The Scruffy Astronomer

The other day I was contacted by James in Philadelphia who has just got himself a Celestron AVX800. A fine scope on a fine mount. But he’s having trouble with the 9x50 right angle correct image (RACI) finderscope. I had a look at the "straight through" one on our display model and yes, it’s fiddly. When you set up the scope each night, you have to true up the finderscope so that it's parallel with the main scope. To do this, you use the adjustment screws at the back of the bracket. This design is the "two screws" type - at 12 o'clock and 3 o'clock (see my side-by-side photo below). They work against a spring-loaded pin at 7:30 (which I've circled in the finst photo). Other finderscope designs use three screws spaced equally around the finderscope. To adjust the spring-type finderscope, all you have to do is twiddle the screws at 12 and 3 o'clock. You don't have to back off one screw in order to advance another, which you have to do with the t

I think you've seen this photo before, but I'm hoping to talk more about clusters you can see from suburban back yards. I also want to talk about what you'll see with telescopes of less than $500. This is NGC 4755, the Jewel Box. It's probably the most well-known and popular star cluster in the Southern Hemisphere. Why? There are several reasons. The cluster is easy to find - it's just outside the very recognisable Southern Cross. It's also very pretty, with a range of coloured stars in it. There are white stars, a number of red-yellow stars, one really red one, and some blue ones. It's just made up of stars, which sounds obvious, but this means you don't need to find anything really dim. In turn that means it's good for inner-city viewing where the background is grey or brown rather than black. One catch, it's not very big. If you've got a telescope with a focal length of less than about 700mm, you will need a 10mm eyepiece to get a nice vie

The Winter Solstice is on Monday, the 21st. In many countries, the Solstice is the official start to Winter. After this, while the Southern Hemisphere gets more sunlight, the cooling by radiation into space is still greater, meaning the coldest weather is just starting. This date coincides with the new Moon - so it's a great weekend for astronomy - weather permitting. I've prepared a list of things for you to find. If you’ve got a small scope, look for the Moon, larger planets and star clusters. If you've got a Dobsonian, you can see dimmer objects. My target this season is the Lagoon Nebula. I've never got that before. This one is Josh Carnovale's. I've sorted the list by the time each object passes the meridian, so start at the top of the list. Clear skies! ⦁    Mel 111 - Coma Berenices Star Cluster (06:55 PM) ⦁    M87 - Virgo A Galaxy (06:55 PM) ⦁    M104 - Sombrero Galaxy (07:09 PM) ⦁    NGC4755 - Jewel Box Cluster (07:24 PM) ⦁    NGC5128 - Centaurus A Galax

With the travel restrictions lifted, I decided to go for a couple of nights to Wyperfeld National Park, near Hopetoun in Victoria. It's a pretty hefty drive, and with stops, it took me about seven hours to get there. But if I don't get out of the city regularly I get a bit testy. Wyperfeld hosts the terminal lakes of the Wimmera system, and I've been coming here regularly since 1976, when it was properly flooded. The desert birds here are wonderful, partly because they're different to the ones we see in Melbourne, and partly because they're impressively tenacious. The three birds I wanted to see here are Redthroat, Mallee Emu-wren and Shy Heathwren. All hard birds. Shy Heathwren Mallee Emu-wren Redthroat They're all "allegedly" possible on the Discovery Walk to Lake Brambruk. So early in the morning, I dragged myself out of my tent and set off. The last ridge before Lake Brambruk is the spot. My birding friends call me "Bill the Dipper". I t

We're getting towards the best time for viewing planets. Jupiter and Saturn are both above that critical 30° angle for good viewing before midnight. Pretty soon they'll be high in the sky at an hour that will have you asleep soon after midnight. And later in the year they'll be joined by Mars. Opposition - the point when the Earth and Mars are closest, and the planet is highest at midnight - is in late October. People are beginning to take great photos already, and you don't need hugely expensive equipment to do it. It's fantastic what you come across when you subscribe to different Facebook groups. I was browsing through one of my favourites the other day, "Budget Astrophotography", when I found these.   Adam lives in Tucson, Arizona, and took these using a manual 8" Dobsonian scope, and an iPhone 6 clamped to a 9mm eyepiece using a Celestron NeXYZ phone adapter. Each one is a single exposure - there's no stacking. I contacted Adam to find how

I've posted a couple of times about space junk, useless stuff left in orbit, a couple of times before. Space junk can grow on its own, through collisions which cause more debris which is less predictable. But worse, collisions cause more collisions, and might at some stage cause a "cascading Kessler Syndrome", effectively closing space. But at this stage it's deliberate collisions that might be the threat to watch. At least four countries are developing kinetic anti-satellite weapons, also known as "hit-to-kill" weapons, either against incoming ICBMs, or other satellites. Debris from a Chinese test in 2007 damaged a Russian satellite two years later. More debris from the same test passed within 6km of the International Space Station in 2011. More recently (in March 2019), India successfully demonstrated its own capability. The test was deliberately carried out in a low orbit to limit the spread of debris, but recent reports from the Arms Control Wonk claim t

It looks like the restrictions combating the Coronavirus might soon start getting wound back - at least until a second wave of infections comes, I suppose. For the last seven or more weeks schools and many businesses have been shut, and people have been asked not to travel or even go out unless there's a good (and specific) reason. So of course, during this time we haven't been allowed to travel far. For me includes travel for birding as well as astronomy. I like to get out of the city, particularly into the desert, for birds, as well as for general mental health. I'm also pretty regular at the ASV's dark sky site for astrophotography. Instead, I've been walking - normally with Mickey the Labrador - in a number of local parks, all of which are near the Yarra, the river flowing through Melbourne. When the weather is sunny, I sometimes take my birding lens, and I've taken photos of birds I've seen in my travels. None of them are especially rare, but it's n