Which Dob ?

[vlebo]

Hi everyone.

Im just trying to get some feedback on a possible scope purchase.

Which of these two would you go for if you where to have this choice

1 The Orion Optics 10" VX with 1/10 pv optics , 10:1 focuser and dob mount for £1244 or

2 VX12 Dob with no optics upgrade with 10:1 focuser and base for £1615

Do you think the 10" with optics upgrade will compensate for the lack of aperture over the 12" 1/6 pv optics or does aperture still rule over optic quality. The 123" is F4 and the 10 "is F4.8

I will be using it for all round viewing ( solar system objects and deep sky ) as I want to stick with one scope.

Thanks

[dweller25]

You would need to be very accurate when collimating the F/4 scope, it has a smaller correct collimation window than the F/4.8 scope, apart from that they would both be great all rounders.

[Stargazer_00]

Is the VX12L in your budget range? It has a much more forgiving F ratio at F5.3

In terms of the P/V effect, I'd like to understand the significance of this myself. The OOUK website would have you believe the difference is immense.

Larger apertures will increase your limiting stellar magnitude.

The increase in P/V will increase the resolution of the images your mirror produces, it wont make dim objects brighter - that is what larger mirrors do, it should just make details crisper.

[dweller25]

@vlebo - forgot to mention the F/4 system will require very good quality eyepieces.

@stargazing00 - I have a 8" 1/10th wave OO Newt and the views are very sharp and contrasty - significantly better than the rather good Skywatcher 8" Newt it replaced - I would not think twice about recommending this option.

[Stargazer_00]

Would you say it like a difference between crt tv and 1080p hd? Or More like the difference between hd ready and 1080p?

[Moonshane]

hi Chris

This question is almost the same as what scope will be better for imaging or visual. The answer to your question really relies upon your preferred types of target I feel.

Scenario 1 - Solar system and double star higher power viewing are the norm with fainter objects secondarily important. Choose the 10".

Scenario 2 - Preference for fainter objects with solar system/double stars secondarily important. Choose 12" scope.

Ideally you should go for the 12" with the upgraded optics of course. I can say that the 12" f4 (I have one) is a lot less cumbersome to move about than the 12" f5 (I had one previously). For f4 you need to include the cost of a coma corrector (£100-£400) at f4.8 not so critical and at f5.3 not required I feel. Top quality eyepieces are not expensive. TV Plossls are top quality eyepieces. Without a Paracorr, my 32mm TV Plossl (and my 26mm Nagler) show lots of coma. My 15mm TV Plossl is much more usable. Both tested on the double cluster.

Personally, I'd never buy a OOUK scope new as there are some genuine bargains on the used market for these scopes, although you have to be patent and quick.

[Scooot]

I went for the 10" because I thought I could manage moving it in and out of the house regularly without too much trouble. Have to draw the line somewhere. Don't know if that's a consideration for you?

[Stargazer_00]

certainly getting the weights and dimensions before purchase is wise. I've a number of weights at home from when I used to think exercise was worthwhile, I use those to gauge if it's manageable or not.

I think 25kg is probably the limit of what I'd carry without thinking I might trip and drop something. Obviously this is different for all, im sure some can manage 40kg without a trouble..

[Moonshane]

not without a sack truck!

[Stargazer_00]

I only consider the distance from my storage shed to the lawn for carrying, which in total is maybe 25 feet, or less.

I could manage more weight possibly but why risk it. you have to imagine the nights when you have to pack up a big giant tube covered in slippering ice, not just the weight I guess.

Anyway before I ramble off topic, the point is to get the dimensions and weights before purchase and mock up something with an approximate weight to ensure you can move it ok.

[Moonshane]

very true and a good point. weight is one thing though, bulk is another.

[Stargazer_00]

I've aways found it's carrying the bases that injures the back, not the OTA. A tube is quite a friendly shape to carry. One hand around the primary and the other arm cradling the tube about 2 thirds up.

The bases are notoriously odd shapes that put the bulk of the weight quite far away from your pivot point putting far greater stresses on your back. I think when I get my next scope (14" still looking good) I'll get a sack truck just for the base.

[Moonshane]

I agree completely about SW bases. I don't use them though

[Paul81]

Hi Vlebo,

I had the same debate myself a few months ago, and in the end settled for the VX10 with 1/10PV optics, 10:1 reduction (on a dob mount). I was seriously torn between the 10" and 12". I ended up getting the 10" as I felt that it was more portable, and had better growth potential down the line - let me explain. My back garden isn't the best for observing, so the 10" being more portable is easier to load into my car and transport to a dark site (my in-laws farm). A dark site is way better than the extra 2" of aperture. Also I felt that although I love visual observing, the camera is far better at picking out detail than the eye, especially with light pollution. So my other reason for getting the 10" was that it has better mounting options (i.e. you can more easily get away without a super mega bucks mount which I suspect you would need for the 12") should I wish to image. Now I am not thinking of hardcore long exposure imaging, I am thinking more like video imaging. Again this yields more than (in my way of thinking anyway) than the 12". I may get a Skywatcher AZEQ6 at some point for video imaging.

I got my VX10 at astrofest for a good discount, OO delivered 3 weeks later. I have to say their customer service was brilliant. The scope itself is also exceptionally well built, is fairly light and the dob base is brilliant - so smooth and solid.

I use TV Ethos eyepieces with it - the OC1 works perfectly fine. If you did use ethos eyepieces then you need a 2" extender to reach focus.

In terms of the views, well I can say nothing but exceptional. The high quality OO optics combined with the Ethos just yields brilliant results. I have looked at a variety of objects, planets, clusters, double starts, nebula and galaxies and I am very pleased. Star fields are ultra immersive.

The scope holds collimation very well, I have adjusted it once (with a cheshire) - all very easy and quick.

I had OO fit an extra finder shoe for a red dot finder. The finder it comes with is a TS one, its ok but I think I will probably upgrade it to something better during the summer break.

Overall, I'd very much recommend the scope - you wont be disappointed, I think the extra price is worth it in my opinion and if you can grab some top notch eyepiece glass to compliment it, then you are in for a treat!

I guess the only issue... damn clouds and this annoying weather (I have managed 5 outings with the VX10 since I got it...)

[Mr Fiery Jack]

MDF, no thanks, OO dob bases are the business. Secondhand OO offer some fantastic bargains. Mine has Hilux coatings and 1/8PV optics upgrade with a strehl of 0.992, all for 350 quid.

[Scooot]

The orion optics base and OTA is very "user friendly" in terms of carrying, and unless I'm only moving it a few yards for some reason, I'll always carry them separately. They store very nicely upright in a corner somewhere as well. I think its a nice size and i never feel like not setting it up because of bulk etc. whether i would with another couple of inches who knows but its worth thinking about. I went to the Astro Fest and saw a 10" standing next to ( I think) a 14" on the Orion Optics stand and my size looked minute in comparison.

In terms of optics I haven't had the opportunity to compare mine (1/10 PV, streyl .992, ) with others but I am very confident the sharp views I get are very good.

So if I was offered a free upgrade to a 12" with lesser optics at f4 I don't think I'd take it after considering the extra bulk etc.

but you're circumstances might be different.

[estwing]

lovin the hi-lux coatings...well looks good in the wooden box!!!!!!

[Scooot]

MDF, no thanks, OO dob bases are the business. Secondhand OO offer some fantastic bargains. Mine has Hilux coatings and 1/8PV optics upgrade with a strehl of 0.992, all for 350 quid.

That's a real bargain, I understand why you're pleased, but you need people like meet me to buy one from new in the first place. If you can get one second hand however its a "no brainer". I don't know if its my imagination but there seems to be a lot of praise from happy owners recently so I wonder if the second hand prices might begin to rise a bit in future.

[John]

I have an OO 12" F/5.3 with Hilux and a 1/8.8th wave PV primary with a strehl rating of .987. Shane has made me a dob base in the style of the OO dob mounts. The whole scope weighs 26kg and the optical tube just 16kg - thats a lot lighter than the Skywatcher / Meade 12" F/5 dobs.

It's a superb scope and, thus far, has performed exceptionally well on lunar, planetary and binary star observing, including revealing Sirius B and the central rille in the lunar Alpine Valley, both firsts for me.

The tube and OO mechanicals are good enough but not exceptional but the optics (OO's strength in my opinion) make the scope very special to me.

F/5.3 means collimation is relatively easy and is maintained well. There is little in the way of coma and the secondary is a fairly modest 21% of the primary diameter. All factors that go to enhancing performance of course.

My OTA is used and cost just £250 (they are over £1K new I think) and the base is really excellent for a similarly low cost (thanks Shane )

[estwing]

...another very happy OO customer...

[John]

...another very happy OO customer...

I'm very impressed with the optics and the mount is excellent. The rest of the bits do their job well enough but I'd have been a little disappointed with them if I'd bought the scope new to be honest.

As Shane says, they are really excellent used buys, absolute bargains in fact

If you were to order one new, I can't see the point in going for 1/6th wave optics though. The whole point about OO is that they can produce great optics so you want to exploit that.

[estwing]

if john nichol is happy to let them coat his work then so i'm i!

[Mr Fiery Jack]

I was a confirmed refractor fan, until I obtained my scope. I thought for 350 quid I could just get the whole aperture thing out of the way and make my money back with the smug satisfaction that my refractors were just that extra cut above...er not so. Maybe its that the Synta scopes I have used were not properly cooled, perhaps they were not collimated, I don't know. What I do know is that my scope throws up fantastic views, as good as, and sometimes far better than my refractors ever did, particularly when observing solar system , Jupiter in particular, I would not have believed it possible. Even now I would be extremely reluctant to sell my scope in case the next year one was not as good. My scope appears to be free of all the horrible imperfections of which I always associated Newtonian scopes with. I am certainly keeping mine, if I had to buy again , god forbid, it would be Orion Optics.

[vlebo]

Thanks everyone.

Some very positive comments about OO dobs and it would seem opting for the better optics would be the way to go and as Moonshane says ideally the 12" with the 1/10 optics would be the one to go for.

I was allowing within my budget the purchase of two more Pentax XW to complete my set , the 7 and 5mm ( I already have the 30 , 20 and 10mm. )

I may go for the 12" with 1/10 optics and try and reduce my outlay by getting just the 7mm XW as seeing conditions generally may mean the 5mm does not get used that often even though I have always wanted to have a comprehensive set of XW's ( i would rather sell a scope than part with a good set of eyepieces , especially XW's )

Decisions , decisions !

[Mr Fiery Jack]

That sounds like a plan, excellent