Ugens billede 2012

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potw1213-da — Ugens billede
Ville du ønske, du var her?
26. marts 2012: Den franske fotograf Serge Brunier – en af ESO’s fotoambassadører – har skabt dette sammenhængende 360-graders panorama af Chajnantor-plateauet i Atacama-ørkenen, hvor Atacama Large Millimeter/submillimeter Array (ALMA) er under opførelse. Panoramaprojektionen har forvrænget ALMA-antennernes form en smule, men det giver stadig en fornemmelse af, hvordan det ville være at stå midt i dette imponerende nye observatorium. Panoramaet viser også Chajnantor-plateauets fuldstændige isolation; i en højde af 5000 meter er der næsten ingen former i landskabet bortset fra nogle få bjerg- og bakketoppe. Selvom det er udfordrende at konstruere et så ambitiøst teleskopprojekt i et afsidesliggende og barskt miljø, er den højde beliggenhed perfekt til submillimeter-astronomi. Det skyldes, at vanddamp i atmosfæren normalt absorberer denne form for stråling, men på højtliggende steder såsom Chajnantor, er luften meget tørrere. ALMA lavede sine første videnskabelige observationer den 30. september 2011 med en mindre gruppe af antenner. Når observatoriet er færdigt, vil det imponerende ...
potw1212-da — Ugens billede
VLT går på løvejagt
19. marts 2012: Very Large Telescope har fanget endnu et medlem af Leo I-galaksegruppen i stjernebilledet Leo (Løven). Galaksen Messier 95 ses direkte ind mod dens skive af stjerner, gas og støv og fremviser derfor meget tydeligt sin spiralstruktur. Spiralarmene danner en næsten perfekt cirkel rundt om galaksens centrum, før de spredes ud og skaber en mankelignende effekt, som enhver løve ville være stolt af. Et andet, men måske endnu mere slående træk ved Messier 95, er dens flammende gyldne kerne. Den indeholder en stjernedannende ring, som er næsten 2000 lysår på tværs, og her foregår en stor del af galaksens stjernedannelse. Dette fænomen forekommer oftest i bjælkespiralgalakser som Messier 95 og vores eget hjem, Mælkevejen. I Leo I-gruppen står Messier 95 i skyggen af sin bror Messier 96 (se potw1143). Messier 96 er faktisk det mest lysstærke medlem af gruppen og – som ”den stolte leder” – ligger den også navn til ...
potw1211-da — Ugens billede
Snedrys i Atacama-ørkenen
12. marts 2012: Kuplerne på ESO’s Very Large Telescope står på toppen af Cerro Paranal og bader sig i sollyset på endnu en herlig skyfri dag. Men noget er anderledes på dette billede: et fint lag af sne har lagt sig henover ørkenlandskabet. Det er ikke noget man ser hver dag, faktisk tværtimod, da Atacama-ørkenen næsten ingen nedbør får. Adskillige faktorer bidrager til de tørre forhold i Atacama. Andesbjergene blokerer for regn fra øst, og den chilenske kyststrækning fra vest. Den kolde Humboldt-strøm ud for kysten i Stillehavet skaber et kystnært inversionslag af koldt luft, som forhindrer regnskyer i at udvikle sig. Et højtryksområde i den sydøstlige del af Stillehavet skaber cirkulerende vinde, der danner en anticyclon, som også hjælper med at holde klimaet i Atacama tørt. Takket være alle disse faktorer, er området bredt anerkendt som det tørreste sted på Jorden! På Paranal er nedbørsniveauet normalt kun nogle få millimeter om året ...
potw1210 — Ugens billede
A Window to the Past — La Silla’s transformation through time
5. marts 2012: ESO turns fifty this year, and to celebrate this important anniversary, we are showing you glimpses into our history. Once a month during 2012, a special “Then and Now” comparison Picture of the Week shows how things have changed over the decades at the La Silla and Paranal observatory sites, the ESO offices in Santiago de Chile, and the Headquarters in Garching bei München, Germany. Here are two photographs of La Silla, taken in June 1968 and the present day from near the observatory’s water tanks, looking over the rest of the site. You can examine the changes with our mouseover image comparison. In the historical image, the provisional residential area is visible in the foreground. The three telescopes in the background are, from left to right, the Grand Prism Objectif (GPO, first light in 1968), the ESO 1-metre telescope (first light in 1966), and the ESO 1.5-metre telescope (first ...
potw1209 — Ugens billede
Spinning into Action
27. februar 2012: The dynamism of ESO's Very Large Telescope in operation is wonderfully encapsulated in this unusual photograph, taken just after sunset at the moment Unit Telescope 1 starts work. An extended exposure time of 26 seconds has allowed ESO Photo Ambassador Gerhard Hüdepohl to record the movement of the dome, looking out through the opening from within, as the system swings into action. The rotating walls of the dome look like an ethereal swirl through which a slice of the Atacama Desert can be glimpsed, while the crisp dusk sky provides a splash of cool blue. The telescope structure, seen stationary in the centre of the image, houses a mirror 8.2 metres in diameter, designed to collect light from the far reaches of our Universe. The dome itself is also an engineering marvel, moving with extreme precision and allowing for careful temperature control lest warm air currents disrupt observations. Links ESO ...
potw1208 — Ugens billede
Boldly going up Cerro Paranal
20. februar 2012: ESO’s Paranal Observatory facilities, such as the Residencia, give people who work at the site a welcome shelter from the surrounding inhospitable environment. In spite of that, they also offer interesting options for those who wish to enjoy the stark and silent beauty of the Atacama Desert. See this stunning panorama! Among these is the Star Track, a walking path which connects the Residencia with the Very Large Telescope (VLT) platform, on the 2600-metre summit of Cerro Paranal. Built in 2001, the Star Track covers about two kilometres in distance and a difference in height of 200 metres. The last part of the track snakes around the west side of the mountain, offering incomparable views. This 360 degree panoramic picture is centred facing north, so the right and left edges of the picture correspond to the south. To the north, the VLT control room and part of one of the ...
potw1207 — Ugens billede
The Heart of the Milky Way, for Valentine’s Day
13. februar 2012: There is a lot to love about astronomy, and — in time for Valentine's Day — photographer Julien Girard offers a "heartfelt” example in this image. A bright pink symbol of love appears to float ethereally against the backdrop of the night sky over ESO's Paranal Observatory in northern Chile. Girard drew the heart in the air by shining a tiny flashlight keychain at the camera during a 25-second exposure with a tripod. The central region of the Milky Way appears in the middle of the heart, as the plane of our galaxy stretches across the image. The stars of the constellation of Corona Australis (The Southern Crown) form a glittering arc of jewels at the top of the heart's left lobe. The diffuse glow to the left of the heart's lowest point is zodiacal light, caused by the scattering of light from the Sun by dust particles in the ...
potw1206 — Ugens billede
A Drive Through Time — How telescopes, and cars, have changed at La Silla
6. februar 2012: ESO turns fifty this year, and to celebrate this important anniversary, we are showing you glimpses into its history. Once a month during 2012, a special “Then and Now” comparison Picture of the Week shows how things have changed over the decades at the La Silla and Paranal observatory sites, the ESO offices in Santiago de Chile, and the Headquarters in Garching bei München, Germany. These two photographs show the La Silla Observatory in the late 1960s and the present day. You can also examine the differences between the two photographs with our mouseover comparison. The telescopes aren’t the only things that have changed; the cars in the photos also show the passing of time. The Volkswagen 1600 Variant in the first picture has been replaced in the second picture by a Suzuki 4WD. Nowadays, all ESO vehicles on La Silla are white, to improve visibility at night. Standing alone ...
potw1205 — Ugens billede
A Shadow at Sunrise
30. januar 2012: In this photograph, taken by ESO Photo Ambassador Gianluca Lombardi, the Sun is rising and bathing the Chilean Atacama Desert in a familiar soft reddish glow. But this image, from 13 July 2011, has also captured something out of the ordinary: a dark shadow lurking on the horizon. Gianluca took this photograph from Cerro Armazones, looking west. Armazones is the future home of the world’s biggest eye on the sky: the upcoming European Extremely Large Telescope (E-ELT). The Sun rose behind Gianluca in just the right place to cast a daunting shadow of the 3060-metre-high mountain onto the Earth’s atmosphere in the distance. The shadow can be seen reaching over the vast desert landscape, and up across the horizon on the left side of the image. The bright summit visible on the right of the image is Cerro Paranal, at an altitude of 2600 metres. It is only 20 kilometres ...
potw1204 — Ugens billede
Barred Spiral Galaxy Swirls in the Night Sky
23. januar 2012: This image shows the swirling shape of galaxy NGC 2217, in the constellation of Canis Major (The Great Dog). In the central region of the galaxy is a distinctive bar of stars within an oval ring. Further out, a set of tightly wound spiral arms almost form a circular ring around the galaxy. NGC 2217 is therefore classified as a barred spiral galaxy, and its circular appearance indicates that we see it nearly face-on. The outer spiral arms have a bluish colour, indicating the presence of hot, luminous, young stars, born out of clouds of interstellar gas. The central bulge and bar are yellower in appearance, due to the presence of older stars. Dark streaks can also be seen in places against the galaxy’s arms and central bulge, where lanes of cosmic dust block out some of the starlight. The majority of spiral galaxies in the local Universe — including ...
potw1203 — Ugens billede
ALMA’s Grand Antennas
16. januar 2012: Workers on the Atacama Large Millimeter/submillimeter Array (ALMA) project stand next to three of the telescope’s antennas. This photograph gives a real sense of the scale of the giant dishes, whose 12-metre diameters are about seven times the average human height. When completed, ALMA will consist of 66 high-precision antennas, 54 of them with 12-metre dishes as seen in this image, and 12 more compact ones with diameters of 7 metres. The yellow 28-wheel transporter vehicle, which has to be powerful enough to carry the 100-tonne antennas, is built on a similarly giant scale. This photograph was taken at the 2900-metre-high ALMA Operations Support Facility in the foothills of the Chilean Andes, where the antennas are assembled and tested. On the left is one of the European ALMA antennas, pointing at the horizon. Behind it is one of the antennas provided to the project by Japan, while on the right, ...
potw1202 — Ugens billede
Mapping Dark Matter in Galaxies
9. januar 2012: The picture is part of the COMBO-17 survey (Classifying Objects by Medium-Band Observations in 17 Filters), a project dedicated to recording detailed images of small patches of the sky through filters of 17 different colours. The area covered in this image is only about the size of the full Moon, but thousands of galaxies can be identified just within this small region. The image was taken with an exposure time of almost seven hours, which allowed the camera to capture the light from very faint and distant objects, as well as those that are closer to us. Galaxies with clear and regular structures, such as the spiral specimen viewed edge-on near the upper left corner, are only up to a few billion light-years away. The fainter, fuzzier objects are so far away that it has taken nine or ten billion years for their light to reach us. The COMBO-17 survey ...
potw1201 — Ugens billede
A Glimpse into the Past — Then and Now at La Silla Observatory
3. januar 2012: ESO turns 50 this year, and to celebrate this important anniversary, we will be showing you glimpses into our history. Once a month throughout 2012, a special “then and now” comparison Picture of the Week will show how things have changed over the decades at the La Silla and Paranal observatory sites, the ESO offices in Santiago de Chile, and the Headquarters in Garching bei München, Germany. Our first stop on this journey through time is at La Silla, the first of ESO’s observatory sites. The historical image was taken in the late 1960s or early 1970s from the dome of the ESO 1.52-metre telescope, which had its first light in 1968. A second photograph, taken in the present day, shows how much the observatory has changed over the decades. You can examine the changes with our mouseover image comparison. In the historical image, we can see the ESO 1-metre telescope ...
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