The Scruffy Astronomer

Bolides, or fireballs, are brightly burning meteors that have entered the Earth's atmosphere. Most small meteors burn up inside the atmosphere, and occasionally they bounce off the upper atmosphere before moving away from the Earth again. These provide spectacular but harmless light shows. Sometimes, however, they cause havoc on the ground. The Chelyabinsk Event in February 2013 was an explosion caused by a meteor about 20m across entering the atmosphere. The explosion released about the same energy as the Hiroshima bomb. Damage was widespread, and several fragments were recovered. Recovered fragments of meteorites are of significant interest to scientists, of course. But how do you find them? The International Meteor Organisation records meteors and bolides reported by citizen scientists. These include visual records, mostly from all-sky cameras, and the occasional sound recording. Scientists can use these to estimate the meteor's trajectory when it entere

February 2021 brought COVID lockdown 3.0 to Melbourne. For five days, we were required to stay home, only leaving for a few good reasons. So what do you do when you're confined to your house? Well, there's astronomy, but the clouds have been clearing during the day and then returning after sunset. I've set up my rig a couple of times, only to tear it all down after an hour of staring at a starless sky. What else can you do? Gardening, of course. Under lockdown 1.0 and especially 2.0, my garden came to be quite neat. Of course, Harley Rose, our new Labrador puppy hasn't really been good for the garden, unless you regard her as a very enthusiastic rotary hoe. And birding. I was out in the garden yesterday, trimming some plants, when I heard a begging call. It was coming from a thicket of Wattles. Eventually I spotted an Eastern Spinebill feeding a juvenile. By the time I'd retrieved my camera and attached the birding lens, the baby had disappeared, but a young

A long time ago I was a bit of a Formula 1 fan. It was cool to see the things those cars could do, and I was fascinated by all the cutting-edge innovations they came up with. But one season Ferrari, so dominant for so long, had poor performance after poor performance. Eventually they got their act together, but it was a season lost. If they can be the victim of the "cascading failure", I shouldn't have been surprised when it happened to me. To quote Adam Savage, failure is always an option. I normally take my images from the the ASV's dark sky site in central Victoria. But during the lockdown, the site was closed, so I stuck at home, and also stuck with planetary imaging as the trees in my garden prevent my tracking a deep-sky target for a long time. Eight months without a deep-sky photo is cold turkey! When the place reopened, I was off like a shot. It was the time of a full moon, but that didn't fuss me. If my image wasn't great, that was OK, I was going

I came across this photo a week or two back on the ASV's astrophotography Facebook page. Sam (the photographer) had posted it because of the nice placement of the meteor, and was very modest about the rest of the shot. I was less focused on the meteor and more on the rest. After all, it's the South Celestial Pole, which isn't really photographed much. Why is it that the polar area isn't commonly photographed? To be honest, I'm really not sure, but two reasons come to mind. First, lots of people think it's a bit of a dead zone. And they've got a bit of a point. You can see straight away that the big area between The Emu (that's the Milky Way through the Cross and Carina) and the two Magellanic Clouds is pretty empty. The second reason is a bit technical. "Plate solvers", those clever computer programs that read stars and compare them to a database to determine where the telescope is pointing, have a bit more trouble in the polar area. T

A while back we sold a Sky-Watcher Esprit to a client. This guy had a slightly old Sky-Watcher HEQ5 mount already, and the Esprit 100 came in under the payload for the HEQ5, so it appeared to be a good match. When he received the telescope, the client found that the Esprit comes with the Losmandy (wide) dovetail plate that the tube rings bolt to. However, the old mount saddle only accepted the Vixen (narrow) plate. This caused us a bit of head scratching. We considered a couple of different solutions, including an adapter (such as Orion part #07952), but that got complex. The simplest solution I could come up with was to change the dovetail plate. The green Sky-Watcher plate is too short, and balancing a scope with a large imaging array (think a full-frame DSLR plus an off-axis guider and camera) isn't possible as you have to slide the scope a long way forward. The dovetail plate has to be longer. Incidentally, for short focal-length refractors, this is a chronic problem. M

This is essentially a bit of fun, but it can have a practical purpose as well. 3D images I've always been fascinated by 3D photographs. Tricking your eyes so that one sees one image and the other sees an entirely different image, is clever. But then when your brain re-integrates those images to form a complete three dimensional structure just spins me out. How? I was vacuuming the floor in the showroom the other day (we have the most wildly exciting jobs) when I found a tiny coil of swarf on the floor. Standing next to a saxon RST Researcher NM11-2000 stereo microscope, I began to wonder how might I take such a photo? I fetched a saxon ScopePix phone adapter and attached my phone to one of the eyepieces. I had to remove the eyecup from the eyepiece to get the phone on straight. I focused carefully and took one photo through the right eyepiece. Then, without moving the sample, I swapped my phone to the left eyepiece and took  a second image.

The other day I mentioned that I'd swapped out my guide camera. It turns out it wasn't necessary, and so now I've got an old ASI120MM in reasonable condition. I decided to try setting it up as an all-sky camera. The camera comes with a fish-eye lens, and all you have to do is connect the computer via USB and use some time-lapse software to make a video. I put the camera on a bit of angle iron and attached it to a mini-tripod (see the photo). I was entertaining vague thoughts of putting it onto my mount for an extra view, but I don't think I can run three cameras simultaneously using ASCOM. For image capture I normally use SharpCap 2.9. It's a free download, although more recent versions have become paid software. As always, setting this sort of thing up takes a few goes. There are options that have to be tested out and tweaked, calibrations like dark frame subtraction to be worked out, exposure times to be lengthened or shorted, output formats that work better

Ever since the Copernican Revolution , we have known that the Sun is the centre of the Solar System. Orbits of the planets don't need to be circular (in fact, Mars' orbit is quite oval), but the one thing that's correct is that the sun is at the centre. Right? Well, not quite. Moving to a heliocentric view of the Solar System was a step forward, but it's more accurate to say that everything in our solar system, including the Sun, orbits the centre of gravity of the whole system. Time for a thought experiment. Imagine you've got a dinner plate, with some items on it. There's a large burger in the middle, a pile of chips on one side, and a restrained amount of salad on the other side (we wouldn't want to overeat, would we?). Now imagine you want to balance the plate on your finger, circus-style. If you don't want to drop your food on the floor, you're going to have to choose very carefully where your finger goes. If you balance the plate