Guan Sheng OTAs

[matt]

Is it possible to buy a 12" GSO OTA which isn't intended/built to be dob mounted?

I know it's possible to GEM mount the 12" dob but was wondering whether they can be found without the alt bearings sticking out the side. Just as a clean OTA?

It seems to me something GS should consider.

Thanks.

[iceman]

I don't mind the alt-bearings, as it lets me put the 12" back on it's dob base for storage, as well as visual observing (should I choose to).

Visual observing using a 12" on an EQ6 is incredibly frustrating because the EP gets in all sorts of weird spots and you need a step-ladder.

The alt-bearings fit between the rings so there's no real issue the way I use it.

[matt]

Thanks Mike.

Just doing a little thinking out loud. No plan at this stage for a GS purchase.

I'm still mostly enjoying the SCT experience but do sometimes miss the visual quality of a good Newt.

[Dennis]

Hi Matt

Have you had a look at the Orion Optics (UK) series of Newtonians (http://www.orionoptics.co.uk/SPX/spxrange.html)which are available as clean tube assemblies? You know, I might be heading down the same path for my next OTA upgrade some time in 2008?

Cheers

Dennis

[matt]

Very interesting, Dennis. Thanks.

The SPX 300 f5.3 looks very interesting.

[Dennis]

With the current Au $/sterling exchange rate plus shipping costs, I suspect these would be quite expensive to import right now. I’m a little wary of Newts, as I have enjoyed the almost unlimited back focus of the C9.25 and the somewhat lesser amount of the Mewlon 180, and right now I don’t want to fiddle with shifting the primary up the tube etc.

Then there is the focuser position, as Mike mentioned.

Cheers

Dennis

[iceman]

They look great. I'd hate to think how much postage would be. My rings and dovetail cost me 50 pounds for postage on their own!

[iceman]

When's the last time you looked throug an eyepiece anyway, Dennis? ;)

Just kidding :) But for a photographic scope, they look great.

[Dennis]

Hi Mike

:lol: My current tripod will be far too tall for a Newt, as it is optimised for refractors and cassegrainian type ‘scopes, so I guess I would be in for a bit of a shock, having to stand up and peer down the eyepiece!

Cheers

Dennis

[ving]

matty, why not just remove the alt bearings? I did... you are left with 2 small screw size holes on each side which if they really bug you you can just tape over...

[matt]

Thanks for the info, David.

Having never seen a GS OTA 'in the flesh', I was unaware the bearings could be removed.

[ving]

2 bolts either side ... gone.

[rmcpb]

Yep, bit of black gaffer tape over the holes and it looks like a design feature :)

[ving]

tape a picture of kyuor loved ones over the holes :P

[erick]

Matt, ten minutes with a screwdriver or two and the entire OTA will be a pile of bits and pieces! Everything comes apart.:D

[ving]

for what they are they are really quite wonderous :)

[skies2clear]

If you can afford the extra expense, I think this would be a good way to go. Orion Optics (UK) test all of their optics carefully, and you could have confidence that whichever accuracy of optics you purchase (they have various grades), is what you will get. You can't guarantee this with GSO, though many of these optics work very well, there is a chance you could get a less than satisfactory one. You often get what you pay for, but not always,

Cheers
Nick

[gbeal]

I actually like the ability to swap the OTA from GEM to dob as and when required, so even if you remove the bearings, give some thought to a cradle of some style to allow the dob use. Notwithstanding the very learned Dennis, I reckon the humble newt is seriously under-rated, especially from an imaging point of view. Sure the eyepiece will be in some weird spots, but when you are imaging does it really matter?
Try one.

[GTB_an_Owl]

JUST what do you think the ICEINSPACE stickers are for ??

;) :lol: :lol: :lol:

geoff

[ving]

patching up the pool whenit leaks geoff :P


hey matt, werent you getting a mewlon of something?

[matt]

I was asking questions about it, David.:)

[Dennis]

No harm in dreaming...keep the dream alive eh.

Cheers

Dennis

[[1ponders]]

Just be warey when ordering rings for the 12" DSO Dob OTA. If they are anything like the 10" then the standard rings will be too small. Standard rings for a 10" Newt are 285mm, the outer dimensions of a 10" dob is just over 300mm.

[Gargoyle_Steve]

The outside diameter of my 12" GSO's OTA is around 365-370mm, as a guide.

[matt]

Are the mounting rings easy enough to get a hold of?

Would they include the rail or mounting plate?

[peter_4059]

Matt,

I have the 10" GSO and have been through this exercise. I've replaced the loose nuts that hold the alt bearings on to the tube with captive ones so I can remove/replace the bearings without having to reach inside the OTA. I take the bearings off so the tube can be rotated without the bearing fouling on the dovetail but put them back on for storage or if I can't be bothered setting up the GEM.

I bought rings and dovetail from Star Optics to suit the 10". These were sold separately. I assume you can get rings to suit the 12" also.

Peter

[iceman]

Getting rings to suit a 12" is surprisingly difficult. There's nowhere in Australia (that I could find) that manufactures or sells them. So you'll either need to get them custom made, or make them from "bits" like others have done (eg: gas cylinder brackets etc).

I ended up getting mine from Orion Optics in the UK but it wasn't a cheap, timely or a pleasant experience in the end.

[ving]

andrews com should sell rings for the 12"... try them first.

[iceman]

I don't think they do.. but i'd be very happy to be proven wrong.