Jump to content

Banner.jpg.b89429c566825f6ab32bcafbada449c9.jpg

10 inch Dob - help me decide (OO vs Skywatcher)


Recommended Posts

An open question to all Skywatcher owners: Have you ever bought a Skywatcher Newtonian telescope (including Dobsonians) and felt that optically it was under performing?

Steve

Yes. I wish I'd waited a little longer and got the OO VX6. Optically it's better, and the design of the mirror cell/clips on the SW150P leads to some horrible diffraction patterns when imaging.

However... others with the same scope don't have my problems, so that alone points towards some inconsistency problems.

I don't think I'll be buying another SW product actually. You get what you pay for, and with SW, you pay so little. SW mounts I'll happily buy, but I'll probably go with OO next time I buy a reflector scope.

Link to comment
Share on other sites

  • Replies 44
  • Created
  • Last Reply
One thing to note with OO is that they were primarily an optics manufacturer, and some of the mechanical quality control was a bit hit and miss on their Newts and Dobs. They are now moving up-market and getting out of the SkyWatcher/ Meade end of the market. Their new VX range has excellent build quality with better components than you would find on a SkyWatcher Newt / Dob such as the mirror and mirror cell, focuser, dob base etc.

So it's important to differentiate between what OO is offering now compared to even a year ago.

John

That's precisely what I was wondering about/hoping to hear, regarding past build quality comments. Thanks. I wouldn't mind having more detail though, if anyone can offer it. What mechanical aspects are better than they used to be, and how? I guess there won't be many people who have bought a new OO recently enough to answer, so I should probably just be grateful for this much info.

Hi

I don't own either of the two scopes mentioned so I will not attempt to convince you either way but I do have a home built (with meade optics) 10" f/4.5 Dob.

I would just like to inform you that collimating is not a big deal and hardly rocket science you will find it pretty easy.

As for observing mine is about 4' (1200mm) long so I do all my observing with it in comfort from an adjustable drum throne.

There is no position the tube can get in that is awkward or uncomfortable I would swear it's the most comfortable scope you can observe with.

As you are slightly taller than me both the scopes you are thinking of should be "just right" for you to observe with exactly the same level of comfort.

Although the secondary of a newtonian does obstruct the primary the loss of light/contrast is not as bad as is widely publicized.

Even my fast f/4.5 still produces very satisfactory Planetary and Lunar views.

Faster newtonians will show some coma that is for sure although if that bothers you there is always the option to get a coma corrector later.

It doesn't bother some people it's a case of suck it and see.

Hope this helps to lessen your worries about collimating, eyepiece comfort....etc

IMO you can't go wrong with either scope

Good luck with your choice and please inform us of your decision.

Regards Steve

That's very helpful, thanks. I had not considered a drummer's stool but it makes a lot of sense. This might be all I need to hear about the physical ergonomics and has reassured me a bit, but if anyone else wishes to say any more on the topic (or has any additional suggestions for things to sit on!) please do. I worried a lot about this aspect because comfort has been one of the things I really liked about my binocular observing setup.

As for collimating, well, we shall see - I can be a clumsy beggar but I hope you are right about it being fairly easy. I suppose I can go and dig out my old 4.5 inch Newtonian to practice on it and get some idea.

I'd like to have some idea of the difference in contrast (as a result of the change in secondary mirror size, or anything else) between an f/6.3 and an f/4.7. There was a post I read earlier today by someone saying (something like) that a 10 inch f/6 dob had been their ideal scope and that they regretted selling it - I felt vindicated to read that but I'd like to hear more detail on why he thought that way. I'll try and find that post again. Mind you, it might be a classic example of confirmation bias (I probably didn't pay as much attention to posts saying something else was their favourite!)

Link to comment
Share on other sites

Yes. I wish I'd waited a little longer and got the OO VX6. Optically it's better, and the design of the mirror cell/clips on the SW150P leads to some horrible diffraction patterns when imaging.

However... others with the same scope don't have my problems, so that alone points towards some inconsistency problems.

I don't think I'll be buying another SW product actually. You get what you pay for, and with SW, you pay so little. SW mounts I'll happily buy, but I'll probably go with OO next time I buy a scope.

Would it be fair to say, though, that you notice this only because you use it for imaging?

Link to comment
Share on other sites

Would it be fair to say, though, that you notice this only because you use it for imaging?

yes, perfectly fair. While viewing I notice none of the abocve mentioned problems. The build quality of the scope is great. The focuser is great.. everything about it is great... until you image with bright stars in the frame then you get the most horrible diffraction patterns.

In all fairness to Synta, the scope isn't marketed as a "astrograph" but then again it's the same mirror cell that's in the 150P DS, and that IS.

Optically, I'm not pleased with it. If I viewed only I would be happy, but that's not the point. Is ignorance bliss?

It's sloppy design of the mirror clips, and because of that I will have to take my scope apart and start hacking away at parts of it trying to repair an error that better design could have avoided.

Like I said. You get what you pay for. Plus.. I think I'd get some satisfaction from buying from a British company as well if I went with OO.. and a North West based company to boot :)

Oh... by the way.

May I just flag up Mike's images taken with a 10 inch SW? They are consistently breathtaking and exposures as deep as that are pretty ungforgiving. I know imaging is not the OP's intention but the images in question do suggest fine optical quality.

Olly

Mike who? Where can I see these images?

Link to comment
Share on other sites

Mike is Yfronto, he uses a 10" SW newt, as does Steve (Steppenwolf).

Tony..

I've just looked at some of Mike's images, and yes, they are stunning. Looks like I have a dodgy one then. Unless the design of the larger SW scopes is different.

Link to comment
Share on other sites

One thing to remember is that the OO dob is hand made to your specifications. You can customise it just about any way you want ........

John

Probably the most compelling argument for choosing the OO : you can have a bespoke telescope. I know that if I ever place the order for the 'planetary' newtonian I keep threatening to buy, then I'll ask OO for the very choice spec I have in mind.

And if you don't need a telescope customised to an unusual spec, why pay the extra?

We all tend to suffer from mission creep when choosing telescopes I'm afraid. Me more than most:o

Link to comment
Share on other sites

yes, perfectly fair. While viewing I notice none of the abocve mentioned problems. The build quality of the scope is great. The focuser is great.. everything about it is great... until you image with bright stars in the frame then you get the most horrible diffraction patterns.

In all fairness to Synta, the scope isn't marketed as a "astrograph" but then again it's the same mirror cell that's in the 150P DS, and that IS.

Optically, I'm not pleased with it. If I viewed only I would be happy, but that's not the point. Is ignorance bliss?

It's sloppy design of the mirror clips, and because of that I will have to take my scope apart and start hacking away at parts of it trying to repair an error that better design could have avoided.

Like I said. You get what you pay for. Plus.. I think I'd get some satisfaction from buying from a British company as well if I went with OO.. and a North West based company to boot :p

There is an American company that makes a CNC 6 point cell that will fit the 150 OTA with few minor mods. Unfortunately it's a bit on the expensive side. :) Here's a photo of the cell in my 150PL with OO mirror.

http://www.opticalsupports.com/mirror_cells.html

John

Link to comment
Share on other sites

Thanks John. I've been reading your thread closely! :)

I don't get any nasty diffraction patterns with my 150P for imaging with a Canon 1000D hung on it. Only nice clean spikes on the brighter stars. I only ever get up to 90sec subs because the mount's unguided, but I have been most impressed with this little scope. Are you sure you haven't over-tightened the mirror locking screws and pinched it?

I still use the 150P for visual use as well and love it but having looked through friends 10", 12" and 16" scopes I want a bit more light to be able to add filters for nebulous objects because I struggle with light pollution. I have already picked out a nice Skyliner 250PX for a visual scope in a couple of months time. Big step up from the 6" and far more portable than the 12" which is important for me. I would go for a 300P flex-tube but can't afford one :p

Link to comment
Share on other sites

I don't get any nasty diffraction patterns with my 150P for imaging with a Canon 1000D hung on it. Only nice clean spikes on the brighter stars. I only ever get up to 90sec subs because the mount's unguided, but I have been most impressed with this little scope. Are you sure you haven't over-tightened the mirror locking screws and pinched it?

Positive. It's not pinched optics. It star tests perfectly.. well as well as can be expected for a scope of this price.. but the rings are perfectly concentric.

It's definitely caused by the mirror retaining clips.

fin.jpg

Link to comment
Share on other sites

Hi Pook,

Yes, those dark triangle diffractions are caused by your primary mirror clips. It is not unique to Skywatcher, all Newtonians (including OO's) that employ mirror clips will show a similar result. Yours are rather more pronounced than I would like, though the image you posted is a little out of focus which would enhance them and they are more noticeable with smaller mirror diameters as the clips cover a larger percentage of the outer diameter. You could remove the clips, round their corners then refit them. That would help. And you can completely eliminate the aberration by cutting a small ring/mask that covers the outer edge of the mirror, including the clips. Some imagers remove their clips completely and use silicon to secure the mirror but that is a bit extreme so I cannot recommend that in your circumstance.

You say you would rather have bought an OO. I cannot tell from your username whether your 150p OTA came from us but if it did I'll happily arrange a full refund so you can spend it at OO :)

HTH,

Steve

Link to comment
Share on other sites

The mirror clips on the SkyWatcher 150 are a bit on the big side, however if they're not too tight and just barely contacting the mirror surface and not putting any presure on it then it shouldn't cause any problems.

Here's a comparison between a SkyWatcher 6" mirror and cell and one that has been upgraded to an Optical Supports CNC 6 point cell which uses silicone to secure the mirror at the three "clip" points.

John

Link to comment
Share on other sites

Hi Pook,

You say you would rather have bought an OO. I cannot tell from your username whether your 150p OTA came from us but if it did I'll happily arrange a full refund so you can spend it at OO :)

HTH,

Steve

Fantastic offer Steve! Unfortunately, I didn't purchase it from FLO. My impatience got the better of me and I got it from somewhere within driving distance. :p

PS: The diffraction spike running fron 11 o'clock to 5 o'clock suggests one of your secondary mirror supports might be twisted. It sometimes happens during collimation but is easily fixed :p

HTH

Yeah... fixed that now.. one vane was not fully end on to the OTA.

The mirror clips on the SkyWatcher 150 are a bit on the big side, however if they're not too tight and just barely contacting the mirror surface and not putting any presure on it then it shouldn't cause any problems.

John

Looking at that... I can shave quite a bit off the SW clips, and round them quite a lot, and still have enough left to secure the mirror I think.

If I have no luck arranging a replacement from the retailer I bought it from (probable) then I'll probably take some power tools to those clips.

Link to comment
Share on other sites

Hi again,

The discussion in this thread has been very helpful. However I have decided, for now, not to decide!

At the moment I feel that, price aside, the OO f/6.3 would be the right telescope for me and that I would, in one way or another, not quite be happy if I bought the f/4.7 Skywatcher. And right now I *almost* feel giddy enough at the prospect of a nice 10 inch Orion Optics Dobsonian to rush ahead and place an order.

But the last thing I want to do is to make the wrong purchase. Especially given the large expense involved. I've made (what I consider in hindsight to be) a bad choice before now, when I bought my too-cheap underpowered EQ-mounted Newtonian, so I don't want to do that again - or to make the opposite knee-jerk reaction of hot-headedly spending too much on something that might not (in the cold light of day) be worth it.

So I'm going to sit on the idea for a couple of months or so and then see if I have changed my mind. In the meantime I'll try to get some binocular observing time in, to appreciate what I already have a bit more, and perhaps even give the 4.5 inch Newt a bit of use (if nothing else I can use it as collimation target-practice).

Thanks again for your advice. If/when I do make a final decision I'll let you know about it!

Link to comment
Share on other sites

Good idea to wait - there is a lot to think about !.

You may well see a good used deal in that time as well - Orion Optics scopes tend to depreciate quite a lot so you may be able to pick up a bargain :)

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. By using this site, you agree to our Terms of Use.