GSO 10" dob vs Skywatcher

[rob.scott]

Newbie - contemplating GSO dobsonian 10 or 12"
- good first scope choice?
- pitfalls of this ?
- advice?

Thanks

[nsavage]

I can't compare the brands but I can say that I went with a SkyWatcher 8 inch Dob for my first scope a few months ago and am so far extremely happy with it. I did add the Lacerta 10:1 focuser upgrade however which is very nice. Quality wise I was very happy. So much so that I have another 8 inch F/5 on the way for Astrophotography.

I can't compare size against the 10" or 12" either but I will say that the 8" is surprisingly bigger than I expected and whilst it is easy enough to move around I feel that the 10" would be too cumbersome for me to take out of the home regularly.

[Startrek]

I just sold my first scope 2 weeks ago which was a 10” Bintel GSO solid tube dob manually operated. A great scope to start off with, had it 2 years and enjoyed nudging around the night sky. It was stored in my garage and pulled out on a flat bed trolley to my obs location 6 metres away. I wouldn’t consider a 10” if your observing at a remote location,it’s a big scope ( but a lot of people do ) An 8” would much easier to handle if it’s being transported away from home.
I now have a Skywatcher 12” GoTo Dob , still stored in the garage and I use a parcel trolley to pull it out and set up.
Both GSO and Sky-Watcher are manufactured in Taiwan / China with a reasonable level of quality and finish.As far as optics go I’d say the Sky-Watcher is a little better than the GSO but the difference is marginal dependant on your eye pieces. I thought my GSO dual focuser was much smoother and a better feel than the Sky-Watcher dual focuser.Skywatcher have recdeveloped, expanded and pushed their products world wide for the past 5 or 6 years especially in the US.They have a great product range across the board now
If your intending to use your first scope at home and away I would recommend either the 8” GSO solid tube or the Skywatcher 8” solid tube dob and if the budget can stretch a bit maybe the 8” Sky-Watcher collapsible GoTo Dob
If your just going to use the scope permanently at home go for the 10” GSO solid tube dob or 10” Skywatcher solid tube dob
My 2 cents worth .......

[N1]

Having owned the 6" version of the Skywatcher, and the 8" and the 10" GSOs, my impression is that the SW is of slightly better quality overall than the GSO dobs (optically the 6" was outstanding, not least because of its relaxed f ratio of 8, and a great scope for the planets), but the GSO certainly aren't junk either and I actually prefer their focuser over the SW unit. My copy of the Skywatcher dob did not have a proper 2" interface, but some odd, threaded thing that was supposed to make attaching a camera easier but needed an adaptor for 2" eyepieces. My RC astrograph (a GSO) has proper 2" fittings so the SW solution seems unnecessary. My ultimate pick of the 3 was the 8" GSO, giving the best package of aperture, cost, portability and serviceability (mirror comes out for a wash every so often) and has been a great workhorse ever since I got it 3 years ago. The MDF mount is starting to show some wear but the OTA is still in great shape, despite countless trips in the back seat of my car. I sold my 10" GSO dob when moving to NZ permanently - a great scope, but a bit too great to fit on the plane with me, unlike the 8". One thing I noticed about the 10" is that the tube seems unnecessarily large at nearly 12" external diameter, leaving a big gap of unused space around the mirror. The 8" is more efficient in that respect and its tube much smaller than the 2" difference suggests.

Re 10" vs. 12" - I had the same question before buying the 10", and some of that decision making process happened here. (http://www.iceinspace.com.au/forum/showthread.php?t=117819)

Edit: duplicate post deleted

[doppler]

I have a 10" skywatcher dob and the tube has a much smaller diameter than the GSO. I have GSO tube rings on it and had to pad them out (about 30mm less diameter than GSO) My 10" fits on the back seat of a lancer with the dob base, so go the aperture, 15kgs is not a big weight.

[N1]

That would settle it for me

[AndrewF]

I've had a skywatcher 12" and currently have a GSO 12". I can't see any difference as far as the optics are concerned.

The GSO version has a lot of nifty features that make it nicer to use like a right angle finder, tension knobs, micro-adjust focuser, single 1.25/2" adaptor, quicker to collimate etc.

HOWEVER, it also feels like it might fall to pieces in a few years time. The Skywatcher was a lot more solid even if it didn't have the above features.

I'd just go for whichever one you can find the cheapest.

[Merlin66]

Robert,
Based on thirty years experience with many Dobbies and other reflectors I would say a 10” aperture represents a sweet spot, much more light grasp than a 8” and certainly not as large and heavy as a 12”.
You are more likely to get out and use the 10” and the views it will give give you may even exceed your expectations.......
Highly recommended.

[glend]

Andrews is running their 10% off sale on both the Skywatcher and GSO dobs for the rest of this week. A good time to buy. I have had 10", 12", and 16" GSO dobs and they are good quality scopes, and the Alt bearing brakes are first class. Having looked through many dobs over the years I still believe the GSO mirrors are higher quality than the Skywatcher ones. However, GSO do not make Goto versions of their dobs, and I don't understand why. Given the 10% off sale I would be buying the Skywatcher 10" goto dob, it is heavier than the push to version but it is easier to use and you don't need to worry about setting circles and other things, like Nexus wifi and encoders added to the GSO to see where the scope is pointed.

[raymo]

You do have to take care that if you buy a GSO dob that it has sufficient back focus to allow the use of a DSLR; many of their past models didn't
[unless advertised as an astrograph.] I don't know if it has changed with their latest models. SW models always have, and still do, as far as I know.
raymo

[astro744]

I bought a used SW 10" f4.7 for the kids and whilst it is a nice 'scope to use it does have one annoying feature in the focuser. I cannot fully insert my 2" Astrosystems laser collimator as there is a stop inside the draw tube of the focuser making it difficult to see the return beam from inside the tube.

[raymo]

There must be something wrong Astro, the 2" adaptor that fits onto the focuser so that you can use 2" eyepieces is about 56mm deep[from memory].
How far in does your laser collimator have to go? My laser collimator slides in
fully, which is about 25MM. I don't have the scope any more, so I can't compare anything, but I don't remember any stop in the draw tube. Are you using the adaptor when collimating? The stop is not something to do with using 1.25" eyepieces is it?
raymo

[astro744]

My SW focuser is the black body type. The focuser body height is 60mm. A 12mm collar with a male thread and single locking screw screws directly into the draw tube which is part of the focuser body. It is this collar that has the internal stop preventing any 2" accessory from protruding further into the draw tube. A 45mm 2" eyepiece adaptor (labelled as such) with a tapered base connects to the 12mm collar and is held in place via the single screw. The entire adaptor can be rotated by loosening the single screw. I believe this is where one would replace the 2" adaptor and add a shorter T-Ring if wanting to attach a camera thereby gaining 45mm less the thickness of the T-Ring.

Im not sure of the purpose of stop inside the collar but it prevents any 2" accessory being lowered further into the draw tube. My Astrosystems laser is 2" diameter and just over 100mm long (4"). The approx 5mm Barlow attachment clips onto the end of the collimator. To see the return beam whether with Barlow attachment or not I need the end of the collimator visible from inside the OTA but because it is unable to travel that last 60mm it means it cannot be seen at all making collimation impossible with this particular collimator. (It woks very well on my other custom 10" with GSO focuser).

In fact even a Paracorr cannot be fully inserted, something which for f4.7 could be more used than not. The Paracorr 2" part is 60mm long and sticks out 15mm because of the collar meaning I cannot reach focus with it in place.

As I said I bought this for the kids and they will be using without a Paracorr and so far it has provided some very pleasing views and I am happy with it as it is relatively light and small for a 10" telescope.

If I had access to a lathe (and knew how to use one) I would bore out the stop and problem solved, (or I'll just get some 1.25" collimation accessories).

[Allan_L]

This is true.
My Paracorr did not fully go into the focus tube either. (SW 10" DOB).
I read somewhere about a hack, to file around the tube enough to allow the Paracorr to fully insert.
This I did and now all seems well.
But I too am wondering why it was there in the first place.

[doug mc]

Having used both brands over the years, i found the GSO mount to be MUCH smoother to operate at higher powers.

[raymo]

O.K Allan and Astro, I've been thinking back and having reread your posts
I sort of think I know what is going on.
Mounting a DSLR is simplicity itself. The tube that an 1.25" eyepiece
slides into is mounted on a flat plate that has a bevel on the side opposite to the eyepiece tube so it can be secured into the collar by the retaining screws on the outside of the collar. The eyepiece tube unscrews from the plate, exposing a male thread on the plate which screws directly into the T-ring on the DSLR. This provides about 12mm of back focus. Just remove the flat plate from the focuser ; with the tube removed just screw the flat plate into the camera's T-ring. Put the camera in place on the focuser, rotate the camera to a convenient position and nip up the securing screws on the outside of the focuser collar.
2" eyepieces or other 2"accessories are not meant to enter the draw tube at all. The aforementioned flat plate that has the tube for 1.25" eyepieces on it is removed from the collar, and the 2" eyepiece adaptor is inserted into the collar, and the securing screws on the outside of the collar nipped up. A 2" eyepiece, or any other 2" accessory can slide in to the full depth of the 2" adaptor. SW have never explained this in their manuals; many people have been confused.
raymo

[Allan_L]

yep. I have often told people of the method to attach DSLR to the 1.25 plate, and done it myself.
But this does not have anything to do with the problem of attaching a Paracorr to the 2" focus tube, as far as I can see?
From memory, the part that had to be filed off was on the actual draw tube itself. (But, Its been a while since I did it).

But cheers, good talk to you again. Actually I am pretty sure I originally learnt about the T Ring attachment method from one of your earlier posts. :thumbsup: :thanx:

[raymo]

Why would a Paracorr have to be inserted more than the 50mm or so that the eyepiece adaptor allows. My 2" collimator and my 2" barlow worked fine, what is different about a Paracorr? I've never owned one.
raymo

[astro744]

Thanks raymo but I too concur with Allan_L. The issue with the stop inside the 12mm collar preventing 2" accessories from being fully inserted is puzzling since removing this stop would have no impact on the use of the focuser both visially or photographically.

I have no desire to photograph with this telescope and am aware of the pros and cons of various focusers out there and that some are better designed to equip a camera than others. In fact the best photo-visual focuser that I have ever used and still have is the Tectron Telescopes focuser made by the same company that used to make quality collimation tools (Sarasota, Florida). I only replaced it on my 6" f5.5 because I not longer do photography and this focuser also has no compression clamps although I will replace brass screws with nylon one day.

This focuser had a separate base plate to which you either insert the visual body or photo body and they were designed such that the photo body could be made parfocal with the visual body to suit any eyepiece/SLR combination. It worked very well for me at the time.

Back to the SW stop issue, I too will file it out as it is really a non-essential item. No other focuser that I have come across prevents accessories from being inserted inside the draw tube.

As to the original post I have not used a GSO scope so cannot compare but the 10" SW does the kids nicely and is not too heavy and has plenty of aperture in a compact size. I would recommend looking in a store at both before you buy and judge for yourself.

[raymo]

I can't fathom out for the life of me why any 2" accessory needs to enter the draw tube at all, the focal point is well outside the draw tube; certainly eyepieces, barlows and collimators don't.
The 2" adaptor allows accessories to slide in about 50mm, how much more do you need?
raymo

[astro744]

Reason 1:
I cannot see the return beam spot on the end of the laser collimator because it sits 60mm up into the draw tube as viewed from inside the OTA. If I were able to insert the focuser further into the draw tube as I can do on my GSO focuser I could easily see the spot. Yes there are other collimators available but so are there other focusers.

Reason 2:
The Paracorr type 1 has a 60mm nosepiece. I can only insert 45mm and as a result cannot achieve focus. Again I have no problem with the GSO focuser.

I cannot fathom why a focuser design would provide a stop to prevent accessories being fully inserted other than to prevent items slipping in and hitting the mirror. I cannot think of a single accessory that is 2" diameter along its entire body and if there is one out there it would not be common enough to require this annoying safety feature.

Both of the reasons I mentioned are common applications that other focuser manufacturers have accommodated.

[raymo]

Fair enough; I did ask what was different about a Paracorr, and now I know.
cheers raymo

[astro744]

No worries, raymo. I just had a closer look at the collar that screws into the draw tube and I now know why the stop is there. It isn't because a stop was needed or intended as a safety feature but because extra thickness was needed to accommodate the male thread that goes into the draw tube. If it were possible to leave at 2" I.D. I'm sure it would have been done. My electronic vernier battery is flat so I couldn't measure how close to 2" it is but it does only need a minimal turn down on a lathe.

Anyway, I have digressed here although it is still relevant to comparing GSO with SW. There are many other factors to consider and the focuser is just one of them.

To the OP; whatever you choose, enjoy!

[Allan_L]

I am no techno expert Raymo, but from what I can tell, the whole point of the Paracorr is to get the eyepiece at a particular position hence the micro adjusting height (turntable) to use for different eyepieces. I would think that it needs to be fully seated to achieve this.

http://www.televue.com/pdf/literature/Pacacorr%20Type-2%20Instructions.pdf