Thomas Wright was the first person to work out that the Milky Way was a flattened disc of stars. He studied the skies from this observatory in County Durham, which my mum and dad live next to.
Articles tagged with "astronomy"
I went up onto the roof of the ESO building on a clear evening, and tried a star trail photo. I’d never done one from the city before but I thought it should be possible to do one, with the exposure set so that the buildings were not overexposed but at least some stars showed up. With a 4s exposure at ISO 100, this just about worked. So I took 500 of those and stacked them together, and got some decent trails. There was also someone coming down the trail from Alto del Naranjo to San Carlos de Apoquindo.
The Hell Itch passed. By the time I got on the flight from Houston to Santiago it seemed like an insane dream. During the night, we flew over Nicaragua, and I tried to recognise places I’d been. The Milky Way was bright, and there were thunderstorms flickering on the horizon.
It had been totally clear when I started climbing but clouding over during the morning. By the time I got to the top it was starting to rain. I was going to go to the very highest point, but there was a sign asking people not to, so I didn’t.
I was planning to walk back down again but then it started hailing. Two tourists from New York were there, they had a car and they offered me a lift down. It was a better option than three hours walking in the hail.
In this photo, you can see the glow of lava from the summit crater and also, in the distance, the glow of lava from another lava lake in Pu’u O’o crater.
I spent a lot of my time around Kilauea volcano, which has been erupting since 1983. The lava lake in the summit crater looked awesome at night, and the Milky Way overhead made the crater’s edge a pretty stunning place to be.
The moon rose a bit after midnight. I took a video when it did, and did some post processing to extract the best images from the video sequence and combine those to make this final image.
I went to Roan Jase for a night to do some astrophotography with Julien and Jorge. Conditions were really good, though pretty savagely cold in late autumn, 1000m above sea level.
Trying to get an equatorial mount aligned is tricky. It would be easy enough in the northern hemisphere, where there’s a nice bright star near the celestial pole to target, but in the south there’s no bright pole star and we struggled to get the telescope well aligned. Shining the laser through the guide scope to see where we were pointing was our best technique.
I’d noticed the geostationary satellites a couple of times before on my photographs from Paranal. With this photograph I set out to capture as many as I could and then to identify them. I got a list of all of them, and then worked out the spatial scale of my photo and which direction I was pointing, so that I could work out which point of light was which satellite.
Coffee helps me appreciate the wonders of the universe, and the wonders of the universe help me appreciate my coffee.
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.
The finest sight of the southern skies. Us poor natives of the northern hemisphere are seriously deprived, restricted to seeing some crappy outer spiral arm of the galaxy while the lucky folk of the south get to look towards the centre.
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.
São Miguel do Gostoso is not far south of the equator, and when the night sky was clear I could see a lot of stars that I don’t see from Chile. It seemed strange to me to see the Plough to the north, familiar from my native mid-northern latitudes, and at the same time in the same sky see the Southern Cross to the south.
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.
A view over the residence at Paranal, looking towards the celestial equator. I stacked 763 individual photos to make this one, each of the individual ones being a 20s exposure at ISO 800, using a 24mm lens at f/2.8.
The night after our observations, we spent one more night at La Silla before our transport back to La Serena. We were out taking photographs when the airglow became very strong, just about visible to the naked eye and very bright on a long exposure photograph. An observer from the Swiss Telescope came out to check out the skies as well.
On my second trip to La Silla, I had plenty of free time. We were observing for three nights, but the transport from La Serena to La Silla only goes three times a week, so we had to arrive three nights before our run started, and leave one night after. So, we did a lot of photography. I made this image by stacking 700 individual images, each of which was a 20s exposure at ISO 100, using a 24mm lens at f/1.4. I started the sequence about 45 minutes after sunset, so that there was still some twilight to light up the sky. The moon was full, so the telescopes and the desert got illuminated by that.
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
Star trails over two of the four telescopes which make up the VLT. To make this image I stacked 750 individual photos, each one a 20s exposure at ISO 400, using a 24mm lens at f/1.4.
Everyone’s favourite southern constellation over two of the telescopes at Paranal, with the Coalsack Nebula, the Eta Carina nebula, and the two Magellanic Clouds also visible.
UT4 is equipped with a laser. It creates an artificial star from which the way the atmosphere is moving can be measured, and then corrected for in real time by distorting the telescope mirror. It’s incredible technology which allows amazingly sharp images to be taken, and it also looks extremely cool from out on the platform.
No sunspots to be seen on the sun’s surface today, but at least a turbulent atmosphere made it go crazy shapes at sunset.
Solar activity has been unusually low recently but today there were some nice sunspots visible at sunset. I didn’t use a filter for this photograph – my very slow 400mm f/5.6 lens plus the thickness of the atmosphere between me and the sun at sunset did the job well enough.
Normally when making star trail photographs, I take lots of short exposures and stack them together. Today I tried it the old fashioned way just for a change, and did a single exposure for two and a bit hours – the battery ran out before it got to the intended three hours. The benefit of doing it this way was that geostationary satellites show up in the long exposure as bright spots along the celestial equator.
My photography set up is not very good for moon shots – I use a very old and cheap Olympus 400/5.6 lens with Canon adapter, and the lens has awful contrast and sharpness. But with some luck and some post processing, the moon still comes out OK.
The fabled green flash happens sometimes when the atmosphere refracts the sun’s light in just the right way at sunset. I watch the sunset every single night that I’m at Paranal, unless there’s something I have to be doing at that moment, and usually the sun sets with no hint of green. People on the platform usually say something about how they see it much more often at La Silla, but I didn’t see it there either.
Tonight, I didn’t see the flash by eye, but I caught it on camera nevertheless. A strip of green floated above the rest of the orange disk, too faint for me to notice it but there without any doubt.
Jupiter was at its closest approach to Earth on January 5th, so during my shift I took a photo of it each night with a 400mm lens. With that, I could see its four largest moons, Io, Europa, Ganymede and Callisto. They orbit the planet in roughly 2, 4, 8 and 16 days, so over the course of my 11 day shift I could see them all moving around the planet. I worked out which one was which using Sky and Telescope’s tool. On 15th January the Moon was very close to Jupiter, which is why the sky is murky grey on that day instead of the nice black the other times.
A view towards the residencia from the platform at Paranal. I made this photo by stacking 500 photos, each of which was a 5s exposure at ISO 3200.
Clouds on a moonlit night makes for bad observing conditions but good photography conditions. If we can’t open the telescopes, then at least I can go outside and take some shots.
A view south with airglow of different colours – red from nitrogen gas, green from oxygen, all glowing faintly in the upper atmosphere.
The VLT is the Very Large Telescope. That’s the name given to the whole facility that consists of our four telescopes each with a mirror 8.2m across. Here, you see two of them, Melipal, which I work as a support astronomer for, and Yepun, which has a cool laser. In between them is the VST, which only has a 2.5m mirror, but VST is disappointingly not actually an acronym for Very Small Telescope, but instead means VLT Survey Telescope. It is used for large surveys, such as the VPHAS+, which I’m involved in and which is taking images of the Milky Way in the light emitted by hydrogen gas. VPHAS+ is a double nested acronym – it’s the VST Photometric Hα Survey, so that would actually be the Very Large Telescope Survey Telescope Photometric Hα Survey.
Paranal does the majority of its work in service mode, where we, the observatory staff, carry out observations that have been requested and designed by other astronomers. This has the advantage that if they need certain weather conditions, then we simply wait until we have conditions as good or better than needed and take the observations then. But for the astronomers to come and carry out their own observations also has its advantages – they can see much better how the observatory works, and make sure the data is exactly as they want it. But though the weather is good here at least 90 per cent of the time, there’s still a chance that a visitor will get no data at all. That happened tonight, and it was sadder than usual because it was Christmas night. People had travelled thousands of miles to be away from friends and families, in the hope of better understanding some of the mysteries of the universe in compensation, but it was cloudy for most of the night and we couldn’t do any observing at all.