AlexB67

Thank you, looks like provided it is fitted with the base plate ( not clear from that ) it does indeed fit in the gap, I imagine it would be fitted that way, and I see nothing overhanging the rim at the top, so that looks  promising

Hello,

Can anyone confirm if they fitted a telrad to the 10 inch skywatcher flextube Dobsonian ?  The top part of the OTA that slides out is just around 18cm long between the white rims that extrude out from the ATO. Info on the net suggests the base plate is just under this length, so does it fit or is it just a little too long ?  I'd definitely get a Rigel if I cannot fit it to the top part of the OTA, but I get the feeling it will just fit, it almost looks too good to be true, but it is almost as if they made it so that this accessory would fit perfectly in the gap that is there , but I rather know in advance before I pick it up and buy. 

My second question, with the finder scope as well as telrad, any balance issues on this scope ? since it is fairly heavy item. I don't have any heavy eyepieces at this time but could see it may be an issue if I added much more, but I suppose can be modded to cure that. 

Many thanks.

5'10" with 12" FlexTube and 5" frac. I can view zenith comfortably without a stool or cuban heels.

Russell

Hi Russell, can you tell what you made the shroud out of for the middle bit ( behind the flextubes ) seems from the picture it just slides in an out with it nicely, looks neat

Another excellent write up by Qualia.   I wonder would it be worth while adding a sketch for M13 ?  For beginners this is probably the most often common starter object. How dare I make a suggestion to such a masterwork.

I think this leaves us with the GSO options - apparently they're as good as the Sky-watcher - if not better. 

This has been asked quite a bit recently, plenty threads in the forum on said topic. The way I see it,  not from experience but listening carefully, it is a bit of horses for courses really, not much in it,  Orion optics UK more expensive club aside   they all have some strengths and weaknesses.  All these companies are in competition with these mass produced scopes, if one was significantly better value than the other, one of them would stop selling such a model quite quickly I would think. I also remember as a ready to go scope and minimal modding  to start with I heard it said the SW comes out better than most IIRC.

I think the solid tube Skywatcher 12" went out of production a couple of years back. Shame because that would be my preference if I was looking for a 12" dob right now. It was less expensive than the Flextube is too.

I think it is a very valid point, the extra cost, had space not been a concern for car transport I'd go for a solid, the price difference in appreciable and the OTA is that little bit heavier, plus you have to slide it in and out every time, no big deal to me. Collimation is arguably not quite as stable, though form reading around opinions on that seem to vary on how much of a difference that makes, but given that for a 10 inch or above I expect in most cases be it sold or flex, the primary will need a tweak for every session more or less anyway.

I suppose the moral of the story is  when and if the flextube design is worth that extra investment. In my case it undoubtedly was because of the aforementioned, but this may not the case for everyone.

Is that packaging round the OTA what came with the scope originally?  Although not quite as big as that monster I was wondering the safest way to transport a SW Skyliner 200P about in the car for taking it to dark site places.

Yes that foam is the packing that comes with it, same with mine, should be handy.  I can use that if I wanted to as well, with the solid tube I would not be able to as it would be too long for the back seat in my case. I made all the measurement of my car and the scope before deciding purchase.  I know I can even put the OTA upright on the backseat, it would leave 5 cm and tighten it perhaps with safety belt or something else for longer holiday for more efficient packing, with the solid tube I would not have those options.  if you have a  bigger car the same would apply to the 12 inch flex I guess, economies of scale as it were  .  If you got a truck and fork lift for around the garden, just  go and buy that 50 inch

FWIW. I could fit a 10 inch solid tube just on the back seat of my KA, but it would not roll all the way back, as the back seat narrows and it would not sit well. I think it is easy to underestimate how easy and well you can pack these things so you do not end up denting the OTA during transport and leave room for nothing else. I could even squeeze a 12 inch solid  tube OTA if I put the rear and left front seat forward, but again the packing and protection would leave much to be desired and leave no spare room for much else at all. If planning  on going to a dark site on a regular basis or even a small trip away it is worth considering these things carefully. It is the main reason I settled for a 10 inch flextube in the end, in spite of the fact it costs more. 

All in all, I think that  borderline when a scope is that little bit too big and cumbersome, for me anyway to carry or to get it in a car would quickly result in me using the smaller scope more often, bringing that instead. As is often said, in many ways, the best scope is the one you'll use most often

many people spend hours on the internet looking at bits of fluff.

One reason for the bigger scope and upgrades, not to expect to see more hubble type images, but to find more and smaller fluff under the sofa that is fainter    

truly excellent stuff, what more can I say  

Hmmm... I booted my obsy computer in early August when I put the stuff back on the balcony. Hasn't been off or rebooted since, hasn't lost a session or part thereof, hasn't shown any hickups of any kind. I never did understand the "windows needs constant reboots" doctrine. The days of blue screens and reboots are over and have been since the introduction of Windows 7.

/per

I;d have to say I agree with you, this a bit of old adage in many cases, as far as I am concerned that has long gone for most things as far as the OS is concerned. I can't recall the last time I had a blue screen death or an OS  crash .... years. On the other side of the coin for heavy 3D stuff with DirectX and windows optimised drivers, when it comes to games, Linux has still a long way to go to compete with the Open source GPU drivers and speeds  that OpenGL  and also OpenCL implementations can provide in comparison ... in many cases anyway.

I do recall the old days however do when I used Linux in a more serious fashion,  on occasion rebooting Linux servers with an uptime of 300+ days, and the only reason they needed rebooting had nothing to do with the fact they had crashed, so in that sense I recall it be excellent, but IMHO windows 7 is a decent OS these days too   

Yes, I think Moore's Law applies to software, too  Computing power might double every eighteen months, but software bloats to consume most of the additional resources.  Total functionality doesn't grow that much at all

James

So often true, Signed and rubber stamped

Guilty as charged, I'm afraid

I did actually start out on UNIX using something other than vi, but I can't recall what it was off the top of my head.  Then I got into uEmacs, but when I left university I was working on a large range of different UNIX boxes and vi was the only editor guaranteed to be present on all of them so that's what I used and I have done so for the last 25 years.  Now vim does useful stuff such as syntax highlighting I've not seen a compelling reason to change

I don't know how much of a following Emacs still has.  I did know people at university (this was back in the days of 80x25 terminals, before most people had access to a machine with a GUI) who had emacs set as their login shell.

I recall writing my thesis with  some windows version of vim at the time using ( tex/latex ) on a 286 with 64 kB RAM, it was the only thing light enough I could use from home and could handle a document of that size and compile it to a processed dvi , and it handled it with a breeze. Word perfect or whatever word processors were around even on a 386 would just fall over in those days with documents of that size. Vi was so fast that even doing a search and replace in several hundred pages was instant, I am reminiscing now, but those were the days compared to the grinding of some of the bloatware of today :0)

That may well be at least partially due to the fact that I didn't use the QtDesigner IDE.  I've never really got on very well with IDEs.  Give me half a dozen terminal windows and vi any day

James

I do not use Qt designer, but do use Qt Creator,   (but also a fan of vi  & emacs ). I do not use the form GUI designer part of it and write all my GUI components from the ground up, no dragging things on forms :0) Why, because that way I understand what I have written, especially when it comes to event processing with all the  GUI forms design, drag and drop stuff in Qt designer, I don't learn it properly.  Since I found out too, that once you get stuck with the GUI designers with Qt and it cannot do something, it becomes  a pain hacking around, interfering with auto generated code, it is just not quite as flexible.

I do like Qt Creator as a framework for Qt development because the syntax highlighting and some other constructs work well with it out of the box, though I make sure I also understand the build tree and it is quite flexible adding stuff, linking to other libs etc . At the end I'd probably have it so it does not  depend on Qt Creator, but that should be no big issue from what I can see, it is not like Visual studio in that sense depending on loads files part of the IDE ( i.e. a pain, something I do not like ) .  Qt Creator also works on all the platforms and porting the build tree using it's build in features are also not platform specific.  QT Creator has builds for windows, Mac, and Linux, Android and some other devices I never even bothered checking, ultimately I'll never be coding for the mobile anyway. I think Qt creator is the first IDE I ever used in earnest, mostly I was always a vi/emacs man, but I do think it is very easy to use.  But I do know  that in many cases the old habits of Unix people are ingrained, it is written in their genes to use vi

Thanks Alex. This seems doable actually. Having looked around though the only 12" dobs I could find were flexitube and I am actually after a solid tube. Any idea where to get the 12" Skyliner from?

http://www.telescopehouse.com/acatalog/Skyliner_300P_12__Parabolic_Dobsonian_Telescope.html

They do them at telescope house, though I have no experience buying from them ( but sold out right now, sorry did not spot that ) . I agree, they seem to be hard to find from searches so far.

Emad, Have seen this video ? it gives also a fair idea of the size and weight setting up a 12 inch. Doesn't seem to me he is struggling with it  exactly.

http://www.youtube.com/watch?v=bDY8extsWH8&list=PL89258EB0849037F4&index=9

what linux dist are you using out of curiosity ? Looks like the old style KDE theme I recall from some years ago, always liked that one.

Looks nice James. Seems we are in a similar boat, I started using Qt for my calculator app using Qt/C++.  Many moons ago I used C and never used C++ before in earnest, though often had to read code in it and code little bits, so was I somewhat familiar. Anyway after blowing away the cog webs all the coding came back rather easily and find Qt very nice to work with. 

I think you'll find the window port to be a breeze for the Qt bit anyway,  butdepending what other dependencies you've got on other libs who knows, Qt is not a 100% native desktop integration but works well enough in windows. Not tried a mac port myself, but if need be you got the nice Q_OS_LINUX and Q__OS_WIN AND Q_OS_MAC macros to get out of jail for some specifics if need be. also Qt has its own threads of course so I guess using them if possible to avoid more OS change troubles. I find it to work really well in windows, KDE, Gnome whatever you throw at it, though note some themes can be a bit buggy with GUI layouts spacing sometimes, invariably this is the window manager theme and font handling issue more than a Qt fault I found across various windows managers. You can always force you own theme also  on whatever platform it runs on with style-sheets so it will look the same on all platforms.

God luck with the fun

the difference between f4.9 and f4.7 could be the difference between no coma and lots of coma though.ive never really heard any bad reports of the 12" on eyepieces but lots of the 4.7 so its make your own mind up time

Could it is just the eyepieces some use. If you can afford a big 12 inch you may also have better eyepieces in you arsenal ? Lots of reasons perhaps why such reports may be coming from various sources. I don't ever really recall ever reading that in this forum anyway or some others that I read ( but not registered user).

In the end of the day Coma goes as f ratio^3, there is no hard line but it does grows as the cube ( or the square  depending linear or angular version). Not that I've looked through either mind you except my own at f/5. Not trying to bicker or sound hard headed , but trying to rationalise it. In the end of the day both such systems would actually have a very small field where the coma lies within the diffraction limited field anyway ( I've done the sums on it and can create a few tables if you like).   

Granted, I do not have the experience of the big scopes that you own, that being said, the numbers don't lie, without trying to sound too much like a Mr Gradgrind :0) I find it a bit hard to follow your rationale. Perhaps there is more to it as to why you say that.  I am all ears, or tell me if I am just being pest and being difficult and I'll go away    

Ideally I'd like my 10 inch Newt to be at least f/5 or above really, ( f/6+ inch dreams I have )  but when I think 4.7 or a 4.9 as a hard line it would not stop me buying either way, coma is what it is in Newts, there is always a coma corrector I can think about down the line anyway, not that coma bugs me a lot of the time anyway once I am out there looking up the sky, sure enough,  I do see it in my scope, it is there.

edit: I should have said that my argument assumes a parabolic mirror shape. All of these sky-watcher are afaik, except some of the lower end smaller ones where it may be spherical in which the f ratio cube relationship is not true and the other aberration  rules not even mentioned ( but do exist)  if I recall my formulae correctly without a check .

Orion Optics are wholly made in the UK.

Orion (USA) dobs are made by Synta in China who own and make Skywatcher scopes and Celestron scopes, amongst others.

Orion Optics scopes are much more expensive to buy new than their chinese made equivalents but offer a range of focal lengths, tube and mirror specifications. They are quite reasonable to buy on the used market though and thats how I bought the OO scopes that I've owned including my current 12" F/5.3

You lucky man ,  I saw one of those on ebay time ago, did not have the cash or could have bought it at the time ( it was a 10 inch though ) , but it was sold in no time, only afterwards did I realise what it actually was in terms of optical quality as I learned about mirror specs etc. Now I got the cash I could have bought  it, of course they are nowhere to be found. I could press the buy it now button at FLO if I wanted to buy the 10 inch sky-liner, but gonna keep my eyes open, no rush, you never know what may turn up in the next month or more for that matter.

interesting view, not what I want to hear , saying that the 12 inch is f/4.9, the 10 inch f/4.7, not that much diff with the distortion you get, not exactly a hard line I would say, but the 8 inch it becomes somewhat more appealing at f/5.9.

The reference to Orion scopes is that of Orion Optics UK a completely different company to Orion Telescopes USA with optics in a completely different league.

Ah thank you for clearing that up So the ones they sell in the UK I mean were the ones I was referring to, they are the same optically as the sky-watchers ( they cost much the same ) ?

Imad,

Worth noting that the orion optics dobs have a lighter and more compact mount. Optically they are also favourably reviewed in comparison with the Skywatcher and GSO equivalents.

Generally the flextubes are heavier than solid tubes, but more compact for storage and can be split down for moving.

Jake

I thought that the standard Dobs in sky watcher and Orion had the same optics no ?  I did see some sites offering Orion models to upgrade the mirror IIRC form 1/4 to 1/6 1/8 PV etc. of course it would cost extra so you get what you pay for in both cases ?

I don't own either, but it is often said 10 inch is the kind of comfortable limit that can be easily handled by one person. I suppose a consideration has to be how far you have to carry it around, If 20 meters more in a garden when you observe from different spots in a session ( as I do ) I suppose 12 inch could become a bit of a burden.

If you got a good back and are up to it why not 12 inch, it keeps you warm carrying it around a bit in the cold winter  

Whilst I am not an imager of any kind. A simple way of looking at it is that in photography you have one extra variable under your control to collect light and that is exposure time, it feeds into the above and everything that has already been said. For visual observing you do not have the ability to do that, whatever amount of light falls on the eye depends totally on the aperture or light collecting of the scope, but in AP you can play with both, therefore aperture is less critical in total.