Um dies zu erreichen, nutzen professionelle Astronomen etwas, das sich anhört als käme es aus dem Genre des Science-Fiction: ein Laserleitstern, der einen künstlichenStern 90 km über der Erdoberfläche erzeugt. Die Art und Weise, auf die das erreicht wird, ist durchaus bemerkenswert: Natriumatome, die sich hoch in der Mesosphäre der Erde ...

24. Oktober 2011: Nicht alle Spiralgalaxien müssen perfekt aussehen, um Blicke auf sich zu ziehen. Messier 96, auch als NGC 3368 bekannt, beweist dies: Der Kern ist gegenüber dem Zentrum verschoben, Gas und Staub sind asymmetrisch verteilt und die Spiralarme sind schwach ausgeprägt. Aber diese Aufnahme, die mit dem FORS1-Instrument am Very Large Telescope der ESO gemacht wurde, zeigt: Im Falle von Messier 96 ist Unvollkommenheit Schönheit. Der Kern der Galaxie ist kompakt aber hell, die dunklen Staubbänder bewegen sich in einem filigranen Wirbel zur Mitte hin. Die Spiralarme, ungleichmäßige Ringe aus jungen blauen Sternen, wirken wie Ketten aus blauen Perlen. Messier 96 liegt im Sternbild Leo (Der Löwe) und ist die größte Galaxie in der Leo I-Galaxiengruppe. Gemessen an den äußeren Spiralarmen beträgt ihr Durchmesser etwa 100.000 Lichtjahre - das entspricht ungefähr der Größe unserer Milchstraße. Ihre eleganten "Unzulänglichkeiten" resultieren wahrscheinlich aus der gravitativen Wechselwirkung mit anderen Galaxien der Gruppe, vielleicht auch ...

17. Oktober 2011: The night sky above the 2600-metre-high Cerro Paranal in the Atacama Desert in Chile is dark and clear. So clear, that very long sequences of photos can easily be taken without a single cloud obscuring the stars as they rotate around the southern celestial pole. The site is home to ESO’s Very Large Telescope (VLT) array. Its four 8.2-metre Unit Telescopes dominate this image made by Farid Char, a student at Chile’s Universidad Católica del Norte. One of the smaller Auxiliary Telescopes is also visible, hiding in the background in the bottom left corner. But the star of the show is the striking starry sky. Made by combining 450 exposures of 20 seconds each, the image captures the apparent stellar movement during two and a half hours. This movement, signalled by dotted trails, is illusory: the Earth, and not the stars, is rotating as time goes by. The sequence has ...

10. Oktober 2011: Diese beeindruckende Luftaufnahme zeigt die ALMA Operations Support Facility (OSF), die 2900 Meter über dem Meeresspiegel in den Ausläufern der chilenischen Anden nahe San Pedro de Atacama liegt. ALMA, das Atacama Large Millimeter/submillimeter Array, befindet sich auf dem 5000 Meter hohen Chajnantor-Plateau und ist derzeit noch im Bau. Um die Strahlung des Universums im Millimeter- und Submillimeter-Bereich beobachten zu können, ist eine solch hohe Lage für das ALMA-Antennen-Anlage notwendig, jedoch bereitet der Sauerstoffmangel den am Array Operations Site (AOS) arbeitenden Menschen Probleme. Aus diesem Grund wird möglichst viel wissenschaftliche und technische Arbeit an der 2100 Meter niedriger gelegenen OSF verrichtet, von wo aus die Antennen sogar ferngesteuert werden. Im obigen Bild sind im Vordergrund von links nach rechts die nordamerikanischen, die japanischen und die europäischen Montageanlagen für die Antennen deutlich zu unterscheiden. Dort werden die Antennen von den Partnern und Auftragnehmern montiert und getestet, bevor sie an das Joint ALMA ...

3. Oktober 2011: A new Very Large Telescope (VLT) image of the Antennae Galaxies gives us what may be the second-best visible-light view yet of this striking pair of colliding galaxies with dramatically distorted shapes. This amazing object takes its name from the long antenna-like "arms" extending far out from the nuclei of the two galaxies, best seen in wider-field images by ground-based telescopes such as the one at this link. This VLT view focuses instead on the galaxies’ nuclei, where the real action is taking place as the two galaxies merge into a single giant galaxy. Spurred by shock waves created by their gravitational wrestling, the two galaxies have become dotted with brilliant blue hot young stars in star-forming regions, surrounded by glowing hydrogen gas, shown here in pink. The two pale yellow blobs are the cores of the original galaxies, shining with the light of old stars and picked out by ...

26. September 2011: When light from all four 8.2-metre Unit Telescopes of ESO’s Very Large Telescope (VLT) in Cerro Paranal on 17 March 2011 was successfully combined for the first time (ann11021), ESO Photo Ambassador Gerhard Hüdepohl was there to capture the moment. Having all four of the Unit Telescopes (UTs) working as one telescope observing the same object was a major step in the development of the VLT. While mostly used for individual observations, the UTs were always designed to be able to operate together as part of the VLT Interferometer (VLTI). All the UTs are pointed in the same direction, at the same object, although this isn’t obvious because of the wide-angle lens used to take the photo. The light collected by each of the telescopes was then combined using an instrument called PIONIER [1]. When combined, the UTs can potentially provide an image sharpness that equals that of a telescope ...

19. September 2011: This interpretation of a previous Picture of the Week was created by astronomer Alex Parker. It captures some of the essence of Paranal Observatory — a little world where astronomers leave the Earth behind and travel to the stars... metaphorically at least. The observatory lies deep in the barren Atacama Desert, which can really seem like an alien environment. It is far from civilisation and modern life, a place where visiting astronomers spend their nights gazing out at the wonders of the Universe using ESO’s flagship facility, the Very Large Telescope (VLT). The VLT is the reason why Cerro Paranal was transformed from just another mountain in the Chilean Andes into a base for world-class scientific research. When night falls over Paranal, and the night sky is aglow with stars, nebulae and nearby galaxies, the unearthly view emphasises our place in the Universe — as Alex Parker so creatively demonstrates ...

12. September 2011: Deep in the heart of the Atacama Desert, home of the Paranal Observatory, the Sun is setting at the start of another clear night. This charming photograph, taken by ESO Photo Ambassador Gianluca Lombardi shows one of four Auxiliary Telescopes (ATs) that belong to ESO’s Very Large Telescope (VLT) sitting boldly against a vivid sky of pink and blue. The full Moon, seen hovering over the horizon, has a distinctly reddish hue, a phenomenon caused by the scattering of light by Earth’s atmosphere. When the Moon is close to the horizon, the light we see from it must travel through a greater thickness of the atmosphere, so the effects of scattering are increased. As red light is more resilient to scattering than green or blue, our view of the Moon is reddened. As it happens, the reddening effect is somewhat less pronounced at sites like Paranal, as the clear air ...

5. September 2011: Am Donnerstag, dem 18. August 2011, bot der Himmel über der Allgäuer Volkssternwarte Ottobeuren einen spektakulären Anblick: zwei gleichermaßen beeindruckende und doch sehr verschiedene Phänomene erhellten die Nacht. Eines davon war ein Beispiel für modernste Technologie, das andere für die ehrfurchtgebietende Kraft der Natur. Während die ESO dort das neue Wendelstein-Laserleitsternsystem getestet hat, näherte sich eines der für diese Region typischen heftigen Sommergewitter der Sternwarte und demonstrierte eindrucksvoll, warum die Teleskope der ESO eigentlich in Chile und nicht in Deutschland stehen. Aus den dicken grauen Wolken zucken Blitze, während Martin Kornmesser – bei der ESO-Öffentlichkeitsarbeit zuständig für künstlerische Darstellungen – Zeitrafferaufnahmen des Lasertests für ESOcast 34 anfertigte. Das hier gezeigte Foto wurde zufällig genau in dem Moment aufgenommen, als ein Blitz die Szenerie erhellte. Obwohl das Gewitter noch weit entfernt war, scheint der Blitz fast wie in einem Science Fiction-Film mit dem Laserstrahl zu kollidieren. Laserleitsterne sind künstliche Sterne, die ...

29. August 2011: The first of twelve 7-metre diameter ALMA antennas has just been transported on 24 August 2011 to the 5000-metre-high Chajnantor plateau, where the Atacama Large Millimeter/submillimeter Array (ALMA) is under construction. ALMA is a giant radio telescope composed of an array of fifty 12-metre antennas, as well as a smaller array known as the Atacama Compact Array (ACA). This will have a total of four 12-metre antennas and the twelve 7-metre dishes. The four 12-metre ACA antennas have already been moved up to the high plateau, but this is the first of the smaller 7-metre dishes — which put the “compact” into Atacama Compact Array — to reach Chajnantor. It is seen in the centre of this photograph, surrounded by some of the other ALMA antennas. Penitentes ice formations are seen in the foreground.The larger 12-metre antennas of the main array cannot be placed closer than 15 metres apart as ...

22. August 2011: ALMA, the Atacama Large Millimeter/submillimeter Array, will be initially composed of 66 antennas, designed to observe the Universe in millimetre and submillimetre radiation. The main array will consist of fifty 12-metre antennas that can be spread over distances from 150 metres to 16 kilometres. In addition to the main array, ALMA will also have a compact array, composed of four 12-metre antennas plus twelve 7-metre antennas. By using the technique of interferometry, ALMA will work as a single giant telescope, enabling astronomers to observe the cold universe with unprecedented sensitivity and resolution. From the high altitudes of the Andes, ALMA will provide a revolutionary contribution to the search for our cosmic origins. ALMA, an international astronomy facility, is a partnership of Europe, North America and East Asia in cooperation with the Republic of Chile. ALMA construction and operations are led on behalf of Europe by ESO, on behalf of North ...

15. August 2011: Just as the Sun rises in the east and sets in the west, so do the stars appear to slowly march across the sky. Their leisurely pace is imperceptible to a casual observer, but you can test the effect for yourself: on the next clear night note the position of a bright star, and then check again a few hours later. The change is not caused by the motion of the stars themselves, but rather the rotation of the Earth. Long-exposure photography is the ideal way to capture this motion. A camera is set up on a tripod, and the shutter opened to the sky. Normal snapshots gather light for a fraction of a second, but these special images need starlight to pour onto them for much longer, like a bucket collecting rainwater. To obtain this image, ESO Photo Ambassador Gianluca Lombardi collected light for a total of 25 minutes. ...

8. August 2011: Der Nachthimmel über dem Cerro Paranal, der Heimat des Very Large Telescope (VLT) der ESO, ist dunkel und gesprenkelt mit den hellen Sternen der Milchstraße und auch weiter entfernten Galaxien. Dennoch sieht man den Erdboden selten in so starkem Kontrast zum Nachthimmel wie in dieser Aufnahme, die eine dünne, weiße Schneedecke zusammen mit dunkleren Flecken in der Wüstenlandschaft zeigt. Dieses Bild entstand in der letzten Woche kurz vor Sonnenaufgang und wurde von ESO-Fotobotschafter Yuri Beletsky aufgenommen, der als Astronom am La Silla-Paranal-Observatorium arbeitet. Er fing damit nicht nur die ungewöhnlich verschneite Landschaft der Atacama und die Kuppeln auf dem Gipfel des Berges ein, sondern auch einen atemberaubend schönen Nachthimmel. Links vom VLT erkennt man eine Satellitenspur, auf der rechten Seite eine helle Sternschnuppe. Der Cerro Paranal ist ein 2600 Meter hoher Berg in der chilenischen Atacamawüste. Dort ist es außergewöhnlich trocken, die Luftfeuchtigkeit liegt häufig unterhalb von 10%. Im Allgemeinen ...

1. August 2011: The hazy and aptly named Fine Ring Nebula, shown here, is an unusual planetary nebula. Planetary nebulae form when some dying stars, having expanded into a red giant phase, expel a shell of gas as they evolve into white dwarfs. Most planetary nebulae are either spherical or elliptical in shape, or bipolar (featuring two symmetric lobes of material). But the Fine Ring Nebula — captured here by the ESO Faint Object Spectrograph and Camera mounted on the New Technology Telescope at the La Silla Observatory in Chile — looks like an almost perfect circular ring. Astronomers believe that some of these more unusually shaped planetary nebulae are formed when the progenitor star is actually a binary system. The interaction between the primary star and its orbiting companion shapes the ejected material. The stellar object at the centre of the Fine Ring Nebula is indeed thought to be a binary system, ...

25. Juli 2011: This unusual 360-degree panoramic projection reveals the observing site from a fresh perspective. In the centre of the image, staff at Paranal have gathered to watch the sunset. On the right, the enclosures of the VLT’s Unit Telescopes can be seen: vast machines, each with a primary mirror 8.2 metres across and weighing 23 tonnes. Also visible are several of the smaller 1.8-metre Auxiliary Telescopes, which complement the Unit Telescopes. On the left of the picture is the control building, from where the telescopes are operated remotely during observations. No one remains inside the telescope domes after they are opened. Since first light in 1998 the Very Large Telescope has been used by ESO astronomers to study the Universe, including some of the most exotic phenomena known, such as exoplanets, supermassive black holes, and gamma-ray bursts. An amazing interactive virtual tour of Paranal is available here. Links Extended to 360x180 ...