The Scruffy Astronomer

  To be honest, I never thought I'd have the privilege of mucking about with a 5" triplet refractor. I love this job! Introduction The saxon (note the lower case) FCD100 series comes in three sizes, an 80mm, a 100 and the monster 127. It's this last one (www.saxon.com.au/telescopes/ed-refractor-telescopes/saxon-deluxe-127mm-apochromatic-air-spaced-ed-triplet-refractor-telescope.html) I'm talking about here. This is a variant of the scope sold as the Explore Scientific 127ED (https://explorescientificusa.com/products/127mm-fcd100-apochromatic-refractor), however there are a few differences. The focuser on the saxon is the standard barrel-type, where the ES model has a hexagonal focuser, which may be rated to a higher weight limit. First, the basics. This is a five-inch air-spaced triplet apochromatic telescope with Hoya FCD100 ED glass. That sentence alone should have you either bewildered or drooling. Suffice to say, it's a large, high end refractor. Its...

The other day I was alone, imaging up at the dark sky site. My rig is autonomous, which means that once it's going, I can pretty much leave it be. I normally hang about watching it, listening for alarms, and I like to watch it during a meridian flip, but sometimes I go to bed for a few hours. But that night I had a gadget with me to play with, a Celestron StarSense Explorer, the 70mm refractor. It's the baby of the bunch. I hadn't mucked about with it at night before, and this was a good opportunity. I'd already installed the software on my phone, so I set up the scope and fired up the app. I had to align it, and this involved two steps. First, I had to position my phone in the cradle so that the camera is above the middle of the StarSense's mirror. There are a couple of knobs that move the phone around. Second, the camera angle is wide. Somewhere in there is the spot where the scope is pointing, and the app needs to know exactly where this is. I...

An unusual Barlow that's shipped with (at least some) Celestron StarSense Explorer telescopes has to be assembled in an unusual way in order to be able to focus on stars. We’ve been selling the new Celestron StarSense Explorer telescopes for a few months now. The StarSense Explorer is a nifty new development in the world of beginner to intermediate telescope mounts. It uses the camera on your mobile phone to determine which way the scope is pointed by looking at the stars and consulting a database. It then guides you to whatever you want to look at. Very clever. Of course, our stock sold out before we were able to grab one to use as a display model, so I still have yet to play with one. But that’s not the point of this post. The point is the strange Barlow lens that comes with the StarSense Explorers. A Barlow is inserted into the converging rays of the telescope, making them converge less. Put simply, this pushes the focal point (where the light actually converges) further back fr...

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 haven't finished one for a while, I know, but I've put up a new unboxing video on the Optics Central YouTube channel! This one is a Zeiss Conquest Gavia 85, a spotting scope.     Mainly for birdwatchers, the Gavia zooms from 30 times to 60 times, looking through an 85mm objective. I had a fun time taking photos through it using my phone - our test target is a highly salubrious dumpster about 180 metres away on the other side of the car park. Incidentally, the bird on the box is indeed a Gavia Arctica - the Black-throated Diver (or if you're in the US, I believe they're known as the Black-throated Loon). I've never seen one - I've seen a Red-throated in Norway, will that do? You can see the video here .  You can find the whole of the Optics Central YouTube channel , including all the other times I've made a goose of myself.  Enjoy.

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 ...

Last month I went to the ASV’s Star-be-cue. The weather didn’t really play the game, and for most of the evening we were dodging clouds. But star parties are mostly social occasions, and a chance to meet up with other astronomers. They're also a good opportunity to see other people’s equipment and how they use it. While I was there, I got talking with a couple of people with a saxon Novo 909AZ3. They were watching M42 - the Great Nebula in Orion. Nearby, another group of people were also on M42 but through a saxon 8” Dobsonian. I had a saxon Hyperion 1021EQ3, so it was a great opportunity to compare scopes. The 909 and the 1021 produced very similar images. Although M42 was visible, it wasn’t very extensive. However, because these are both refractor telescopes, the “trapezium”, those four baby stars in the middle were sharp and bright, clearly separated from each other. The Dob gave a very different view. M42 was wide and very distinct. You could see wisps of it extending on b...

28 October 2019 I've been busy blogging on lists lately. The latest one is the " top 10 telescopes for 2019 ". This is different to the Christmas gift list as I wasn't restricted by price (mwa ha ha!) In order to narrow it all down, I split the competition into categories, so I've chosen the following: Two basic scopes Two telescopes for viewing planets One telescope for viewing galaxies and nebulas One scope for short period astrophotography Three scopes for long period astrophotography (can you guess why?) One scope for terrestrial viewing One pair of astronomical binoculars Have a look at my choices and see if you agree or disagree. If you have any other suggestions, let me know in the comments. I'll be particularly interested in hearing from people who have bought scopes and what they think of them. Incidentally, I took the glamour photo of the Esprit 100 while making the unboxing video . Its proud owner knows who he is. He also kno...

19 October 2019 We’ve just uploaded a new unboxing video . Optics Central’s astrophotographer, Bill has unboxed the latest version of the Sky-Watcher Star Discovery 127mm Maksutov. This is a small telescope with a lot of magnification, and the 2019 version has an updated handbox as well as built-in wi-fi. The scope itself is compact but has a long 1500mm focal length, making it a planetary specialist. You can see the larger planets in some detail, as well as seeing individual craters on the Moon. The scope comes on a computerised go-to mount, which now has built-in wi-fi, meaning you have a choice between controlling it with the hand box or by using the SynScan app on your smart device. Either way, you will be able to choose from a list of 42,000 objects, and the telescope will move itself to locate them for you. Go watch the video and see for yourself.

One of the telescopes that we demonstrated at the recent open night was the 127mm saxon FCD100 triplet refractor. This is an astounding piece of equipment (people probably noticed me hogging it all night). I'd actually taken it home to do some testing on it previous to the open night. After all, I can't properly demonstrate something I haven't used, can I? One of my favourite test subjects was 47 Tucanae. It's bright and not hard to photograph, but it's complex enough to show up any problems with your equipment such as chromatic aberration (or coma if you're using a Newt). These photos were taken from my front yard in suburban Kew, so light pollution was always going to be a major problem. This is the image I got, without much processing. All I did was boost the whites (but not the highlights because I didn't want to overexpose the stars) and deepen the blacks (to get rid of the worst of the light pollution). It's fairly heavily cropped. To give you...

We've just released a new video on our YouTube channel! Sky-Watcher Esprit triplet refractors are about as good a scope as you can get, without having to sell your house. Have you ever noticed odd colours around bright stars in your field of view? In particular, are you irritated by blue halos around these bright stars? Red fringes on the edges of the Moon? This is chromatic aberration. For astrophotographers, it's maddening. Esprits reduce chromatic aberration to nearly undetectable levels. "Triplet" type refractors do this by having three carefully designed and made elements in the objective group up the front end. This means that the colours can be focused sharply all at the same spot, eliminating all those false colours. Sky-Watcher Esprit scopes come with matched field flatteners, which improve your astrophotography further. Without a field flattener, if you focus on a star in the middle of the frame, the stars on the outside are slightly out of focus. In...

24 May 2019 Bill (er, that's me) has done a new video for the Optics Central YouTube channel. This time I've unboxed a CGX 800, which is a Celestron CGX equatorial go-to mount with a Celestron 8" Cassegrain telescope on top. Not the biggest scope and mount we have, but plenty large enough. The video is in three parts. Part 1 is me showing off the three rather large cardboard boxes, and then opening each in turn. Like a kid at Christmas, I take out all the parts and spread them all over the floor in the showroom. In Part 2 I get all those pieces and build the tripod, mount and telescope, going through all the parts in turn. In Part 3 I turn the mount on and show a little about how it's aligned. Of course I wasn't able to do a great job for this part because it's during the day and we're indoors! I hope you get the idea though. For astrophotographers, however, I didn't go through the Celestron "precise polar alignment" routine...

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!)

1 March 2019 You can do this! I've been contacted by a couple of people who say that the photos I publish don't give a realistic impression of what a customer can expect to be able to get. So, in something of up-to-date news, I'm in the middle of evaluating (see also playing with) a saxon FCD100 127mm triplet APO refractor (https://www.saxon.com.au/saxon-deluxe-127mm-apochromatic-air-spaced-ed-triplet-refractor-telescope.html). The idea here is to see what sort of photos you can get with JUST this telescope and a DSLR (and a $30 t-ring to hold them together). Yes, that's right, no chilled CMOS, no filters, no autoguiding, no autofocus, and no magic post-processing. Just a tracking mount (in this case an unvarnished, slightly used, NEQ6, driven by a handbox). So last night I went out into my front yard, under the street lights and Kew's light pollution, polar aligned by finding Sigma Octantis with my binoculars (which was pretty rough), and fired off a SI...

8 February 2019 I got to spend some quality time with one of our larger telescopes last week, including mucking about with the iPhone app that hooks up to the mount's WiFi. I even took it up to the dark sky site for a few test shots using my DSLR and an Orion Starshoot 5MP colour CCD. More practice with both would have got much better photos, I'm sure, and the hot weather and full moon pretty much ruined the seeing on my test night. After all that, the initial results did look pretty good. The scope is a monster, and is really cool, albeit with a couple of quirks. I've never really played with a scope of this focal length, and I hope to be able to have another go, particularly as Jupiter gets a bit higher later in the year. My review is here .