Showing posts from March, 2019

Expanding Crab Nebula

29 March 2019 I was talking with a mate the other day about these Facebook posts, when I casually mentioned the one I'd done about the expanding Crab Nebula.  Duh, turns out I'd never posted it! So here it is.   The Crab Nebula (M1) was formed by a supernova in 1054, so a little under 1000 years ago. People saw it from the Earth. Supernovas are big bangs. The gas and dust ejected from the exploding star formed a massive nebula with criss-crossing shock waves further interacting with clouds of hydrogen, oxygen and other gases and elements. It's a very complex nebula - a little like the Tarantula. But the real point is that it's still expanding. So fast, in fact, that you can actually see it growing in a time-lapse taken by Detlef Hartmann over a ten-year period . I would definitely recommend having a look at the Crab Nebula - it won't move while you're watching it, of course, even though it is expanding at about 1000 km pe

Meteorite on the Moon

27 March 2019 Meteorite on the Moon January 2019 Australian sky watchers didn't get to the see the latest total lunar eclipse, as it was all done from start to end while the Moon was around the wrong side of the Earth. Pity, it was called a "Super Blood Wolf Moon", which sounds cool. While I know what all the other words mean, the "wolf" escapes me.  Something a marketing team dreamt up perhaps? However, there was something a bit unusual about the event. Soon after it began, a meteor struck the Moon in its darkened side. This caused a good sized flash that lasted for several seconds (some report up to 8) after the impact.  Image: Things hitting the Moon isn't unusual, it's just that during an eclipse the flash the impacts make is that much more obvious. Further, when so many people were watching, it's only to be expected that it the event would be caught on film (or whatever you say these days). What might be

Unboxing video for a Celestron CPC 925

We've added a new video to the Optics Central YouTube channel - two in fact, as it comes in two parts. In the first part , Bill unboxes a new Celestron CPC925. This is a large Schmidt-Cassegrain telescope on a computerised go-to mount.  He goes through the features of the scope, discusses what it's useful for as well as how it fits in with other scopes in the Celestron range. Then he unboxes it, going through what you get in the box. Finally in this part, he assembles the scope, describes its various features and tries to come to terms with the size of this monster. In the second part , Bill shows how the mount works with the Celestron NexStar hand controller, including doing a one-star alignment. He also describes a few optional accessories for the scope. (I hasten to point out that I'm a telescope geek and not an actor!)

Autumn Equinox

22 March 2019 Welcome to the Autumn Equinox! For the stargazers among us, I've prepared a list of things to look at at this time of year - better when the Moon goes away, of course. Some are suited to larger scopes, but clusters work well in small ones. I've ordered it by the time each object reaches its highest point, so it'd be best to start at the top of the list, as these will be starting to set (some don't set at all, remember). For example, the picture is my dodgy effort at M83, which rises at 20:18 and sets at 09:45 tomorrow, reaching the meridian at about 3am. Good hunting! Galaxy: Large Magellanic Cloud (06:49 PM) Globular cluster: M 79 - (06:50 PM) Bright nebula: M 1 - Crab Nebula (07:00 PM) Bright nebula: M 43 - De Mairan's Nebula (07:01 PM) Diffuse Nebula: M 42 - Orion Nebula (07:01 PM) Bright nebula: NGC 1977 - Running Man Nebula (07:01 PM) Bright nebula: NGC 2070 - Tarantula Nebula (07:04 PM) Dark nebula: B 33 - Horsehead Nebula (07:06 PM) Diffuse nebu


20 March 2019 The other day I got involved in a discussion on the Birding-Aus Facebook page about binoculars. You probably know (and if you don't you could easily guess) that among birdwatchers, discussions about binoculars are numerous and enthusiastic. It's a bit like how car people can talk all day about how Ferrari is better than Lamborghini, but most people drive Toyotas or Kias. In the case of binoculars, the big three are Leica, Zeiss and Swarovski. But most birdos start off with something a little more affordable like Bushnell, Pentax, Steiner or Saxon. Here are two of my pairs - my current Nikon Morarch 8.5x56 and an ancient East German Zeiss Jena 8x30. The Zeiss are old, but totally bulletproof. I think they were made so that if NATO ever invaded Eastern Europe they could be used in desperation as tank traps or bludgeons. ...and they're Zeiss. My first was a pair of Vixen Ultima 8x56, which were brilliant in low light, but eventually fell to pieces. I could watch

Finding focus

18 March 2019 You might have noticed that telescopes, particularly small refractors, have multiple uses and configurations.  Mostly, of course, they're used as standalone telescopes. Normally they are used with a diagonals, but sometimes you don't want a diagonal in there. For example, you're trying to look at something near the horizon, or actually on ground. Or you're photographing through the refractor, including using it as a guide scope for autoguiding. This is where the challenge begins. Sometimes, if you take the diagonal off a telescope, and put the eyepiece directly in its place, or if you swap the eyepiece for a camera, you won't be able to get it to focus. In these cases, you'll need a spacer, which is a ring that simply adds distance between the focuser and the eyepiece. These two photos show instances when I've needed spacers. The first is for my main refractor, which wasn't shipped with a diagonal at all. In order to figure out how much spa

Jupiter with the saxon FCD100

15 March 2019 This is my last "you can do it" post about the 127mm saxon FCD100. I've been trying to show what YOU should reasonably expect to get from basic equipment without really complicated technical know-how.  This post is a bit different, as I've used some post-processing in the form of two free programs called Autostakkert and Registax.  I'm a nebula guy with a wide angle telescope, so I've never taken a really good shot of a planet in my life. ( I've published a couple here . They're not much.) So when I say I'm showing what a beginner might expect - I'm not kidding! This is what I did. I took my NEQ6 mount up to the dark sky site and set it up on a pier. I mounted the scope and attached the Orion Starshoot 5MP and cabled it to my laptop. I also used TWO inexpensive 2xBarlow lenses to try to get more magnification. The saxon 127 is only 952mm in focal length, so I was working at about 3800mm effective focal length. I polar aligned usin

Photographing 47 Tucanae

13 March 2019 This is my third "you can do this" post (there might be more, because I'm taking the telescope up to the dark sky site for a shot at Jupiter next). Just to recap, I borrowed the monster 127mm saxon FCD100 triplet APO refractor from work the other day (did I say I love my job?) and set it up in my front yard. The pictures I've published so far have been without any of the magic stuff that the pros use, like autoguiding, stacking or complex Photoshopping. This is a final photo of stars - it's 47 Tucanae, the famous globular cluster near the Small Magellanic Cloud. The first photo you can see is the whole field width (cropped and resized for Facebook, so it's a little postboxy). The photo shows roughly how large 47 Tuc is in the field when using a telescope of 952mm focal length and a normal sized (not full frame) DSLR. This second photo is a crop of the first, because the camera sensor gives us heaps of pixels to play with. I've also used the P

Ultima Thule

11 March 2019 You may remember that the New Horizons spacecraft flew past a strange-shaped Kuiper Belt object in early January. This rock was eventually named “Ultima Thule”. Ultima Thule is a seriously long way away from the Earth, being about 45 times further out from the Sun - it's past Neptune. What’s it doing out there? Well, the short answer is not a lot. Its orbit is boringly round. Other Kuiper Belt objects have a tendency to cross orbits and "encounter" each other now and again. When this happens, one tends to speed up and the other tends to slow down. This affects the eccentricity (or roundness) of both orbits, which can mean one of them gets knocked out of the Kuiper Belt entirely, coming way closer to the Sun. (I don’t want to worry you, but this means “closer to the Earth” as well). Ultima Thule is not ever likely to be this exciting. Phew. But back to its strange shape. From a long time before the New Horizons flyby, NASA thought that the object wa

Space Junk

8 March 2019 There are thousands of operating satellites in various orbits around the earth. Every year, more and more satellites are launched, and while some are "de-orbited", the population continues to grow. OneWeb has launched the first of about 900 "small" (dishwasher-sized) satellites to provide Internet to remote locations. Samsung plans a fleet of 4600 satellites, Boeing is planning about 5000, and SpaceX is planning on launching 12,000 over the next decade. And this cloud doesn't include space junk, like discarded rocket stages, engine shrouds and fuel tanks. What's more, there are hundreds of thousands of smaller bits and pieces up there, ranging in size from a pea to a loaf of bread, and more smaller objects that they just can't track. For example, in 2016, the ISS was hit by something. They're not really sure what it was, but it was probably less than a millimetre in size. This mightn't sound dangerous, but it was doing abou

Long-billed Corellas

6 March 2019 While walking the dog in the park this morning, I came across some bare areas of hard-packed dirt that had been broken up, as though by a small pick. Clearly something had done it, it wasn't some geological thing. The culprit, of course, was a group of Long-billed Corellas. These cockatoos have long points on their upper mandibles that they can use as a lever to get into hard ground. It's said that this long mandible is also responsible for the red feathers on the bird's bib, giving it the nickname of "cut throat bird". A few decades ago, the Long-billed Corella was in severe decline in Victoria. But at some stage, one or more of them they discovered that the introduced Onion Grass had corms that were good to eat, if they could be hooked out of the ground. We don't really know how that information spread throughout the Long-billed Corella population, but these days they're a common bird, even in Melbourne. They're not popular wit

Carina Nebula with a 127mm saxon FCD100 triplet refractor

4 March 2019 This is another "you can do it!" post. If you've been following my Facebook posts, you will remember that I wanted to show what you could realistically expect from your own DSLR attached to a telescope, in a light polluted city. I took an admittedly large saxon FCD100 127mm refractor out into my front yard, got a reasonable polar alignment and started taking photos. I've already posted the photos I got of the Jewel Box. The photos I'm attaching this time are of the Carina Nebula. I think this is the second brightest nebula around after the Great Nebula in Orion, and it's in a good position to be seen right now, being high in the South (and above my neighbours' roof). The single shot I'm starting with was taken with a plain DSLR, 10 seconds at ISO 800. Out of the camera, there's really nothing much to be see, and a lot of people get turned off by this, or try to take a longer exposure, and this can run into tracking problems.