Picture of the Week

4 May 2009

The Observing Platform as the Crow Flies *

This aerial shot of ESO’s Very Large Telescope array on top of the 2600-metre-high Cerro Paranal in the Chilean Atacama Desert beautifully shows the various stations for the mobile Auxiliary Telescopes. The largest structures are the enclosures of the four 8.2-metre Unit Telescopes of the VLT. In the middle lies the VLT Interferometer (VLTI) laboratory.

Contrary to other large astronomical telescopes, the VLT was designed from the beginning with the use of interferometry as a major goal. The VLTI combines light captured by two or three 8.2-metre VLT Unit Telescopes, dramatically increasing the spatial resolution and showing fine details of a large variety of celestial objects. However, most of the time, the large telescopes are used for other research purposes. They are therefore only available for interferometric observations during a limited number of nights every year. Thus, in order to exploit the VLTI each night and to achieve the full potential of this unique setup, some other smaller, 1.8-metre dedicated telescopes were included into the overall VLT concept. These telescopes, known as the VLTI Auxiliary Telescopes (ATs), are mounted on tracks and can be placed at precisely defined “parking” observing positions on the observatory platform (seen along the lines in the image). From these positions, their light beams are fed into the VLTI laboratory via a complex system of reflecting mirrors mounted in an underground system of tunnels.

Taken in 2005, this photo shows only two of the four ATs that are currently in operation. The enclosure on the upper right of the image will soon host the VLT Survey Telescope (VST).


24 April 2009

Distorted galaxy NGC 2442

The distorted galaxy NGC 2442, also known as the Meathook Galaxy, is located some 50 million light-years away in the constellation of Volans (the Flying Fish). The galaxy is 75,000 light-years wide and features two dusty spiral arms extending from a pronounced central bar that give it a hook-like appearance, hence its nickname. The galaxy’s distorted shape is most likely the result of a close encounter with a smaller, unseen galaxy. This image is based on data acquired with the 1.5-metre Danish telescope at ESO’s La Silla Observatory in Chile, through three filters (B: 250 s, V: 187 s, R: 150 s).


20 April 2009

Lord Drayson opens JENAM 2009

Today, 20 April 2009, was the opening of the European Week of Astronomy and Space Science (JENAM 2009), which takes place at the University of Hertfordshire, UK. Lord Drayson, the British Minister of State for Science and Innovation, addressed the many attendees to this conference, expressing the importance of astronomy and space science for today’s society. He also visited the ESO stand where he was introduced to ESO’s flagship astronomical facility, the Very Large Telescope, by Tim de Zeeuw, the ESO Director General, and Patrick Roche, UK member of the ESO Council. Tim de Zeeuw also explained about the European Extremely Large Telescope, a project which the minister showed great interest for.


14 April 2009

Paranal Observatory and the Volcano Llullaillaco*

This marvellous aerial photograph of the home of ESO’s Very Large Telescope (VLT), fully demonstrates the superb quality of the observing site. In the foreground we see the Paranal Observatory, located at an altitude of 2,600 metres on mount Paranal in Chile. In the background we can see the snow-capped, 6,720 meter-high volcano Llullaillaco, located a mind-boggling 190 km further East on the Argentinean border. This image is a testimony of the magnificent quality of the air and the ideal conditions for observing at this remote site.

Clearly visible in the image are the domes of the four giant 8.2-metre Unit Telescopes of the VLT, with the Control Building, where astronomers carry out the observations, in the foreground. Taken several years ago, this photograph does not show the Auxiliary Telescopes nor the dome of the soon to come VST Survey Telescope.

#L


1 April 2009

Messier 100 and Supernova SN 2006X

Similar in appearance to our own Milky Way, Messier 100 is a grand spiral galaxy that presents an intricate structure, with a bright core and two prominent arms. The galaxy harbours numerous young and hot massive stars as well as extremely hot regions of ionised hydrogen. Two smaller arms are seen emerging from the centre and reaching towards the larger spiral arms. The galaxy, located 60 million light-years away, is slightly larger than the Milky Way, with a diameter of about 120,000 light-years. A supernova was discovered in M100 on 4 February 2006. Named SN 2006X, it is the 5th supernova to have been found in M100 since 1900. This image is based on data acquired with the 1.5 m Danish telescope at the ESO La Silla Observatory in Chile, through three filters (B: 1390 s, V: 480 s, R: 245 s). The supernova is the brighter of the two stars seen just to the lower right of the galaxy centre.


30 March 2009

The Paranal Residencia at Night

Night view of the Paranal Observatory, obtained on 21 March 2009. The Residencia — the place where staff can eat and sleep — is visible in the foreground, while one can distinguish the 8.2-metre Unit Telescopes of ESO’s Very Large Telescope in the higher background. Yepun, the Unit Telescope no. 4, is seen using the laser guide star to assist the adaptive optics instruments on the VLT. This allows astronomers to obtain images free from the blurring effect of the atmosphere, regardless of the brightness and location on the sky of the observed target. The image shows the great value of the dark night sky above Paranal. The band of the Milky Way is running through the image vertically. Orion and the Orion Nebula can be seen in the upper left corner along with a number of other interesting deep-sky objects in Auriga, the Charioteer. Tremendous efforts are being put into preventing light pollution from the Residencia and surrounding cities. Only long exposures with sensitive digital cameras are able to reveal the dim lights from the residencia rooms.


23 March 2009

The Tarantula Nebula

Located inside the Large Magellanic Cloud (LMC) – one of our closest galaxies – in what some describe as a frightening sight, the Tarantula nebula is worth looking at in detail. Also known as 30 Doradus or NGC 2070, the nebula owes its name to the arrangement of its bright patches that somewhat resemble the legs of a tarantula. Taking the name of one of the biggest spiders on Earth is very fitting in view of the gigantic proportions of this celestial nebula — it measures nearly 1,000 light years across ! Its proximity, the favourable inclination of the LMC, and the absence of intervening dust make this nebula one of the best laboratories to better understand the formation of massive stars. This spectacular nebula is energised by an exceptionally high concentration of massive stars, often referred to as super star clusters. This image is based on data acquired with the 1.5 m Danish telescope at the ESO La Silla Observatory in Chile, through three filters (B: 80 s, V: 60 s, R: 50 s).


9 March 2009

First Light for the Active Phasing Experiment — a step towards the E-ELT

The 40-metre-class primary mirror of the European Extremely Large Telescope (E-ELT) will be composed of 984 individual segments, which must be aligned with incredible precision.

The position of the individual hexagonal mirrors needs to be controlled with nanometre precision (1 nanometre is 1 millionth of a mm). This can only be achieved with the help of new technologies and a prototype component for this high-tech alignment of segmented mirrors is seen in this image.

The so-called Active Phasing Experiment achieved its First Light during the night of 6 December 2008 on the visitor focus of Melipal, one of the 8.2 m Unit Telescopes of ESO’s Very Large Telescope at Paranal. Made in collaboration with several European partners, the current active segmented mirror is composed of 61 hexagonal segments.

You can move around the experiment in this Quicktime VTR animation.


2 March 2009

The Sombrero Galaxy

One of most famous spiral galaxies is Messier 104, widely known as the "Sombrero" (the Mexican hat) because of its particular shape. It is located towards the constellation Virgo (the ‘virgin’), at a distance of about 30 million light-years and is the 104th object in the famous catalogue of deep-sky objects by French astronomer Charles Messier (1730 - 1817).

This luminous and massive galaxy has a total mass of about 800 billion suns, and is notable for its dominant nuclear bulge, composed mainly of mature stars, and its nearly edge-on disc composed of stars, gas, and dust. The complexity of this dust is apparent directly in front of the bright nucleus, but is also evident in the dark absorbing lanes throughout the disc. A large number of small, diffuse objects can be seen as a swarm in the halo of Messier 104. Most of these are globular clusters, similar to those found in our own Milky Way, but Messier 104 has a much larger number of them. This galaxy also appears to host a supermassive black hole of about 1 billion solar masses, one of the most massive black holes measured in any nearby galaxy, and 250 times larger than the black hole in the Milky Way. Despite having such a massive black hole at its centre, the galaxy is rather quiet, implying that the black hole is on a very stringent diet.

This image is based on data acquired with the 1.5 m Danish telescope at the ESO La Silla Observatory in Chile, through three filters (B: 120 s, V: 100 s, R: 100 s).


23 February 2009

Startrails over Cerro Paranal in 1987

A view of Paranal from May 1987.


16 February 2009

Cosmic Butterfly

The Bug Nebula, NGC 6302, is one of the brightest and most extreme planetary nebulae known. It is located about 4,000 light-years away, towards the Scorpius constellation (the Scorpion). The nebula is the swansong of a dying solar-like star lying at its centre. At about 250,000 degrees Celsius and smothered in a blanket of hailstones, the star itself has never been observed as it is surrounded by a dense disc of gas and dust, opaque to light. This dense disc may be the origin of the hourglass structure of the nebula.

This colour image, which nicely highlights the complex structure of the nebula, is a composite of three exposures through blue, green and red filters. It was made using the 1.5-metre Danish telescope at the ESO La Silla Observatory, Chile.


9 February 2009

Beautiful Sky over Paranal *

This image, taken an early morning two weeks ago, shows with great clarity the amazing sky over Paranal, the home of ESO’s Very Large Telescope (VLT) in Chile.

The wonderful landscape of the Milky Way hangs in all its glory above three of the four 1.8-metre VLT Auxiliary Telescopes (ATs). They observe simultaneously, using interferometry to get a vision as sharp as if they used a telescope with a diameter equal to the largest distance between the telescopes, in this case, 48 metres. Because the larger 8.2-metre Unit Telescopes of the VLT are usually used individually, the four ATs have been added to the system to make full use of the interferometric laboratory.

Facing the East, the remarkable photo shows the constellations Ophiuchus (the ‘snake-holder’), Sagittarius (the ‘archer’), Scorpius (the ‘scorpion’), and Triangulum Australe (the ‘southern triangle’). The Centre of the Milky Way is just below the centre of the image.

This image is available as a mounted image in the ESOshop.


2 February 2009

Ballet of Interacting Galaxies

The pair of galaxies NGC 1531/2, engaged in a spirited waltz, is located about 70 million light-years away towards the southern constellation Eridanus (The River). The deformed foreground spiral galaxy laced with dust lanes NGC 1532 is so close to its companion — the background galaxy with a bright core just above the centre of NGC 1532 — that it gets distorted: one of its spiral arms is warped and plumes of dust and gas are visible above its disc. The cosmic dance leads to another dramatic effect: a whole new generation of massive stars were born in NGC 1532 because of the interaction. They are visible as the purple objects in the spiral arms.

This exquisite image was made using the 1.5-metre Danish telescope at the ESO La Silla Observatory, Chile. It is based on data obtained through three different filters: B, V and R. The field of view is 12 x 12 arcmin.


26 January 2009

Cleaning a VLT mirror

The 8.2m diameter main mirror of Antu, the first Unit Telescope of ESO's Very Large Telescope, is being cleaned using carbon dioxide snow.

While the telescope enclosure is maintained extremely clean, the mirrors are exposed to the elements during the observations. Consequently, dust from the desert slowly accumulates over the surface of the mirror, making it less reflective over time.

The mirror's surface is so delicate that normal cleaners used for household mirrors are not appropriate for telescopes. Observatories have developed other methods, such as this one using carbon dioxide snow. The tiny CO2 snowflakes in the white plume have a temperature of almost minus 80 degrees Celsius; when they land on the mirror, which is at room temperature, they cause minuscule 'explosions' that detach the dust grains from the surface. The dust then floats away, leaving the mirror clean. The process is nevertheless very delicate: should Alain Gilliotte, the optician performing the cleaning, let the CO2 device touch the mirror, the fragile reflective Aluminium coating would be scratched. Also, hair or cloth lint should stay away from the mirror, which is why the optician is wearing a white suit made of special plastic. 


12 January 2009

The Trapezium Cluster

The Orion Nebula is arguably the finest of all nebulae within the Milky Way visible from the Northern Hemisphere. With a gaseous repository of 10,000 suns, and illuminated by a cluster of hot young stars, the clouds of Messier 42 — as it is also known — glow with fantastic colours and shapes, giving us a bird’s eye view of one of the greatest star forming nurseries in our part of the Milky Way. Messier 42 is a complex of glowing gas, mostly hydrogen but also helium, carbon, nitrogen, and oxygen in decreasing amounts, located 1,500 light-years away. At its very heart, we find the Trapezium, a group of four very hot stars that illuminate the nebula. They are the brightest of an extended cluster of several thousand young stars many of which lie unseen within the opaque gas and dust. Amazingly, whilst the Orion Nebula is easy to identify with the unaided eye, there is apparently no written record of its existence before the 17th century.

This image is based on data acquired with the 1.5 m Danish telescope at the ESO La Silla Observatory in Chile, through three filters (B: 60 s, V: 30 s, R: 21 s). East is at the upper right corner and North is at the lower right. 


15 December 2008

Spiral Galaxy NGC 1232

The striking, large spiral galaxy NGC 1232, and its distorted companion shaped like the greek letter "theta".

The pair is located roughly 70 million light-years away in the constellation Eridanus (The River). Billions of stars and dark dust are caught up in this beautiful gravitational swirl. The blue spiral arms with their many young stars and star-forming regions make a striking contrast with the yellow-reddish core of older stars.

This image is based on data acquired with the 1.5 m Danish telescope at the ESO La Silla Observatory in Chile, through three filters (B: 900 s, V: 400 s, R: 400 s). East is up, North is to the left.


8 December 2008

ESO helps school to get a bus

About a year ago, ESO kindly agreed to donate a surplus van to the Colegio Hellen Keller, a school for children with visual disabilities, located in Santiago, Chile. The school was in desperate need of some form of transport as there were many children who could either not attend school at all, or had to spend the weekdays away from their family, simply because they could not make the daily journey on public transport, due to their disabilities. The initial idea was to donate one of the bus used to carry staff to Paranal. However, it became clear that this big van was not ideal for the school, especially with rising fuel prices. ESO kindly offered to donate the proceeds from the sale of the van instead, which was in excess of 4.000.000 Chilean Pesos (about 5,000 EUR). The school set up a fund to raise the rest of the money needed to purchase a brand new bus and recently took delivery after a lot of hard work from many fundraisers. As you can see from attached photo, the kids were delighted!


1 December 2008

SN2008bk: The last moments of a star

Supernova 2008bk in the spiral galaxy NGC 7793 was discovered at the end of March 2008 by amateur astronomer Berto Monard from South Africa. The galaxy is 13 million light-years away in the direction of Sculptor constellation. This supernova is a typical example of a massive star that exploded at the end of its life. But this time, the astronomers were able not only to see the explosion, but to precisely pinpoint the star that exploded, a rather rare achievement.

This was made possible because the explosion site had been observed several times with the help of ESO's Very Large Telescope, the latest images having been observed only a few months before the explosion with the new HAWK-I instrument.

An European team of astronomers, led by Seppo Mattila of University of Turku, Finland, then observed the explosion site again two months after the supernova's discovery, this time with the VLT's NACO instrument, which uses adaptive optics to resolve the finest details. Adaptive optics is a technique that allows astronomers to overcome the blurring effect of the atmosphere, thereby producing very sharp images. By comparing these sets of images, the team found the doomed star from the early images.

The colours and brightness of the star revealed it to belong to the family of red supergiants — to which the very bright star Betelgeuse also belongs — and that it had initially a mass of about eight to nine times the mass of our Sun.

Just before exploding, it was about 500 times larger than our Sun, meaning that if it were placed where the Sun is, it would engulf all the planets up to the planet Mars.

This is only the fifth time astronomers have been able to directly trace back the star that exploded as a supernova. Of all these red supergiants, four of them have about eight times the mass of our Sun, which is thought to be the minimum mass needed to produce such explosions.

This research appears today in print as a Letter to the Editor of the Astrophysical Journal (ApJ, 2008, vol. 688, L91). The team is composed of S. Mattila (Tuorla Observatory, University of Turku, Finland), S. Smartt and Mark Crockett (Queen's University Belfast, UK), J. Eldridge (University of Cambridge, UK), J. Maund (University of Copenhagen, Denmark), and J. Danziger (Universita di Trieste, Italy). 

The image shows the star before it exploded (left), as observed with ISAAC and FORS on ESO's Very Large Telescope, and after the explosion (right), as seen by the very sharp NACO.


25 November 2008

Sunset over Paranal Panorama *

Le Very Large Telescope (VLT) on the 2600-metre-high Cerro Paranal is ESOs premier site for observations in the visible and infrared light. It is located in the Chilean Atacama desert. All four unit telescopes of 8.2-metre diameter are individually in operation with a large collection of instruments and have already made amazing scientific discoveries.

The VLT offers also the possibility of combining coherently the light from the four UTs to work as an interferometer. The Very Large Telescope Interferometer (VLTI), with its own suite of instruments, ultimately providing imagery at the milli-arcsecond level as well as astrometry at 10 micro-arcsecond precision. In addition to the 8.2-metre diameter telescopes, the VLTI is complemented with four Auxiliary Telescopes (AT) of 1.8-metre diameter to improve its imaging capabilities and enable full nighttime use on a year-round basis.

The enclosure of the yet to come VLT Survey Telescope (2.6-metre diameter) is visible in the centre of the panorama.


11 November 2008

The Carina Nebula

The Carina Nebula is a large bright nebula that surrounds several clusters of stars. It contains two of the most massive and luminous stars in our Milky Way galaxy, Eta Carinae and HD 93129A. Located 7500 light years away, the nebula itself spans some 260 light years across, about 7 times the size of the Orion Nebula, and is shown in all its glory in this mosaic. It is based on images collected with the 1.5-m Danish telescope at ESO's La Silla Observatory.

Being brighter than one million Suns, Eta Carinae (the brightest star in this image) is the most luminous star known in the Galaxy, and has most likely a mass over 100 times that of the Sun. It is the closest example of a luminous blue variable, the last phase in the life of a very massive star before it explodes in a fiery supernova. Eta Carinae is surrounded by an expanding bipolar cloud of dust and gas known as the Homunculus ('little man' in Latin), which astronomers believe was expelled from the star during a great outburst seen in 1843.


« Previous 1 | ... | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 Next »
Showing 281 to 300 of 328
Bookmark and Share

Also see our