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Articles tagged with "paranal"
A half hour exposure reveals a string of stationary lights over Paranal, strung out roughly along the celestial equator. They are all geostationary satellites, orbiting at an altitude of 36,000 km where it takes exactly 24 hours to orbit the Earth.
The Next Generation Transit Survey is being commissioned at Paranal. It will consists of 12 small telescopes, all operating remotely to search for planets around other stars. I went over there to take some photos as they were preparing for their official first light.
It’s very dark at Paranal but there’s still background light that we can’t do anything about: the atmosphere itself glows at night. It can be surprisingly bright. Often it’s green, when oxygen atoms are glowing. It can be red, too, when nitrogen is responsible. And it can be orange, when sodium atoms are being excited. Tonight, it was extremely orange, looking a lot like streetlights on clouds, except there were no clouds, and there are definitely no streetlights near here. It got really strong while I was taking a time lapse and you can see huge waves in the upper atmosphere rippling.
The Milky Way is at the right, and the Milky Way’s two satellite galaxies, the Magellanic Clouds, are in the middle of this photograph. There was a lot of airglow to the south west, and just to the right of the Large Magellanic Cloud you can see the distant glow from the town of Taltal.
The beautiful southern Milky Way, shining brightly over the four telescopes of the VLT, and the VST in the distance.
The Milky Way crosses the sky over two of the Auxiliary Telescopes. The sky looked pretty dark to the naked eye but in the long exposure it turned out to be full of strong red airglow. Around sunset, there are usually lots of satellites visible crossing the sky, and a few can be seen in this photo.
In the late evening twilight just before the start of proper darkness, the centre of the galaxy rises behind UT4.
The centre of the galaxy passes right over Paranal. We take great care to avoid stray light that could affect our observations, but this photo contains damning evidence – someone left the lights on in the VLTI control room.
Paranal is very dark, but there are some sources of light pollution we can’t do anything about. 80 miles north is the city of Antofagasta, which showed up more clearly than usual in this photo because of low cloud reflecting the street lights. And a similar distance up is the upper atmosphere, which glows faintly at night. Further afield, dust particles in the solar system reflect sunlight and cause the faint white band that stretches up from the horizon. The handle of the Plough is visible just above Antofagasta – a far northern constellation that we can just about see from down here.
The centre of the Milky Way is rising next to UT4 in this photo, with Alpha and Beta Centauri and the Southern Cross high over the VLTI control room, inside which an insanely complicated system of mirrors and lenses can combine the light from four telescopes to study objects in incredible detail.
A view from out the back of the residencia, where you can see the southern stars trailing to the right, and the northern stars trailing to the left.
The Magellanic Clouds are satellite galaxies of the Milky Way. Mapuche mythology says that today there is a large one and a small one, but there used to be three large ones. One disappeared, one is on the way out, and the third one is still complete for now, but when it too runs out, the universe will end.
Just after sunset, you can usually see a dark band above the horizon with a red band of colour above it. This is the shadow of the Earth on the atmosphere, with the last of the daylight scattering off the dust in the air higher up. It’s sometimes called the Belt of Venus.
Spotting Hubble going over is always nice. It’s not so easy to see – you can’t miss the International Space Station when it goes over, but Hubble is much smaller and fainter. It also orbits a bit lower so it’s often crossing the sky in twilight. Tonight, though, it was already quite dark when I caught it going over UT3