Southern stargazing

On Sunday night I found myself next to the beautiful, blue, glacier-fed waters of Lake Tekapo. If you've been following my travels you may remember that I was here a week or two ago visiting the Mt John Observatory. Being such a beautiful clear evening I decided to have a walk up the Department of Conservation (DOC) path to observe the stars from the summit (note: a red torch is essential for coming back down if you ever find yourself doing this).

By about half an hour to an hour after sunset, there were thousands of stars visible. It was fantastic. I easily found the 'Pointers' over the southern horizon and used them, along with the Southern Cross, to find the point directly above the south pole. On the other side of the pole I could easily make out the Large and Small Magellanic Clouds. These two dwarf galaxies are orbiting our galaxy - the Milky Way - and are being slowly consumed. Back across the pole I noticed that the dust cloud next to the Southern Cross was really inky black. The contrast between it and the starlight from the Milky Way was brilliant.

I followed the Milky Way across the sky to Orion who was standing on his head. A short hop down towards the horizon took me to the Hyades (and Aldebaran) and to the Pleiades (Seven Sisters/Subaru) which were a matter of degrees above the horizon. It was amazing to see the Milky Way to within five or so degrees above the horizon. Back in Manchester you can't see any of it because we have too much light pollution and the air isn't too transparent.

For the next hour or two I sat and watched the area around the south pole. It is just so darn interesting and I never get to see it from up in the UK. It was stunning. I also spotted four meteors between the Pointers, Southern Cross, LMC and SMC. They may have been sporadic (random directions), but it almost seemed as though they were coming from the same radiant. That is most likely wishful thinking on my part.

Southern stargazing. Sweet as.

Posted in astro blog by Stuart on Tuesday 21st Feb 2006 (04:04 UTC) | Permalink

Mahutonga

According to Mauri tradition, at the beginning of October 950 AD, Polynesian explorers first discovered the southern part of New Zealand. To travel so far south into the wide blue Pacific Ocean they had used the stars and other natural cues such as migrating birds, fish and other animals to find their way. One of the most prominent of the constellations they used was Mahutonga or the Southern Cross. In Mauri tradition the Southern Cross represents the anchor of an ancestral waka (a great canoe) making its way across the sky to new horizons. The rest of the canoe is formed from the Pleiades (the prow), the Hyades (the sail) and Orion's Belt (the stern). These days the Southern Cross takes pride of place on both the flag of New Zealand and the flag of Australia.

Southern Cross
The Southern Cross (Mahutonga) seen from a backpackers hostel in Queenstown, New Zealand. CREDIT: Stuart

Posted in astro blog by Stuart on Saturday 18th Feb 2006 (08:29 UTC) | Permalink

RS-Ophiuchi

RS-Ophiuchi is a recurrent nova in the constellation of Ophiuchus. It has had outbursts in 1898, 1933, 1958, 1967, and 1985 and apparently it has just gone off again. Quite a few astronomers are having a look now at different wavelengths.

Posted in astro blog by Stuart on Monday 13th Feb 2006 (18:56 UTC) | Permalink

Mt John Observatory

The other day I took an Intercity coach up to Lake Tekapo; a beautiful blue lake that is fed by glaciers in the Southern Alps of New Zealand. The purpose of my visit was to go to the Mt John Observatory which is part of the Department of Physics and Astronomy at the University of Canterbury. The observatory does lots of professional research in the areas of near-Earth object (NEO) identification and gravitational micro-lensing amongst other things.

Mt John Observatory
The Mt John Observatory at Lake Tekapo CREDIT: Stuart
As you might imagine, the observatory is on a mountain (more of a hill really) named Mt John. There is a big cluster of domes spread around the site with some for use by the public. In fact, the area has a growing astronomy-tourism industry and the public-use telescopes are run by a local company; Earth & Sky. Earth & Sky even run a small coffee/refreshment van parked in a little car park just to the left of my picture above. There are also local ordanances to keep light pollution at a minimum and protect the clear skies.

While I was at the observatory I was lucky enough to enjoy the hospitality of Alan Gilmore and Pam Kilmartin. Both of them are very active in astronomy, especially in NEO research and variable stars. Between them they have discovered over forty asteroids - some of which have been given names from New Zealand/Mauri culture such as 3400 Aotearoa and 3563 Canterbury. Alan was also lucky enough to discover a visible nova whilst observing one night. He managed to point a few of the observatory's telescopes at it (with the help of other astronomers observing that night) and so was able to get a good position and even spectra within a pretty short amount of time. These were then sent out to other astronomers around the world as an IAU (International Astronomical Union) circular. In recognition of the discovery, Alan now has a 'Nova' award from the AAVSO on his wall.

Mt John Observatory
Telescope domes at the Mt John Observatory at Lake Tekapo. Some of the Southern Alps can be seen in the background. CREDIT: Stuart
Unfortunately, on the night I was there they had bad weather - it was cloudy and rained most of the night - so I didn't get to see any stars. However, it did clear at some point in the early morning because I woke up to sunshine - typical! Still, it did give me a chance to take the daytime pictures above.

I had a great time seeing a working optical observatory and will write more about it when I have time. Before I left, I added my name to the star-studded (sorry for the puns) visitor book amongst such luminaries as Patrick Moore (Sky at Night) and Aaron Price (Slacker Astronomy). My thanks go to Alan and Pam for looking after me while I was there.

Posted in astro blog by Stuart on Saturday 11th Feb 2006 (23:45 UTC) | Permalink

Morning Star II

Thanks to Peter (and the excellent Stellarium) I have been able to confirm that the planet I saw while driving between the Franz Josef and Fox Glacier was Venus. Peter used the scant information that I provided about directions, together with a rough guess for my location (half way down the west coast of New Zealand's south island) to work it out. If you add some stunning mountains and a glacier or two to the image below that is pretty much what I saw, although the sunrise was a bit less vivid.

Venus
Stellarium screenshot CREDIT: Peter

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Posted in astro blog by Stuart on Wednesday 08th Feb 2006 (09:19 UTC) | Permalink

Morning Star

A couple of days ago I decided to do a skydive. This was because I've never done one and they seem to be cheaper over here in New Zealand than back in the UK. I picked this particular time to do it because I wanted to see the spectacular views of Mt Cook, the Fox and Frans Josef glaciers and the coast while jumping out of a perfectly good plane.

I was signed up for an early morning start (5:30am), so I had to be up bright and early - difficult, especially when you don't want to set an alarm to wake up everyone else in the hostel. At that time it was still dark but the sky was very clear and I was able to make out quite a few stars. On the drive to Fox glacier the sky was brighter (the sun was about to come up) but I was able to make out a single, very bright point of light. My first thought was that it was either Jupiter or Saturn but I realised that it was too far east for that time of the morning. After some thinking, I managed to remember that New Zealand is currently in summer and nearer the equator than the UK, so the plane of the solar system (the ecliptic) makes a different angle in the sky than it did back home a few weeks ago. I now reckon that it was Venus. Perhaps someone with access to a planetarium program (or who knows the southern sky) can confirm it.

Oh, and the skydive was utterly amazing.

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Posted in astro blog by Stuart on Monday 06th Feb 2006 (23:16 UTC) | Permalink

Southern skies

The other day I had one of the most fantastic experiences ever. I went on an overnight sea-kayaking trip along the coast of the Abel Tasman national park which sits at the top of the south island of New Zealand. The kayaking was lots of fun - on a sea only slightly more rough than a mill pond - the scenery was beautiful and the wildlife was everywhere; I got to see orcas for the first time as they swam past my kayak. As it was an overnight trip we stayed on a tiny camground next to the beach in the remote Bark Bay. The sky there was black and thousands of stars were visible. It was a fantastic sight and I was able to find the southern cross and both the large and small Magellanic clouds while lying on the beach with a few friends I made along the way. It was a magical experience and one I would like to have again some day.

Posted in astro blog by Stuart on Sunday 05th Feb 2006 (08:06 UTC) | Permalink

Put the Moon in orbit

A few weeks ago I came across a page asking 'Can you put the moon in orbit?' (you may need a modern web browser to see this). The page uses scaleable vector graphics (SVG) and Javascript to make quite a nice, basic simulation of an elliptical orbit, but I was slightly worried by the political/theological conclusion drawn from such a simple simulation. In this simulation, if you are to get the Moon in a circular orbit you will need it to start on a circular orbit. The website concludes that "it [the Moon] began its journey in a circle on the circle" and therefore was always like that - a static, unchanging universe apparently 'proved' by a Javascript animation. Unsurprisingly, this argument has made rather a lot of assumptions.

First of all the simulation assumes only two objects and side-steps the issue of more objects (such as would be expected in standard solar system formation theories) by stating that "introducing more particles does not solve the problem it just gives you more problems". Yes it does. Mainly, it makes perfectly circular, unperturbed orbits such as in the animation very difficult to sustain. It also makes life more difficult for the coder who made the animation as they actually have to think a bit more.

Secondly, the simulation simplifies things again by treating the Earth and the Moon as points, even though they get represented by circles and a 'bounce' has been included when these circles touch. This makes for a nice looking simulation but it ignores an important effect; that of tides. If you have ever been to the coast you will have experienced the tides caused by the Moon on the water, but the Moon also creates a smaller effect in the rock on the Earth (and vice versa but that is another story). Constantly stretching and squashing the Earth (even slightly) converts some of the energy from the orbit into heat in the Earth. The results is that the Moon is moving away from the Earth at about 3.8 cm per year. This has been measured by people with telescopes and lasers.

So this simulation is waaaay too simple to be taken as an exact copy of reality. If you were to do a more complicated simulation, including more physics, you could see that a giant impact can generate a Moon like ours with many of the same orbital properties.

As ever, you can't take everything on the internet at face value. It is useful to be a bit sceptical, especially in these days when certain political or religious views try to masquerade as science.

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Posted in astro blog by Stuart on Sunday 05th Feb 2006 (04:36 UTC) | Permalink
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