The Scruffy Astronomer

We've uploaded another video onto the Optics Central YouTube channel. This one is me unboxing the saxon Astroseeker 15075. This is a 6-inch Newtonian on a light computerised alt-azimuth mount. The mount is a nifty little unit, well capable of carrying the weight of the tube. It's a heavier duty mount than the SkyWatcher mini AZGTi, and is capable of taking a heavier tube than the Newtonian here. In fact, this mount is often found with a 127mm Maksutov. The mount can be controlled by the hand controller that's included in the box. Alternatively, because the newest versions of the mount have a built-in WiFi connection, you can also control it using the SynScan app for your phone. The tube is a standard Newtonian, with a parabolic mirror and a focal length of 750mm. This makes it an f/5, meaning it's good for deep-space objects, such as galaxies and nebulas. Star clusters and the Moon are also well within your reach, especially in light polluted areas, but planets wi...

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...

Most high-end mounts attach to the telescope using a dovetail clamp. The telescope itself has a dovetail bar on it, which has a trapezium cross-section. This normally bolts to tube rings, which encircle the tube so they don't crimp it in any one spot, but some light tubes bolt directly to the dovetail. All you have to do is open the clamp on the mount, slide the telescope in so the clamp goes over the dovetail, and wind the clamp shut. Simple. The main advantage of having a clamp is that it keeps your scope parallel with the RA axis on the mount. It also doesn't scratch your dovetail bar. But are there disadvantages? I certainly never thought so. However, last time I was up at the dark sky site I was talking with far better astronomer than I, past ASV president, and general all-round good guy Russell Cockman. Russell was looking at my rig and brought up the subject of dovetail clamps. He asked me if I was scared of using one. This is my previous scope sitting on its mount...

More than anything else, people ask me about polar alignment of beginner equatorial mounts. To be honest, I'm not really sure that beginners need equatorial mounts at all, but that's how a lot of telescopes come. The process seems intimidating and hard to understand, but once you get the idea, it takes about five minutes and you're up and running - especially if you're putting the scope up where you had it last. In this rather lengthy blog (that goes with a video ) I go through the stuff you need to know to get your equatorial mount set up, as well as a load of details you don't need to know, but might be helpful. Before you start Just to keep you on your toes - or maybe to balance the information coming from elsewhere, I live in Australia, which is in the Southern Hemisphere. I can't see Polaris, meaning the procedure might be a little different if you're up North. Some people say that polar alignment is easier in the North, I'm not entirely convinc...

This is what you can do with a small star tracking device. Steve from Tassie recently got himself a Sky-Watcher Star Adventurer, which is like a small equatorial mount designed to carry a camera and normal lens. Steve used his Lumix G9, a micro four-thirds camera with a 200mm f/2.8 lens. This gave him the equivalent of 400mm focal length for a full frame. Using ISO 1250, he took 12 30 second exposures, which he stacked using Affinity. Final touches he did in Apple photos. As to the photo, it’s one of my favourite areas in the sky, the end of the Rho Ophiuchi dust trail. There’s so much there. Just for fun, I've put an annotated version of the photo at the bottom. The bright yellow star is Antares, the eye of the Scorpion. Above and to the left is the globular cluster M4, but between them is the smaller cluster NGC 6144. Continuing anti-clockwise, Alniyat is next, and then the smaller star HIP 80079 to the left of the shot. Below this is (for me, at least) the star of the show, Rho ...

Our recent competition for wide field astrophotography was won by Clint Conn, and I’ve attached his photo here. Stunning. I’ve taken a few in my time, but never this good. To take a photo like this, you can use a simple tripod and a camera. But you can’t expose for longer than about 30 seconds (depending on your focal length) before you start to get star trails. These can look nice, but if you don’t want them, it’s awful. You have to stop the stars’ apparent motion. A gigantic equatorial mount under your camera would do the job, but that's bulky and expensive. What's worse, your camera would look a bit ridiculous on top of a thumping great machine. You need a simpler and less expensive gadget that tracks the stars. There are several types out there, such as the Sky-Watcher Star Adventurer, or the Vixen Polarie.     You align them to the South Celestial Pole, and once they’re set up, they enable you to take photos of the sky using a camera and a normal lens. To ...

25 December 2019 Merry Christmas to all our customers and readers! To everyone who's having a break over Christmas, I hope you all have a relaxing and safe time. To the rest of us, try to keep cool - it's been a hot start to the summer so far. This isn't great for astronomy, for a couple of reasons. First, hot weather makes for poor "seeing", with the atmosphere boiling away, causing light to be dispersed one way then the other, and ruining your view. It's like looking through heat haze, and you can see it in a little sequence I put onto our YouTube channel . The second reason why the hot start to summer isn't good for astronomy is the smoke. It's been a bad bushfire season so far, and looking through smoke haze doesn't make for good views. Incidentally, the heat isn't good for birds either. City birds will do all right, not being far from sprinklers and other water sources. But in the bush, the dryness and heat will really thin the...

Go-to mounts are great Many of our Sky-Watcher or saxon telescopes come on computerised mounts. These are great, and allow you to quickly find stars, planets and other targets without having to slog your way through star maps. But they need to be aligned For go-to slewing to work, you have to align the mount to the sky when you set up the scope.  Sky alignment allows your mount to know which way it is pointing. Telescopes, like planes and boats, change directions in three ways: pitch (up and down), roll (twisting clockwise or anticlockwise) and yaw (left and right). Roll, for an alt-azimuth mount, such as a Sky-Watcher Star Discovery or a saxon AstroSeeker, really isn't much of a problem. This is because your mount should be close to level, and you're not going to move it anyway. To set pitch (known in astronomy as altitude ) and yaw (known as azimuth ), though, you're going to have to show it some stars before it can take over. There are a number of different...