Whistlin Bob

Hi Mihai- glad to hear what a good time you're having with your 130. If you're enjoying that, then a larger dob will really do it for you... Have you considered a second hand purchase? Most amateurs seen to take good care of their equipment, and with a dob, unless it's mistreated, there isn't a lot to go wrong. I was in your position a couple of years ago and eventually opted for a 3rd hand (at least) truss 14" Orion USA that I found on Astro Buy and Sell with a few extra bits for £800. I was able to check it out before purchase and it has paid me back many times over in fabulous views and awesome sessions. At my Bortle 5 home it blows my 200p out of the water, at a dark site (sadly only a few trips in that time) it is a wonder. It's needed a bit of maintenance but it has been a fantastic purchase. With the experience you already have you'll know what to look for and if you're patient you're sure to find a similar (if not better) bargain.

Very nice- lots of detail on the outer edge of the glob and nicely balanced and saturated colours. The core is a little blown out though. You might find it better to use masked stretch instead of histogram transformation in PI and also try and hold the top of the curves down when your adjusting in PS.

+1 for this. Worked a treat for me.

That's a lovely shot Rodd- I really like your description of what you were trying to achieve as well, that familiar feeling of being at the eyepiece and trying to construct an image from the grey wisps that you perceive with hints coming and going in the seeing. I think it's so important to remember that and not get lost in the technical details which is so easy to do. Thanks for sharing.

@Moonshane might have closed the thread by completely nailing it with his answer. I use a 14” dob and with a mask it can split down to about 1 arc second, but the results aren't especially pretty. However, I quite like watching the stars float across the fov, separate as they approach the axis and then merge again when they've passed it. I keep hearing about how good refractors are at this, and how nice the views are. Trying not to think about it as like @bomberbaz I'm trying to remove the direct access that astronomy seems to have to my bank account.

I'd have to give a +1 for @paul mc c's advice. I fell in love with visual first then for into AP. When I started imaging I really missed it, so having a dob enabled me to do both. I also find that imaging often involves solving lots of technical problems, a manual dob and the beauty of the night sky is just what I need after setting up an imaging run. A new dob would be a great thing, but there are also loads of terrific second hand bargains floating about as well, especially for the 200p model, plus the Bresser models seem to be really well thought of these days. You'll probably want a few quid on top of the scope purchase for EPs, some finder enhancement (RDF, RACI- I use both) and something to sit on.

Oh no! This is really surprising- the measured difference in focal length seems a slam dunk in demonstrating CA. I really thought the trip to France would solve the problem. How can they possibly have come to the conclusion that it's all fine? I would assume that if they're that confident it's a 'fine example' then they'll be happy to swap it for another one, as this one would still have a strong value as a proven and tested scope.

I think this comes down to your preference of Newtonian Vs Refractor- I know the 130pds is a very fine scope for AP from personal experience. 72ed owners are very positive about their scope as well. Both are light, so the mount requirements aren't too bad. The 130 will need collimating from time to time, will want a coma corrector and will give you diffraction spikes which are a bit marmite. OTOH it has more aperture and focal length. The 72 will want a flattener but it's almost totally maintenance free. Either way you'll have a good astrograph.

The Baader zoom is quite expensive compared to some of the competition so I can understand why you really want to do your homework on it. I was in a fortunate position where I was able to borrow one (thanks @Ken82), and it took me about ten minutes of using it to have me scurrrying to Flo to place an order. So if you can go to a club and have a look through one this will give you a better impression. My view is that the narrow fov at 24mm is a bit annoying so you'll want a better ep for widefield, and likewise down at the bottom end a dedicated 4 or 6 mm will show planets and split tight doubles much more effectively, but in-between these ranges the Baader is excellent and so flexible. My current EPs are 4, 7, 8-24 and 30. I reckon the Baader is in the scope for around 50% of the time. PS: I personally don't bother much with the dedicated Barlow though.

Can I be another +1 on the Baader zoom suggestion? At worst you could go for the one @bomberbaz has suggested, use it whilst you build up a 2nd hand collection and then sell it on at no loss. More likely you would find the convenience makes it the weapon of choice for general mid range viewing and star hopping, only swapping out for widefield (for which it isn't great) or higher mag when you have something that really justifies it. For many targets it's a superb choice and so easy to get just the right level of magnification.

I do use a Corrected Image and now and again I briefly go the wrong way when swapping between finder and eyepiece but it's not a problem at all- more just momentary forgetfulness. I used a straight through finder for a couple of years on my 200p. I found the addition of a quikfinder to be better than the both eyes open method anyway and when I switched to a RACI my only regret was that I hadn't done it sooner- used in combination with SkySafari I find I can start hop with certainty to almost anything quite quickly in my Bortle 5 skies. When I upgraded to a 14" I moved the 2 finders to the new scope and wouldn't be without them now. Other people get by fine with different arrangements, but for me it's absolutely the way to go.

I'm using the SW 0.9x. It has performed very well for me and has me imaging at f4.5 which is pretty good*. I went from DSLR to mono at Christmas, but the DSLR performed well on this scope. In the pictures that's a Canon 550d with a cooling box on it. * I have started getting reflections on very bright stars since I switched to the mono camera. Culprit not yet identified, but the cc is one of the suspects! (as it is no longer covered by a filter).

Here are my two babies- the mighty 130pds (and @Anthony1979- properly collimated and fitted with a coma corrector it's a giant killer of a scope). Then there's my 200p- bought from another member on this site and all about function not form. I have sorted the cabling out a bit since this was taken. 😬 Both shown with an image they've given me.

You're right @Ken82- I am having the same challenge with the Ha. To respond to the OP I went from OSC to Mono at Christmas (Canon 600d to ASI1600mm) and my experience under Bortle 5 skies has been that Mono is at least as quick as OSC to gather a similar set of data. When I was experimenting to start with on LRGB I used an IDAS D2 filter because this had been massively helpful on my Canon (to the point that when they fitted LED lights on my street I feared I may have to give up until that filter saved the day), but it did not seem to help at all on the Mono and I now just shoot with the LRGB filters in the wheel. I use ZWO filters which seem to be par-focal and I set it running on an APT plan to get all four channels and then cycle round them. It's at least as fast to gather the data this way as it was on the DSLR (although it takes longer to process afterwards) and also frees me to observe whilst its running- that's critical because I remain in love with visual astronomy (I'm just two-timing it sometimes with my imaging rig!!!). The frustration I was sharing with Ken was that in order to bring out star forming regions in galaxies I need to capture an Ha channel as well. To demonstrate below are 2 M81/82 shots- one from last year with the Canon and one from this year with the ZWO. Different scopes were used giving different FOVs but from other shots with scopes it's not the source of the problem. The Canon clearly picked out the Ha regions, the ZWO doesn't unless I add an hour or two of Ha in. Even then I really have to push the data to get the same effect. For some reason the second picture has compressed badly, but hopefully you can see the point about the Ha regions. Both images are around 2.5 hours of data, and I would say that except for that and the processing time, there is no other advantage to the OSC.

I'm a little horrified reading this. I think we all probably dream of having one of these beautiful scopes and being freed of the flaws that go with lesser equipment (like mine!!!) Takahashi make a big deal about the excellence of their products and some very strong claims about its capability. I really hope that given the cost of these and the efforts you've gone to to diagnose the problem, they do the business and return the scope working as promised.

This one’s been in my camera for a few days- I took it last Tuesday. It’s made of a mosaic of nine panels- each one the best 5% of frames from a 30 second avi. This was a bit tricky to get- it was only just dark enough, I was running out of time before it dropped below the hedge and the seeing was terrible so this isn’t as sharp as I’d like. Still quite pleased to have got it though. Working version showing panels: Completed version:

No worries @John- feels on topic to me 👍 @markse68 It's definitely worth persisting with- it almost feels ethereal to me- these faint wisps over such large distances. Very much agree with John's advice, my magnification last night was at x41 and I could only see individual components in any view.

Just a wonderful image Neil

Another online club meeting last night- a few of us decided to rejoin to continue the fun for an online observing session around ten. Had the 14" out as the forecast looked good and no work today Before joining the others@EmuStardust and I tried splitting a few doubles that were emerging in the twilight. It's funny how your observing develops- doubles didn't really interest me much to start with, but as time has gone on (and inspired by reports here) I've become a little addicted to it. I've found with my gear an aperture mask and (if the seeing will take it) really high magnification (470x last night) works well. Epsilon Lyra: you could drive a bus through there! Izar: Ok more like a road bike (with skinny tyres) but still a nice clear split. Next spent a bit of time setting up an imaging run, then rejoined the club online call on audio and we tried to look at the same features on the moon. As per @John's report the seeing was superb. My highlights were: Lunar X- my first observation. Lunar V- likewise! Walther- spectacular shadow reaching from central peak and picking out features on the crater floor. Ptolemaeus- wow! Just perfectly placed with the crater rim picked out as a shadow across the crater floor. I spent ages on this trying to imagine the sight at the edge of the shadow as the sun crested the 2.5km high ridge above the crater floor. Reading today that the crater is close to 100 miles wide it isn't quite as I imagined. I suspect for 95% of the lunar day this crater is a bit meh to observe- but so perfectly placed tonight with all sorts of textures and features in the floor it was an awesome sight. Ok so now it was darkish, time to go deep space... M13- familiar, but a wonder every time. Propeller visible. ZetaHerc- split came and went in the seeing, but pretty clear at times. Credit card split, not road bike. M81 Central shape, hazy outlying areas M82 a sleek line, some mottling despite proximity to the moon. Now Cygnus was over the rooftops to the east. Time for a summer target feast: Full veil complex in oiii & 30mm. Lovely view, witches broom much the brighter bit, wonderful to have it back. Crescent nebula- yes! First sight!!! Faint but just visible in oiii. Only really sure because of the keystone asterism framing the wisp. M27 dumbbell- in Baader zoom and Oiii filter. Apple core shape prominent with fainter view of the outer lobes. M57 the ring - very bright in oiii, still easily visible with no filter. M71- quite faint but pleasing M56- very nice- quite faint but with even distribution. Ok- now 2am and only 2 of us left so one last object and the sky is now darkest around Ursa Major. M51- spiral arms!!! Yes! Drifting in and out of perception and requiring AV but a very fine view. So- packed up the dob and the imaging rig and was just locking up and about to go to bed when Jupiter popped round the side of the house and said "You don't want to do that!" Quickly grabbed the 8 inch: Jupiter- 4 moons and stripes oh yeah!!! Couldn't make out much detail with it being so low in the sky, but great to see it again. Saturn- My log says "& Titan" but looking at Sky Safari now I think it was more likely to be Iapetus. I couldn't see the Cassini division but there was a hint of banding. Wow- one of those super awesome sessions that come along so rarely. A real pleasure and such a range of stuff seen. Best not plan anything too demanding today!

It wasn't easy! It never is...

Thanks for sharing! I have always struggled to star hop from charts. Then, a few years ago, I purchased Sky Safari which allows me to precisely simulate both the eyepiece and finder views on my phone. When using it I can confidently hop to anything my scope will show me. Without it I'm pretty much lost!!!! Would very much recommend it...

Wasn't meant to observe as I'm still knackered from Friday's very late night. However, couldn't resist a little time with the 200p when I saw the conditions as I was locking up. There's a lot to be said for summer observing- it's not very dark but just sat out in complete silence, hatless and gloveless splitting doubles and checking out globs. From my log: Dbl dbl- easy split, seeing is ok M13 nice ep filler in 7mm Arcturus- lovely fat gold with glary spikes Izar- tricky, but split definitely there Algieba- crisp wide easy separation similar colours, nice and sharp Zeta Herc- no split tonight- some elongation Leo triplet- very faint but I can see the Messier pair in 30mm M5 fine view in both 30mm and 7mm. IC4665 pretty little cluster to finish in 30mm Albireo- alright- now I'll finish. Beautiful colours.

Thank you very much everyone for trying to help me understand this topic. I've had a go at the maths of this and tried to estimate how much aperture is illuminating each square arcsecond of sky that the camera is imaging- although not all sure I have it right (may just be demonstrating that I haven't followed this properly!!!). Aperture FL Pixel Size ArcSec/Pixel ArcSec2/Px Area in mm2 mm2 / ArcSec2 200 900 3.8 0.87 0.76 125664.00 166024.57 130 585 3.8 1.33 1.77 53093.04 30014.72 I've taken the characteristics of the scope/cc/cameras that I'm using. The column ArcSec2 is meant to be the area of sky each pixel is covering and the Area in mm2 is the area of the mirror, ignoring the central obstruction which is assumed to be proportional for the 2 f5 scopes I'm considering. The final column is then area per square arcsecond arriving on that pixel which is showing a massive advantage for the 200mm scope. I'm then looking at @tooth_dr's very helpful images (which is just the sort of experiment that I was lamenting not having done)- I think the 250mm is better, but nowhere near the extent the numbers above would suggest. I appreciate that they are processed, which probably hides quite a bit, but it really shows that improvements are marginal...

Thanks for the input. I can see there's a maths answer brewing here, which should give me something firmer to use. One for the morning I think!

Thanks @vlaiv- really helpful!