Nik271

Very nice image! If you are going to stack then getting a lot of frames ( a few hundred) is more important than lack of compression because you are trying to capture the moment of good seeing, and 8 bit colour is sufficient for the Moon. RAW files are quite slow to record on average camera but JPEGs are smaller and faster. So if you are stacking juts take, say 100 jpegs and stack them in Autorsakkert. Or if you prefer take a short 1-2 min long video and stack the frames.

I'm not familiar with the Klevzov-Cassegrain design, but it looks like it has a biggish central obstruction. The TAL looks more like a general purpose scope, capable of at least some widefield views, whereas the CC is more specialized towards high magnification. The CC will very likely beat the TAL on the Moon, planets globulars and double stars. There are some very good reviews of the GSO CC, to me it looks like the better choice.

Finally I got to see the sun today and I'm testing my new BST Starguider binoviewers with a Skymax 127. There is a group of sunspots east of centre of the disc, a pair of big ones in a north-south orientation and trailing them another group of (three?) small ones aligned east-west. The binoviewers work well on the small Mak, with the supplied 32mm Plossls the solar discs fits entirely in the field of view. I found it very comfortable to observe and an improvement on the cyclops view. Hopefully we'll see more activity soon with the new solar cycle picking up!

In my first days observing I also tried the Flaming Star Nebula in Auriga, with a 130mm Astromaster reflector. I found the correct location, consulted Stellarium again and again but no luck, not even a hint of the nebulosity. I decided it was my light pollution Bortle 5/6. Since then I take all these nice pictures in Stellarium with a pinch of salt, maybe it is possible with a big Dob in deep darkness. No such thing in Oxford. No big Dob either Open clusters on the other hand are great with binoculars and Auriga has three very good ones : M36, 37 and 38, roughly in a line bisecting Alnath and Theta Aurigae. I love looking at them both with binos and a telescope. Have fun with the Celestron binos! I have the same pair for a quick look around. Ideally they are for a tripod but many people, myself included manage to handhold them, especially propped on something, e.g. on a fence post.

For me the highlight of the evening was splitting 32 and 52 Orionis that John suggested in an earlier post. First I bagged 32 Orionis which was easier, I used 9mm eyepiece at the Mak giving 300x and the pair were clearly split in roughly SW-NE direction. With the same magnification I could only get 'elongated egg shape' from 52 Orionis due to unsteady seeing so I went down to 6mm and 450x, crazy magnification but it worked. They were clearly separated at the first diffraction ring in moments of steady seeing. What makes it possible is that both components are of equal magnitude. This was my first 1'' double, very happy! I think I got a hint of Sirius B, north-east of the primary but the heat plumes of the houses were making Sirius a rainbow blob and I was freezing and had trouble keeping still at the eyepiece at that stage so this will be continued on another night. Saturday looks good here!

I have a 127 SW Mak and frankly I don't think converting to 2inch visual back is worth the extra cost in diagonal and eyepieces. The opening at the back is less than 30mm, i.e its optimised for 1 and 1/4 eyepices. Sure you can put 2 inch accessories with adapters but there will be vignetting as people have pointed out already. This only makes sense if you have the gear already, so it does not come at extra cost.

Thanks! You were correct that the thread pitch was slightly off: my focuser only screwed in halfway and then stuck, but its secure enough. With a focuser it's easy to change eyepieces and I can use it as wide field finder/mini-telescope riding on my 180mm Mak.

A well-collimated 200mm Newtonian can be amazing at high magnification. I'm sure many owners will happily confirm that. I have a 180 Mak and I'm very happy with it, it beats my 150mm F5 Newt at high magnification easily. You would need 2x or 3x barlow on the Dob to image at the same image scale as the Mak but the bigger problem I foresee is tracking the planet at this high magnification, especially on a small sensor (which is most planetary cameras). Usually you record a 2-3 minute video which is then stacked, so you would need to be able to keep the object in view for this time which on a Dob may not be so easy. In a perfect optical system aperture rules so a perfect 200mm Dob will just outperform a perfect 180mm Mak but in practice it depends on so many other factors that its impossible to generalise.

Hi SGLs, Does anybody know what is the focal ratio (or the focal distance) of the objective of the Skywatcher 9x50 Raci finder? I have a spare one and think of converting it to a pocket monocular, just for fun, or maybe a future guide scope. The thread for attaching the prism diagonal looks a standard 2inch SCT female thread and I have a small focuser, but would need to know the spacing needed. Nikolay

This looks a quite capable quality telescope which will show a lot. All the objects in the book 'Turn left at Orion' (at least in an old edition I have ) were seen by the authors with a 3 inch (=75mm) telescope. With 90mm yours will do better on the dim stuff and will excel in wide views at low magnifications. Think of the Pleiades, Orion Nebula, Beehive cluster, Andromeda galaxy. Just don't push the magnification too much, you will start to notice every little shake of the mount and perhaps there may be purple fringing on bright objects (chromatic aberration). This is perfectly normal in a scope of this design and if it bothers it can be improved with a filter. Enjoy your new telescope!

And when it finally (sort of) clears it's the fast moving clouds that drive me mad, deliberately spaced out to ruin each 2min exposure

Of the three doubles (Alnitak, Rigel and Mintaka) you mentioned by far the easiest is Mintaka, its companion is almost 1 arcminute away from the primary and should be visible in almost any telescope. Could it be you had dew on the corrector plate of the SCT?

I was also tempted by a gap in the clouds around 9pm but it closed too quickly It seems to be the main feature of observing this winter: chasing brief spells of clear sky. I found the Met Office's detailed weather map of hourly rain and cloud cover a bit more accurate than CO. But most often both of them have been wrong, at least for cloud cover.

It's great when we get clear sky at last, isn't it. Thank you, John for the nice report! Both Alpha Piscium and Gamma Ceti are new to me, I will try to have a look at the next opportunity. I was lucky with the weather too: contrary to the forecast the clouds stayed away until 8pm last night, so I managed almost couple of hours at the scope (180mm Mak). The moon was still up at 6pm and I tried my new BST binoviewers which came with 32mm Plossls. The FOV is a bit narrow at only 48% but I'm quite pleased, much better than cyclops and I hope the binoviewers will counter the floaters I get in high magnification. Everything was very still and fog was rising, a sign that the seeing should be good. And indeed it was great: I looked at Mars and Uranus at x300 and they both looked very crisp. Syrtis Major was visible on Mars and Uranus was a tiny clearly defined disc floating in darkness. No moons visible but still this was my best view ever of Uranus, until now with poor seeing it had just looked like a bloated star. If Herschel could see it like this he could never mistake it for a comet. After dinner and a hair drier treatment of the corrector plate of the Mak it was a quick tour of double starts. No binoviewers this time, just a 9mm Svbony eyepiece giving x300. I tried Delta3 Tauri but the dim companion was invisible. Too ambitious! Something easier: Rigel. There were currents of hot air from the houses so I only got glimpses of clarity among mush, but in those clear moments I saw the companion. Good start! Next was Eta Orionis, hmmm too much hot air again no luck. But Sigma Orionis was a fine view - a string of four stars drifting across the eyepiece. Really Orion is full of double stars. Trapezium next at x300, looks gigantic but I think it's too low in the sky to show me the F and G stars. (I have a lot of light pollution in the south sky where the city centre is). I had better luck with Alnitak: a nice yellow companion south of the white primary. I finished the evening with Iota Cassiopeiae: three perfect airy discs forming an obtuse triangle. What a difference observing near the zenith makes! Note to myself: no ambitious double star observing below 40 degrees altitude! (but what about Sirius then , have to make an exception! ) Its so nice to observe again, let's hope more clear spells are coming! Nik

I have that Olympus. It's good for general use but it has undersized prisms resulting in a square shape of the exit pupil. Essentially 2/Pi of the light gathering (about 60%) compared with a full aperture of 50mm. Still a good overall binocular though, I use it in daytime a lot because it has a wide field of view and it's relatively lightweight. To be fair most of the bins in the £50-£70 price bracket will have undersized prisms to keep the cost and weight down. Nikolay

I have also been very pleased with the images of mine. In the summer I managed to split Zeta Herculis with it. I think the main reason the Mak does so well despite the 34%CO is because of the excellent collimation and ability to hold it well. And spherical mirrors must be much easier to produce to high standard than other more complicated surfaces. So taking the CO into account the 180mm Mak should compare well with a good 120mm APO refractor, but it will be beaten by a 150mm APO on contrast.

Well spotted, indeed it was just 5 seconds. I tried a bit longer first but the stars were trailing. 5 seconds is too short for the dim objects but for star clusters it works fine with stacking.

What is the cheapest set up for (modest) deep sky imaging? Yesterday was cold and clear and after an hour or so of visual the corrector plate of my Mak fogged up. I brought it inside to defog but then the beast warmed up and was almost useless for half an hour before it cooled down again. While waiting I decided to try a quick imaging session of Cassiopeia. Recalling this recent post by Vin I put on a 50mm Yongnuo lens on my camera and shot 20 frames of 5mins secs each from a tripod at Cassiopeia, which I then stacked in DSS. Thus is the result: Considering the cost of the gear I'm happy how it turned out. I can clearly see the ET cluster The lens looks OK in the centre but there is vignetting and coma at the edges. I should have taken flats. This got me thinking how a little budget gear can go a long way: a basic camera (I used EOS 250D but I'm sure a 10 year old camera would have performed similarly), lens (£50 Chinese Canon clone) and tripod (£20 amazon basics) and the sky is yours! Clear skies! Nikolay

Hi Doug, Polaris B should look slightly blue and relatively easy to spot with 8SE. Here is a photo I took recently with a 180mm Mak which I think shows the color well. (Polaris A itself is blown out, should be tighter in the eyepiece). I don't think there is any other star nearby to confuse it with. Nikolay

Right, this proves that 34% is the best possible, and in some situations of long back focus distance it may be worse than this because the light cone may be further clipped by the primary or secondary baffles 34% is basically the same as a C8 SCT, that's disappointing.

yes! Reading up on this I realized that for an accurate result I should not be defocusing by moving the primary but by moving the sensor/eyepiece by equal amounts in and out of focus to compare. Some clear spells are forecast tonight, to be continued... Nikolay

I was testing the central obstruction of my 180mm Mak this morning and the Moon was so inviting that I took a short video on a whim. This is my first time processing a wide frame video and I'm pleased how it came out. Pipp and Autostakkert really know their job. The seeing was mediocre, but I'm happy to just be able to observe and image anything other than clouds

I spotted an opening in the clouds this morning and took a quick shot at defocused Polaris. This was taken with the Skymax 180 and a DSLR attached to the 2' visual back (no diagonal). I should have defocused more because the edges are quite fuzzy with the diffraction rings and its hard to see where the field stop is. Clouds arrived before I can experiment more, but already we can see that the central obstruction is close to 1/3 of the diameter. As a bonus I shot an image of Polaris and companion, it's easy because they don't move and can use longish exposures without any tracking There is some better weather predicted for the weekend, I will experiment more to nail this down. As I was focusing in and out it seemed that inside focus and outside focus diffraction patterns looked slightly different, I don't know if this is normal for Maks or just my scope. Nikolay

Indeed, beyond 10x magnification it's a good idea to support the bins somehow, I tend to use a monopod but apparently even a kitchen broom has been known to work As for getting a stiff neck the only solution for me is to use a lounge chair. In the summer I would just lie down on the grass but obviously not a option for winter. Some high end big binoculars also come with 45% diagonals to make it easier when looking high, but these tend to cost more than telescopes. You could try pointing the spotting scope or bins at the Orion nebula. It's never more than 31 degrees above horizon in the UK so the bins will be reasonably close to horizontal for comfortable viewing if you can support them somehow.

I have seen Neptune from central London in 15x70 bins but it was faint and I really needed to know where to look. The key is to look while it is as high as possible in the southern sky, so sometime between 5pm and 6pm for January. I found that the asterism of the three stars of Psi Aquarii helps to find the general area, see the attached Stellarium picture. It is quite bluish once you see it, so you can't mistake it for anything else. Good luck hunting!