Tuesday 17 July 2012

Observatorio del Pangue

What a fantastic stargazing experience I had at Observatorio del Pangue on Monday evening. I had been in touch with Eric, who runs the observatory, since before I left the UK. Eric is a French astronomer, who, as it turns out, worked at the Royal Observatory Edinburgh for two years, back in the 90s. He and Christian, an astrophotographer from Vicuna, take small groups up to their small observatory approximately 16 km from Vicuna. The road there is mostly a dirt track, through amazing semi-desert landscape - lots of cacti!

There were 5 of us in total this evening - me and a Chilean family of 4. At the observatory, they have a 16 inch motorised Meade telescope, and of course, fantastic dark skies.

I've decided that for this blog post, I'm going to go through every amazing object I got to see...

Alpha Centauri

We started with one of our closest neighbouring stars, Alpha Centauri, just 4.37 light-years from the Sun. It is the brightest star in the constellation of Centaurus and the 3rd brightest star in the whole sky. But, it is not just one star, Alpha Centauri is actually a binary star system - designated Alpha Centauri AB. When you look through the telescope at this system, it looks a bit like a pair of headlights coming towards you! Research shows that actually many stars are binary star systems, or indeed multiple star systems.

Omega Centauri

Credit ESO
After Alpha Centauri we moved to another object in the constellation of Centaurus - Omega Centauri. I had seen this for the first time at Observatorio Mamalluca earlier in my trip and had been blown away by it.

It's quite astonishing to think that Edmund Halley first observed this back in 1677! But it wasn't until the 1800's that John Herschel (not the astronomer who discovered Uranus) correctly recognised it as a globular cluster.

Omega Centauri is about 15,800 light-years from Earth and contains several million stars - a huge cluster. It is of particular interest to astronomers because it is so different from other galactic globular clusters.

Carbon Star

Next, we moved onto something which I really wasn't familiar with at all - a carbon star near the Southern Cross. It was quite difficult to see with the telescope as it's not very bright and there was another bright star in the field of view, but once I had it, it was amazing - such an intense red colour.

Carbon stars are ones which are similar to red giants, and very close to the end of their life. Their atmosphere contains more carbon that oxygen, leading to the combination of the two elements to form carbon monoxide. This leaves carbon atoms free to form other carbon molecules, and leads to the striking red colour.

Swan Nebula

Credit ESO
The Swan Nebula forms part of the Omega Nebula, in the constellation of Sagittarius, between 5000 - 6000 light-years away.

The Omega Nebula itself is around 15 light-years in diameter but the cloud of interstellar matter of which it is a part spans some 40 light-years!

The Sagittarius Arm of our galaxy, where this nebula is, contains a large concentration of nebulae - in other words, is a large star formation region.

I can't honestly say I saw the swan shape of the nebula, but it was beautiful to see.

Jewel Box Cluster

Credit ESO
Next, we moved on to another type of cluster - an open cluster - called the Jewel Box cluster. This was one I had seen at Mamalluca and in San Pedro.

An open cluster is one where the stars have all been born out of the same nebula - like the Pleiades which we see well in the northern Hemisphere.

The Jewel Box is particularly pretty as it has 3 brightly coloured stars, including Kappa Crucis which is bright orange and so contrasts with its bluer neighbours.

It is estimated that the Jewel Box cluster is around 14 million years old - very young compared to the Pleiades at 65 million years old!

47 Tucanae Cluster

Credit ESO
Sticking with clusters, but going back to globular, I got the chance to see the 47 Tucanae cluster.

47 Tucanae is slightly further away than Omega Centauri, around 16,700 light-years away, but almost as bright. It too is made up from millions of stars.

Globular clusters are fairly common in galaxies - our own Milky Way has around 150. They are generally contain many more stars than open clusters, and are older.

Eric said he finds it difficult to choose which of Omega and Tucanae he prefers to observe, and I quite agree. They're both beautiful to look at.

Carina Nebula

Credit ESO
The Carina Nebula is really stunning to look at and is another of the star formation regions in the Sagittarius arm of our Galaxy. The nebula is between 6500 - 10000 light-years from Earth. It is one of the largest diffuse nebulae in the skies, 4 times bigger than the Orion Nebula!

It surrounds various open clusters of stars, and one bright star of particular interest is Eta Carinae - one of the most massive and luminous in our Galaxy.

Eta Carinae. Credit Hubble
Eta Carinae is so interesting because around it is a strange mini-nebula, which is thought to have been caused by an eruption of the star in the 1800's. Christian changed the eye-piece on the telescope to a higher magnification, so we could see this feature.

The star looked a bit like it had Mickey Mouse ears on it, one slightly larger than the other! It was amazing to see this 'broken' star, which really, isn't there any more. I saw something which doesn't exist any more!

Tarantula Nebula

Credit ESO
Something I had been really pleased to see here in the Southern Hemisphere are the Magellanic Clouds. Although I have been in the Southern Hemisphere before, that was before I worked in astronomy. I was always interested in astronomy, but I didn't know to look out for these members of our local group.

So, as I knew this would probably be my last opportunity to see them, I asked if we could observe one of them with the telescope. Eric and Christian obliged to my delight, and focussed the telescope on the Tarantula Nebula, within the Large Magellanic Cloud.

I mentioned this nebula in a previous post as my friend and colleague's research area is super-massive stars and the Tarantula Nebula has some of these, and some which are acting quite strange.

With this nebula, I could definitely see where it gets its name!

Sombrero Galaxy

Credit ESO
I also got another chance to see the Sombrero Galaxy, which I had seen in San Pedro. This time it was better though, as the telescope was larger, so I could really see the shape. In San Pedro it was more of a smudge and quite difficult to distinguish.

28 million light-years from us, it's just amazing that we can see something at this distance with just a 16" telescope!

The Sombrero Galaxy gets its name from the unusually bright nucleus and the dark prominent dust line.

Planetary Nebula

Credit Hubble
We also got to see a planetary nebula - a dying star. The one we looked at is nicknamed 'The Ghost of Jupiter' as when it was first observed, it was thought to be a planet.

A planetary nebula is a late stage in the life of certain types of stars. William Herschel (the one who discovered Uranus) came up with the term, because he thought this type of nebula looked like the planet Uranus through the telescope. Although the nebula has nothing to do with planet formation, the name has stuck.

With the telescope, it looks like a diffuse oval of light - not as pronounced as a planet, much hazier.

Centaurus A

Credit ESO
We also got to see Centaurus A - a collision of galaxies.

At roughly 10 - 16 million light-years distance, Centaurus A is one of the closest radio galaxies and as such has been studied extensively. Studies show that the Sombrero Galaxy is undoing an intensified rate of star formation - something which regularly occurs due to galaxy collisions.

You can clearly see in the telescope, a black bar (dust) going across the brighter object (a spiral galaxy face on) behind.


Saturn, taken with my camera through telescope
To finish the official part of the public event, we saw Saturn. This was by far the best view I've ever had of Saturn and I could even see 5 of its moons, including Titan and Enceladus.

I asked Christian if my camera would be able to capture the image of Saturn through the eye piece of the telescope, and with a bit of fiddling with settings, he was able to get this image.

He also took a couple of video clips of it which are also very cool.

I'm quite pleased that you can even see a little colour in the image too!

I stayed a little later with Eric and Christian after the family had left and played around with my camera trying to get some more good shots of the Galactic centre and even trying to get the Magellanic Clouds. I'm quite pleased with the results I got, which you can see on my flickr account

Whilst I was playing around with my camera, Eric and Christian were doing some more serious work. 3 nights earlier, they had taken a picture of the night sky, towards the Galactic Centre. This evening, they were going to take the same shot again, with the purpose of getting an image of Pluto. They would be comparing the two photos to look for the object which had moved.

It was really exciting to be there and seeing the comparison, especially when they found it! What a fantastic way to finish off my stargazing experience in the Southern Hemisphere - to be able to say I saw an image of Pluto as taken with a 16" telescope!

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