The Stars of the Atacama

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The Stars of the Atacama

Post  Harry Hamill on Sat Sep 10, 2016 11:11 am

It’s been on the bucket list for a while.

For many years I have tried to get a decent view of the Milky Way in the Scorpius Sagittariusc region. It’s the brightest part. You’re looking towards the centre of the Galaxy. There’s a dark band running along it which is gas and dust blocking out the stars behind it.

The trouble is that from Britain or similar latitudes it is very low in the sky. You need a clear horizon to see it. But that’s not the worst if it, light pollution is the killer. It is nearly ubiquitous in Britain nowadays. You need a really dark sky. And that is like asking for a live dodo. Dark skies in the modern civilised world are extinct.

That’s why we went down to Lake Tekapo in New Zealand a few years back. There, one hundred and forty miles from Christchurch and in an area where street lighting is carefully governed, the skies are as truly dark. From Mount John we had a wonderful view of the summer sky. A memorable experience if ever there was one.

That is to say the Southern summer. It was winter back home. Many magnificent sights were on display, the Southern Cross, the Magellanic Clouds, eta Carinae and the Milky Way of the Southern Summer sky but not the celebrated a Star Clouds of Sagittarius. That was where the sun was at that time. Back home it would be low in the winter sky.

What was required was a trip during the Northern summer to somewhere far to the South. That’s where Chile and the Atacama desert came in. We took a place in Coyo, a tiny oasis settlement a few miles away from the touristry of San Pedro de Atacama. Conditions here are idyllic for the stargazer. Very dark skies which are clear most nights. Coyo sits virtually on the Tropic of Capricorn at nearly eight thousand feet. Perfick.

I did not take any equipment other than a pair of 10 x 50 binoculars. Telescopic images are a’plenty online. I just wanted to see the sky at first hand.

The Milky Way is unbelievable here. On the first night at Coyo we went out to take a look as soon as it was properly dark. Even without any time to accommodate to the darkness the brightness of the Milky Way was apparent. As our night vision developed the view became stunning. It was difficult to believe what we were seeing. A soft bright glow across the entire sky blossoming into big billowing clouds of light in the Sagittarius-Scorpius region. Billows or pillows, take your pick, the effect was three dimensional. Through binoculars the whole region a vista of clusters, nebulae and brilliant groups of stars. Completely mesmerising.

At home I have to use binoculars to find objects such as M11, M17 or M8 (The Lagoon). M22 or M4 are very difficult to find in the light pollution of the southern part of the sky. Here all of these objects are clearly visible to the naked eye. The Lagoon and the Triffid are brightly glowing embers. The Eagle and Omega fainter but clearly visible.

These are all familiar if hard to see objects for me. But then there were the unfamiliar ones. M7 behind the Scorpion’s tail is a strikingly brilliant patch of light. In binoculars it is a riot of bright stars. The Butterfly, M6 is not far away, another sparkling cluster. I could quickly pick out the constellation of Ara from our Kiwi days. It’s faint companion Norma is another area of rich star fields. Once again Cauldwell objects 82 and 89 are both naked eye objects. The Magellanic Clouds are on show, of course and The Big Two globular clusters, Omega Centauri and 47 Tucanae are superb objects in binoculars.

On another night I went out for a couple of hours quite early and concentrated on the area around the Southern Cross. It’s on the opposite side of the pole to its position when we were in NZ in the evenings and sets around midnight. I still have to get used to stars going round the pole clockwise. Eta Carinae is striking of course. Still waiting for it to go supernova. Close by are C91 and the Southern Pleiades, C102. Not really serious rivals to their northern namesake but very pretty nonetheless. Around the cross are the Running Chicken and the Pearl. Kappa Crucis the jewel box is another one I’ve met before.

The Coal Sack is striking too. The brightness of the surrounding Milky Way show it up well. I have seen a number of meteors as you tend to do if you look at the sky for any length of time. They too are seen more brightly. A couple of them were quite brilliant and one left a trail for a couple of seconds. We have also seen the Zodiacal light regularly in the evenings. I noticed it the third night we were here. You would take it for light pollution except for the high conical shape extending through Virgo and Libra. And of course there is nothing in the way of habitation for more than sixty miles North West of  Coyo.

Getting up just before dawn gives a completely different view of the sky. The Milky Way which dominates the evening sky has sunk below the horizon in the west. In the east the (northern) winter section of the Milky Way is rising. Sirius and Canopus , the brightest and second brightest stars in the sky make a brilliant pair. Orion and the bull are upside down in the northern sky, that takes some getting used to. Capella is nearing its highest point which is still quite low in the north. Fomalhaut, which we glimpse low in the autumn sky below the Square of Pegasus has passed almost overhead and is setting in the west with the southern aviary of Pavo, Tucana, Grus and Phoenix to the south. As the sky brightens Castor and Pollux rise above Licancabur, the huge volcano to the east of us.

Some other things which struck me about the sky. Scorpius seen in its entirety is a beautiful constellation, a great sweep of bright stars curling across the glowing clouds of the Milky Way. Mars and Saturn enhance it at the moment. M7 and Cauldwell 76 are beautiful additions to it. Eridanus is also much better seen in the round. Not as striking as some but it is a delicate jewelled chain meandering down into the Southern sky ending at the bright star Achernar. Corona Australis could hammer Corona Australis any time in a fight. Seen from here the teapot of Sagittarius looks more like a kettle on the boil. The star clouds are clouds of steam from the spout. The Lagoon and the Triffid an isolated whips of steam. Modest Sagitta has a bright brash Southern reflection formed by λυκι of Scorpius.

Other scraps of observation, M10 and M12 Ophiuchi are globulars I don’t remember looking at before. Zubenelgenubi, (don’t you just love that name?) otherwise α Librae, is a double star. I had completely forgotten that. Uranus and Neptune are both sussed. Uranus is the nose of a rocket shape just below ζ Pisci, Neptune is in an arrow around λ Aquarii, the right flight. Invert if you’re up North.

We have now left Atacama, but the memory of its night sky stays with us. Totally magnificent. Totally unforgettable.

Harry Hamill

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