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Dobsonian Scope with Tube Rings?

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I'm still looking for a second scope and a dob 4.5 or 6 inch fits the bill. But I see what I think (at least for me) is a big flaw in most of the smaller dobs supplied in the UK: They are mounted directly from the scope tube rather than tube rings. This means that at some altitude and azmuth positions they can be very awkward to see through and even more awkward to line up with the finder. I notice that Orion (US) seems to be the only dobsonian manufacturer who sensibly mount som of their smaller Dobs on rings which has an enormous advantage.....you can twist the scope so that the eyepiece is in the most comfortable position for a given object.

Trouble is, Orion scopes (presumably because of US to UK import duty and VAT) are incredibly expensive compared with Skywatcher equivalents. I have tried the SW 130p Heritage and with apologies to its fans hated it, finding the flex tubes stiff and the whole construction extremely flimsy (The one I ordered and sent back had broken at the top end and the base had gouge marks all over it). Does anyone know whether you can adapt Skywatcher or other Dobs, even the smaller ones, so that you can mount the tube on rings?

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Is this what you mean? http://www.orionopti...onianmount.html

Mike

Yup, that's the kind of thing. But of course these very simple bits of hard plastic and mounts are outrageously overpriced and add between £165 and a whopping £500+ to the cost of the scope, and they do not supply rings/mounts for smaller dobs. The (US not UK) Orion shops and associated suppliers here do sell smaller Dobs with rings already attached - example: http://www.scsastro.co.uk/catalogue/orion-starblast-6-telescope.htm

But they are at a huge premium over equivalent sized Dobs from Skywatcher, though in this case it is probably not the rings themselves that add to the price but Orion (US) scopes being generally more expensive for reasons stated in my first post.

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....An Orion Star Blast Dobsonian costs around $299 in the US which is roughly £190. The cheapest price in the UK I can find is £299 which is $470 !!!

That's a difference of £110 or $170. Allowing for the sales tax difference (5% US and 20% UK) there is still a big margin. As always, UK prices are routinely higher for almost everything than US equivalents, and it cannot be explained by "import duties" or just tax since it is a global market. In the case of astro accessories the UK market is scandalously over-priced, but enthusiasts don't seem to mind forking out ridiculous amounts for a tiny little bit of plastic (T ring for example).

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I use a big Dob and don't find there's an issue. I suppose that when the smaller ones are looking low the EP would be better on top?

Would raising the scope help?

Olly

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Trouble is, Orion scopes (presumably because of US to UK import duty and VAT) are incredibly expensive compared with Skywatcher equivalents. I have tried the SW 130p Heritage and with apologies to its fans hated it, finding the flex tubes stiff and the whole construction extremely flimsy (The one I ordered and sent back had broken at the top end and the base had gouge marks all over it). Does anyone know whether you can adapt Skywatcher or other Dobs, even the smaller ones, so that you can mount the tube on rings?

I wonder if you have perhaps confused Orion (US) with Orion Optics UK, an easy mistake to make for obvious reasons. These are two different companies and have nothing to do with each other.

The Orion (US) sells the same sort of Chinese scopes as everyone else (though sometimes in prettier colours).

Orion Optics UK does not. Their scopes are of considerably higher quality and I believe they are assembled in the UK (if one considers that to be of importance). They are more expensive than Orion US/SW et al because they are better. You are correct that Orion UK's dobson mounts are of an unusual design, an all-aluminium construction with tube rings. The mounts can be bought separately by the way.

HTH

Steve

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Hm, I didn't answer the second part of your question properly.

If you want to have the Orion UK dobson mount but don't want to pay for their quality scopes you can buy a mount from them here and then a cheap OTA like for example this one. I see no reason that the tube outer dimensions wouldn't be close enough for this to work, but I would check to be sure.

That would land you at about £355 as opposed to buying the corresponding scope with the same mount from Orion Optics UK which would cost about £480. If I read the prices right, but something along those lines... personally I would save up and get the Orion UK scope instead. Either that or live with the standard Chinese dobson mounts that SW, Orion US or GSO offers.

Steve

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Yes Steve I'm aware that Orion UK is different from Orion US. I was referring to Orion US dobsonians called Star Blasters. We also discussed the UK Orion's addon mounts and rings which fit any dobsonian scopes from 150mm up to around 400mm. The US Orion's Star Blaster 6 comes with rings already attached and the mount afixed to the rings, so you can rotate that scope to get a more comfortable angle of viewing, whereas most other makes of Dobs (whether UK or US supplied) generally come with a fixed eyepiece position because the tube cannot be rotated.

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Yes Steve I'm aware that Orion UK is different from Orion US. I was referring to Orion US dobsonians called Star Blasters. We also discussed the UK Orion's addon mounts and rings which fit any dobsonian scopes from 150mm up to around 400mm. The US Orion's Star Blaster 6 comes with rings already attached and the mount afixed to the rings, so you can rotate that scope to get a more comfortable angle of viewing, whereas most other makes of Dobs (whether UK or US supplied) generally come with a fixed eyepiece position because the tube cannot be rotated.

Ok, sorry. I thought you had them mixed up since you said that "Orion scopes (presumably because of US to UK import duty and VAT) are incredibly expensive compared with Skywatcher equivalents" which they are not, if we are talking about Orion US scopes.

Steve

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Steve, my last message just crossed with your new one! Yes I understand all that. I actually like the US Orion scopes (especially the solid tube ones rather than the flextube SW ones), as the construction looks very robust. I don't know whether they are similar optically though. I also mentioned the UK Orion's addon rings but they are very expensive and I'd probably swallow the US Orion's package price instead, though I'm inclined to get a cheap and cheerful small Dob for now just to see if I can cope with all that "pushing and shoving!"

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Orion US Star Blaster 6 inch with rings (both long and short FL versions) are £309 here http://www.scsastro.co.uk/catalogue/orion-skyquest-xt6-classic.htm

The Skywatcher 6 inch Dob, sold more commonly in the UK and with out rings is much less: £210 here: http://www.wexphotographic.com/buy-sky-watcher-skyliner-150-dobsonian-telescope/p10564

So the US Orion version is much more expensive, and they are both the "classic 150p" scopes. There might be some variation at other shops but I can't find the Orion for less than £299.

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Ok. Optically there would be no difference between the SW and Orion US scopes, mirrors are probably from the same factory.

Any particular reason you want the StarBlast 6 rather than the Orion XT6 (or SW Skyliner 150, same thing)?

Steve

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Oops not quite right. The classic Orion 6 inch is long and without rings. It's the shorter one that does have rings.

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Ok. Optically there would be no difference between the SW and Orion US scopes, mirrors are probably from the same factory.

Any particular reason you want the StarBlast 6 rather than the Orion XT6 (or SW Skyliner 150, same thing)?

Steve

Post crossed again !! I think the grey/black Orion one looks nicer, and I believe their bases/mounts are textured and a bit stonger as against the SW wood chip and melamine mount.

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Orion US Star Blaster 6 inch with rings (both long and short FL versions) are £309 here http://www.scsastro....xt6-classic.htm

The Skywatcher 6 inch Dob, sold more commonly in the UK and with out rings is much less: £210 here: http://www.wexphotog...elescope/p10564

So the US Orion version is much more expensive, and they are both the "classic 150p" scopes. There might be some variation at other shops but I can't find the Orion for less than £299.

That's actually a Skyquest XT6 you linked to, not the StarBlast. But that aside, it's weirdly expensive yes, but you can get around that by buying them from Germany where the SW and Orion are the same price (as they should be it's the same scope pretty much).

Orion SkyQuest XT6 cost 279 Euro (£238)

SW 150 Skyliner also cost 279 Euro (£238)

Steve

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Lol. I think we have entangled ourselves in a feedback loop of crossposts. I shall retire and return later :laugh:

Steve

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Yes we can't keep crossing like this. Thanks for that link. I'll investigate the German one and yes a much better price. Thanks!

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Thanks to you Steve, I'm a cusp away from ordering the Ringed Orion Short Tube at that German price, but....I wonder whether the longer FL one without the rings is a better scope for all round watching. Ah...decisions decisions....then again...that 8 incher looks rather attractive too.......resist, resist!!

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It's actually available from Telskop-Service even cheaper (for 10 euro less): Orion XT6

FWIW I have bought things from both these vendors and found them agreeable. They speak English, respond to inquires and ship promptly when in stock.

Steve

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Thanks to you Steve, I'm a cusp away from ordering the Ringed Orion Short Tube at that German price, but....I wonder whether the longer FL one without the rings is a better scope for all round watching. Ah...decisions decisions....then again...that 8 incher looks rather attractive too.......resist, resist!!

I think we are still semi-crossposting :laugh:

I would go for one of the 1200mm scopes if I were you. At F/8 they are a little less sensitive to collimation and less picky about eyepieces than the F/5 one. Depends on what you prefer to observe of course, the slower scopes preferable for solar system objects and such, the faster scope with a wider view better for DSO's. But for an allrounder I would go with the F/8 XT6. Others may feel differently.

HTH

Steve

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Resist the aperture fever! I think the 6" cheap dobs are the most bang for the buck you can get. I used to have the SW one.

Of course the 8" is better but when you decide on it you will start to think that the 10" isn't THAT much more expensive... and... you end up sitting in your sofa, staring at the 18" shower cabin in your livingroom, wondering what the heck went wrong. :smiley:

Steve

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.. you end up sitting in your sofa, staring at the 18" shower cabin in your livingroom, wondering what the heck went wrong. :smiley:

Steve

Excellent simile and imagary!

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I use a 10" dob (same length / height as the 6" and 8" versions) and I have never felt the slightest inclination to rotate the tube to alter the eyepiece position. The slightly up angled positioning is just right and since it moves in altaz the eyepiece is always in a convenient position.

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I use a 10" dob (same length / height as the 6" and 8" versions) and I have never felt the slightest inclination to rotate the tube to alter the eyepiece position. The slightly up angled positioning is just right and since it moves in altaz the eyepiece is always in a convenient position.

That question got lost in the thread's chatter so far. But I agree with this. I have never had any problem with dob focuser/eyepiece positions. Quite the contrary, its GEM that gives me rotational problems.

Steve

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. I have never had any problem with dob focuser/eyepiece positions. Quite the contrary, its GEM that gives me rotational problems.

I've found with my GEM that if I mount the tube such that the eyepiece is directly opposite the dovetail mounting to the GEM, that the eyepiece very rarely gets into a position that is difficult to use. The only place that it gets odd is between zenith and pole.

I have a 6" f5 Meade newt that I must get around to putting into a decent dob mount at some point, as it's not getting used much at the moment. It's not being sold on yet as I have hopes of using it for videoastronomy at some point, whenever I get around to that..

Regarding the OP, once you know what orientations you are comfortable with when using a Dobsonian mount, it shouldn't be that hard to reattach the cheaper scopes at the correct orientation. Most of the cheaper scopes are often "improved" by their owners with little touches like these :)

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