The Scruffy Astronomer

1 February 2019 The Earth's poles are shifting! Are we all doomed? Probably not. One of the things the Earth has always had is a magnetic field. It's mostly caused by the molten core inside the Earth and how it swirls about deep underground. It protects us from solar radiation, produces the most awesome auroras, and it might help migratory birds know what direction to go. It also helps us navigate using magnetic compasses. This includes using a compass to align an equatorial mount (see my blog ). The magnetic field generated by the Earth isn't fixed, but wanders around slowly as the swirls in the Earth's core change their behaviour from year to year. However, in the last few years, there's been a noticeable increase in its rate of change. So what's going to happen? It's hard to say. Because the poles are wandering randomly about, rather than going in a consistent direction, it's difficult to predict what's going to happen. But, becaus

30 January 2019 A planet-sized game of pool? It reminds me of Red Dwarf episode, but that's how Earth got a lot of its elements. I was talking with a customer the other day about water on Earth. We both found it mind-boggling that most of our water came from space in the form of harmless comet collisions. The majority of comets are cricket-ball sized "dirty snowballs". When they hit our atmosphere they turn to steam, and fall as rain. But what about the other stuff? Over 4 billion years back, our newly-formed Sun was creating a giant disc of dust and garbage gathered from previous supernovas in the area. Astronomers call this a proto-planetary disc. They've seen it happening around other new stars as well well - this photo is from a system called HL Tauri. In this disc, elements were gathering in bands at different distances from the centre. It's really an astronomical-sized centrifuge. As planets formed in the disc, they started off with just the elemen

28 January 2019 FRBs... WTF? A fast radio burst (FRB) is just that - a single huge blast of radio energy that lasts only a few milliseconds and then stops. It's the radio version of a cosmic camera flash. What's more, there are only two sources that are known to have flashed twice. All other recorded events seem to be random. The amount of energy contained in a single FRB would power our sun for about 80 years. That'd expose a lot of film. The one thing we are really sure about is that they come from well outside our galaxy. But as to what causes them, we really only have theories. Astronomers have speculated that they might be caused by collisions of black holes or neutron stars, or that they might be linked with gamma ray bursts (look these up - these nasties are an actual existential threat to the Earth!). Of course, astronomers haven't been able to rule out artificial sources either. Alien selfies? Canada has just finished building a new type of ra

25 January 2019 With Australia Day coming up, you probably know that the Australian national bird is the Emu. I saw my first Emu in 1976 when I first went to Wyperfeld. But what about the various state birds? The South Australian bird is the “Piping Shrike”, which we know these days as the Australian Magpie. The Western Australian state bird is the Black Swan. You probably know yours, if you live in a different state (look here if you don't). The Victorian state bird is the Helmeted Honeyeater, which is in fact a subspecies of the Yellow Tufted Honeyeater. It's obviously different though, with a distinctive crest running between its eyes up to the top of its head. Helmeted Honeyeaters are listed as critically endangered, and restricted to a very small area at Yellingbo near the Dandenong Ranges. They're a swamp-dwelling bird, and by all accounts they're cranky, and are unable to get along with other birds well at all. If all the other states have relatively

23 January 2019 Interactions between gulls and humans, including infrastructure. Good or bad for the bird? Everyone knows that gulls come in large flocks, and that sometimes these flocks can be a nuisance. Famously, flocks of gulls on the beach love to mob people eating hot chips. At the cricket, sometimes the ground is crowded with Silver Gulls. It can be a bit of a problem. Occasionally, a particularly well hit ball hits a gull on the way to the boundary. Remember the "Sammy the Seagull" incident a few years ago, when the bird was stunned by the ball ? It all ended well though, when the gull was carried off the field and subsequently recovered, much to the amusement of the crowd. Sometimes the interaction isn't in the best interests of the gulls. A recent thread on the Birding-Aus newsgroup suggested that highly lit infrastructure (think stadiums or something like the Arts Centre tower in Melbourne) is a risk to birds like Silver Gulls. The jury is still out

21 January 2019 Cotton on the Moon? You probably heard that the Chinese lunar probe, Chang'e 4, has successfully germinated a cotton seed. Of course, it was never going to last long. China's space agency reported that all the seedlings in the experiment had died, only having lasted a few days in their special chamber. There's no prospect of having Moon farms growing cotton for terrestrial use. Most of the explanations given by biologists about this is that the lunar night was coming. A day on the Moon lasts for about 28 Earth days, meaning it's night for about 14 Earth days. And it gets cold. Seriously cold. "Overnight" temperatures on the Moon go down to as cold as 180 degrees Celsius below freezing. Even in the biosphere there was no chance of fending that off. Of course, the temperature problem reverses when the sun comes up again. "Mid day" temperatures on the moon get up to 100 degrees Celsius, boiling anything that has water. Why

18 January 2019 What's your favourite opera? A few days back, we had some opera lovers in, looking for gifts. Of course we got talking about our favourite operas. Our clients were big on Puccini's La Bohème and Mozart's Don Giovanni. These are grand operas in the traditional style, with story, drama, costumes, ceremony, and ... oh, everything! Because I'm a simple sort of guy, I prefer a minimalist style, like Einstein on the Beach by Philip Glass or Nixon in China by John Adams. The music is mesmerising and the story is ... bewildering. My wife prefers operetta, like Gilbert and Sullivan - particularly the Pirates of Penzance. Just plain fun. The customers bought a couple of saxon opera glasses, which are very small binoculars. Traditional opera lovers are likely to favour the traditional designs . I think that John Adams would prefer the flat square ones through. They're higher magnification, too. What's more, if you're attending the Au

16 January 2019 A variable ... nebula? Well, not really, the nebula is just a cloud of dust and gas. The cloud is the same, but the star that shines on it suddenly brightens every so often. McNeil's Nebula is right next to M78, which is in the constellation or Orion. What's weird about it, is that it was only noticed in 2004 - and by an amateur astronomer using a 3-inch scope in his back yard. (Yes, there's hope for us yet!) Further searching in the archives turned up images showing the nebula from 1951. What had happened was the variable star at the bottom end of the nebula brightened suddenly, and we could see the surrounding dust. The star is just visible in the first photo below, marked with a big yellow arrow. It looks like someone shining a torch around inside a cave. You can see small areas of the cave walls when the torch is close, but normally everything is dark. The final chapter in the story is that the star has now become so dim that the dust cloud

14 January 2019 After two nights up at the dark sky site photographing NGC 2736, I (Bill) have finally had the chance to nip out to the poo farm in Werribee (armed with binoculars, ancient Kowa scope, ScopePix and DSLR) for the Tufted Duck. This is the first time a Tufted Duck has ever been recorded in Australia. They're commonly seen in Europe, and can come down as far south as India or Japan. So you can understand that it has made quite a commotion in South East Australia! Of course, there are a number of questions arising from this, like how did this male get here, how long will it stay, and will it turn into Falcon food, You can see the photos I got below. The photo taken with the saxon ScopePix can't compete with a DSLR on a tripod with a 500mm lens, but at one fiftieth of the price and about the same proportion of weight, it can make the difference between ticking the bird and dipping!

11 January 2019 Ever seen the International Space Station fly over? Bill's blog tells you how to spot it, how to find out when it's going to be over your house, and how to see it best. It's not difficult to photograph as a time exposure, as the photograph here shows. All you need is a camera that can do long exposures and a tripod. And the knowledge of where it's going to be, of course!

9 January 2019 About this time of year, birdwatchers start looking into the sky for Swifts. They're relatively common up North in the tropics, but down here south in Melbourne, they're a bit of a rarity. There are two common types, which used to be known as the Fork-tailed Swift and the Spine-tailed Swift. Taxonomists are nearly as bad as astronomers, though, and so they had to change their names - to Pacific Swift and the White-throated Needletail, respectively. The easiest way to tell them apart is by looking at their underparts (that's what you're going to see as they fly high above you). The Needletail's neck and rump are white, whereas the Pacific Swift is more uniform underneath, with a dark rump and maybe a slightly lighter chin and neck. Although they do land occasionally, Swifts spend most of their time on the wing. I understand that they even sleep in the air, taking little naps while on autopilot. Their food consists of insects that are stirred up

7 January 2019 Just came across what has to be the birding photo of the week (not that we have such a thing) from Wayne in Ararat, via the Victorian Birders Facebook group. He says: " Above the Gardens, a Masked Lapwing leads a Silver Gull in a fly by. Impossible to expose for both, for me." I reckon this photo's got it all - it's cropped beautifully, while still maintaining a narrative. The Lapwing is accurately focused with the Gull just out of focus, enhancing its pursuit. The spurs on the Lapwing's elbows are also nicely visible. Finally, the birder in me is especially intrigued by this photo because it's normally the Lapwing that's chasing the Gull! Great shot, Wayne.

4 January 2019 NASA probe update: a couple of things are happening at the same time. The New Horizons probe has just done its scheduled fly-by of Ultima Thule, and found that it looks like a 35 kilometre long bowling pin, spinning slowly in space. Ultima is way out, beyond the orbit of Pluto, and New Horizons is going pretty much flat out, over 50,000 km/h, with no way of stopping. It'll probably use its remaining fuel to change course so it can do a fly-by of another Kuiper Belt object. At the same time, the OSIRIS-REx probe has gently settled into orbit around Bennu, an asteroid relatively close by - just beyond the orbit of Mars. This is the smallest object so far orbited by a probe, so orbiting is tough due to Bennu's incredibly small gravity. One wrong move and OSIRIS-REx will drift away into interplanetary space. But when I think of planetoids (asteroids, Kuiper Belt objects, call them what you will) I tend to think of Vesta, the second-largest asteroid (after Cer

2 January 2019 One of the most common questions people ask us is "what's that little telescope on the side of the big telescope?" It's called a finderscope, and it's put there to help you aim your main scope quickly and accurately - or at least enough to get the object you're trying to find into the field of vision of your high-magnification telescope, saving you from hunting around and around. Bill's written a new blog on what the common types of finderscopes are, how to use them, and how to turn these things from dust collectors into time (and frustration) saving tools.