Megan's Blog

Trying to find Southern meteors....

After the sucessful operation of the Jodrell Bank Observatory Meteor Detector (JBOMD) for over a year now, I'm trying to set one up here in Perth. Luckily, there was a scanning receiver in the lab identical to the one the JBOMD is using so all my control scripts work out of the box. Over the summer break (yes, it's hot down here at this time if year) I've set the thing up on the roof with a dipole and a little amplifier and set it scanning a bunch of frequencies in order to find a likely place to spot some meteors, logging to a laptop so that all I have to do is check the data when I go back to work.

What you need is a transmitter in the TV band which is far enough away that you don't normally pick up the signal, but near enough that there is still enough power after the signal has bounced off the ionised trail of a meteor in the upper atmosphere and traveled back to your antenna. What I've found so far is lots of funky-looking interference, but no meteors. It's early days yet, and this experiment is just to investigate likely places to start looking in more detail. In the Southern hemisphere, January is a good time to be looking as the meteor rates are fairly high.

Stay tuned.

There was another cool view of the planets last week. One great thing about living on the river is the fantastic low horizon to the west. This shot was taken from the top of the bridge over the freeway at about quarter to ten in the evening on December 29th. Mercury is there, honest, you might have to play with the contrast on your monitor to see it though. High above them was Venus shining away brightly, but my old little camera isn't quite that good (it's now six years old and the battery cover is held on with gaffer tape...).

A Cosmic smiley

Last night was a District meeting at Lynwood. After the meeting finished, I dragged everyone outside to look at a very strange sight: a smiley face in the sky! Although I didn't see the news yesterday, apparently it was on the ABC in the evening, so lots of people did go outside to have a look. I only had my old digital camera with me, but I tried to take a photo anyway. An hour later when we left the hall, Jupiter had moved a bit and the face looked quite lopsided!

It was far more successful than the observing I was going to do last weekend. We took our Scouts camping again and Womble brought along his telescope, I took my binoculars. Friday night was really clear, so we got out the telescope and looked at a few things, Orion was rising over the trees (he's standing on his head down here, that always makes me laugh) and the Pleiades wasn't far behind. To the South we had a good view of the Magellanic clouds. On Saturday I'd invited a group of Cubs who were camping up the track to come over and look at some stars with us. We made the mistake of having a campfire though (last one before the fire ban kicks in this week). It was a good campfire, the patrols came up with some very funny stunts and we sang a lot of songs, but I led the rain song again and within half an hour it was starting to spit! Of course I'm now blamed for this, and everyone who was camping up there that night now thinks it was my fault! I don't know, summoning the rain is a pretty useless thing for an astronomer to be able to do...

The Murchison Widefield Array

Last week I was up in Geraldton again at a project meeting of the Murchison Widefield Array (MWA) team. I'm not on the team, but I was invited along anyway, and I picked up a lot over the four days of the meeting. It's a pretty cool project but, like all projects, it has it's problems.

Basically, the MWA is a telescope with no moving parts. It's a series of dipoles which sit on the ground on top of a mesh groundscrren, sixteen dipoles making up one "tile". At the moment, there are 32 tiles up at Boolardy station with plans for 512 sometime in the next couple of years. The dipoles on each tile are connected to a beamformer which does some funky stuff to the signals before sending the data on to a receiver. Each receiver takes the inputs from 8 beamfomers, does some more funky stuff and sends the data on to the correlator.

What this all adds up to is a telescope which is steered electronically. In a conventional interferometer, to look at a different part of the sky you have to move all your telescopes and then adjust the delays added to each signal so that the wavefronts of the signals all line up (it's kind of like the Youngs slit experiment). With this sort of telescope, the dipoles can "see" most of the sky at once, and to make an image of the patch you are interedted in, you can adjust the delays in electronics to steer the beam.  This is one of several SKA demonstrator telescopes which are testing out technologies and methods in preparation for the Square Kilometre Array.

It's all very interesting stuff and after spending a day in the lab annoying the engineers I think I understand it a whole lot better. There's still a lot I don't know though, but that's half the fun of research!

Remote outreach!

This week, together with Rob Hollow and Mary Mulcahy from the ATNF, and Steven Tingay from Curtin, I went up to visit a remote school in an aboriginal community at Pia Wadjarri to do some outreach. We met up in Geraldton on Monday and headed out to Boolardy station on Tuesday morning, a drive of several hours in a 4x4 along mainly dirt roads through low scrub. The area is incredible, so different to what I'm used to back in the UK. It is pretty remote, and we were very glad of the satellite phone when the 4x4 broke down 130km north of the nearest bit of tarmac and 70km short of the nearest settlement of any size! We spent four hours trying to escape the afternoon Sun by hiding under a small tree.

The rest of the trip went really well. We went to visit the site of the Murchison Wide-field Array (MWA) and the Australian Square Kilometre Array Pathfinder (ASKAP) early on Wednesday morning, and it's fantastic. Between the MWA tiles and the ASKAP cabin, there's a breakaway which is the only height for miles in any direction. We climbed up and had a look out over the area, a huge expanse of land with hardly a person anywhere. It's very remote, and so quiet. I love it.


Then we went to the school at Pia to do a day of astronomy activities with kids from the reserve and a group who had come up from Yalgoo to join us for the day. We had planned to get out telescopes in the evening after sunset and do some practical astronomy, but it was too cloudy in the end. We did plenty of other stuff though: solar system games, looked at the Sun, raced balloon rockets and launched water rockets. It was great!


It was a fantastic week, despite the problems with the 4x4! I'm hoping to get a chance to go back there at some point though: I spent ages looking for some decent slide film for my old SLR especially for taking some astrophotos on this trip, but it was cloudy every night!

More Scouting antics

Not long after I joined my Scout Troop Possum, out Group Leader, asked if I'd like to go to CampWest. This is a big camp held here in WA every three years - it lasts for a week and is preparation for those that want to attend the Australian Jamboree. My response was "absolutely!" I've always loved camping, and it's ten years since I last went on a big camp so I was keen to go along. This year the camp was at Manjedal, the Scout campsite near Byford, just south of Perth and had over 800 Scouts attending. There were around 200 leaders as well, so over 1000 people altogether. The Scouts from my troop were camping together with Scouts from Gosnells and Wanerro on one campsite called Kim's Track 2. As well as me, another leader from our Scouts went as well. I was allocated to the Activities Team so, while I was camping with my troop, I spent my days working at one of the activity bases (I got to play with pioneering gear for the whole week - brilliant!). Womble, the other leader from my troop, was given the job of QM for our campsite. His job was to organise the equipment for our campsite (about 45 Scouts plus 8 leaders) and the catering. All the food was provided, but the duty patrol on each campsite had to cook the meals. Big camps work a bit different to how we used to do it with Guides in the UK, so I learnt a lot in the first two days!

It was a lot of fun though, apart from the disaster with the vegetarian options (there weren't any for the first few days!), and I had a great time. The next Australian Jamboree is in 2010 in New South Wales and I can't wait! First I've got to plan my activity base for Escape in January though...

Last weekend was full of Scouting things as well. On Saturday, Womble and I went out on the Bibbulmun Track to check out a campsite we're planning on using for an overnight hike in a few weeks. It turned out to be a really good spot, and the weather was perfect for hiking. Then on Sunday we went down to help at the Moreton Bay Fig Festival, an annual community event organised by Victoria Park. The Scouts were running a craft stand and manning the community sports trailer so I spent most of the afternoon playing volleyball with random people! I helped out on the portable climbing wall for a while too (they were swamped with people and needed a break for lunch) so I got to have a go before they packed up.

This week is the start of term four, the schools have just been on holiday for two weeks. The programme for the term is looking like a lot of fun: as well as regular meetings we've got the overnight hike, a camp, a day playing with the canoes out on the river, a barbecue at Kings Park and this weekend is JOTA! Should be fun!

I get the feeling that Scouts has taken over a bit, but I don't care, it's fun. (And nobody has mentioned the "G" word yet....)