[mic_m (Michael)]

Originally Posted by JethroB76

Other than having a 'computer object locator' already fitted, what makes you say the Orions are really any better quality-wise out of the box?

Oh boy, with a question like this how much trouble can I get myself into and how fast? First off I should note that the COL is not really a factor for me; I would still want one of these without the COL; rather, it is the overall quality that this scope offers over others in the same budget scope category which makes it a winner for me.

I really don’t want to turn this thread into too much of a GSO vs Synta type thing (I kind of already made up my mind on what scope I want from what is available and this thread is more about understanding the Orion a bit better), but I will make and briefly expand on one basic overarching point in relation to your question.

My basic issue with the GSO dobs in terms of their quality is the degree of modifications that are needed to make a NEW scope work effectively. However, I will note that most issues with GSO dobs have a fix and once they are dealt with the GSO scopes would likely work just as well as the Orions. Though what we are talking about here is out of box quality, for which I believe the Orion is in front in many respects.

Problems with the GSO dobs out of the box include weak primary and secondary mirror support springs which make achieving and maintaining collimation very difficult (I learnt this through my own experience, especially in terms of the secondary spring but many others have reported this too). No such problems are reported with the Orions they have good primary and secondary springs form the factory as do other Syntas.

The GSO primary cell is not as good as the Synta primary cell. This is because the GSO collimation and locking screws are placed too far apart for the locking screws to be effective and using the locking screws may in fact damage the cell. To fix this (get the locking screws to work) one would have to drill new holes for them in the primary mirrir cell next to the collimation screws – no thanks! I would rather buy as scope that has them in the correct place to begin with like the Orion.

GSO secondary mirrors are often astigmatic due to the mirror housing design; this is not an issue with the Synta dobs that have their secondary mirrors attached directly to the secondary support and not contained within a housing as the GSO scopes do.

GSO secondary adjustment screws have pointed ends which dig into and damage the soft metal on the back of the secondary holder making collimation touchy. From my understanding Synta dobs secondary screws have flat backs that do not cause this problem and it is therefore ok to adjust the secondary mirror right out of the box without replacing the screws first.

Like secondary astigmatism, primary astigmatism has been a big issue in the GSO dobs. Primary astigmatism is usually due to the mirror being clamped into its cell too tightly. While this is declining in GSO scopes and it is generally an easy fix, it is virtually unheard of with Orion and other Synta scopes.

The bases of Synta dobs; the XX12 and SW Flextube both have supports perpendicular to the sides of the base; this stiffens the base structure reducing short term flexture and long term wear and tear. In contrast no GSO made dobs (neither the Lightbridge, the solid tube GSO nor the new 16” GSO) have support fins like the Syntas on the sided of their base and because of this, base flexture in GSO dobs has been reported as a problem encountered right out of the box, this is not the case with the Synta made dobs.

One of my major issues with all budget truss dobs (other than the Orion) is the “truss” (in some cases strut structure) itself. The 6 pole design of the LB makes a shroud hard to attach, but I prefer the LB design to that of the 16 inch GSO and the SW Flextube. The three struts on the 16 inch GSO and the Flextube look so fragile, but it’s worse than fragility; it is near imposable to attach an effective shroud without it sagging into the light path or missing the edges, the flextube is the worst in this respect due to its raised poles. While the LB is ahead of the others the Orion is ahead of the LB in my opinion. Its trusses are built like a tank with 8 poles and a shroud that is easy to attach and is kept well away form the light path, unlike the other scopes mentioned.

Also there have been numerous reports of GSO tubes rusting, though this may have been before the new ASDX models that came out last year; nevertheless, I have never seen any reports of Synta scopes rusting which gives me more confidence the finish of Synta scopes. In fact I recall a review in AS&T last year comparing the finish on the reviewed Synta scope as being close that of a vehicle.

Finally, on the very rare occasion there are instances of GSO secondary mirror astigmatism due to the mirror itself; there have been even rarer, isolated instances where some have replaced their defective GSO secondary mirrors with nother GSO secondary and got another defective mirror. While this is certainley not a big issue in the sea of GSO dobs out there it has made me more cautious about the scope out of the box; perhaps this is just a non-rational over reaction to what is just a minor issue.

As stated above it is important to note that all of these issues have fixes, and some may indeed enjoy spending time and money doing this. However, one should be aware that fixing some of the preceding issues would void the scopes warranty; think about it; the warranty would be voided for trying to fix something that should already be working – the irony! I have read about some people making an awful mess of their scope trying to modify it because it was not working – you really have to know what you are doing. This just scars me right away form new GSO dobs. I might consider a well modified GSO if an opportunity presented itself.

I would also like to note here that I have looked through several GSO dobs at my club that performed excellently, but they all needed substantial modifications to get to that stage. I am just not the kind of person who enjoys fixing issues that I believe should have been taken care of at the factory, especially when they are so numerous and when some can be quite challenging. So my preference for an Orion dobs is due to its seemingly better quality straight out of the box.

I have listed some references that back up my comments - there are better ones but this is all I have time to find right now:

Checking the Optics of Your GSO Dob:
- Primary and secondary astigmatism, general observation of the compromises that GSO dobs can come with.
Link

Guan Sheng 12" Dob:
- A weak secondary spring, weak primary springs, sharp secondary screws, sideboard flexture
Link

Astro-Tech 16” Dob:
- Collimation knobs in the incorrect place, weak springs, sharp secondary screws, sideboard / base flexture,
Link

Go to dobsonain kits and read: a word about collimation:
- Correct primary screw placement, primary cell damage
Link

Got my LB 10 - collimation ?- eyeball vs sitetub
- Secondary astigmatism
Link

Dob repaint and My 10" GS Dob REBORN! - Cutting and powder Coating
-GSO dob rust
Link and;
Link