Mirror quality question, GSO/skywatcher

[Grahame (Grahame)]

Hi All,

I'm looking at getting larger size dob for visual and planetary occasionally prob a 12" in size. My question is what is the difference between the gso and skywatcher mirrors?

There is quite a large difference in prices between both of them but does this translate into quality of the mirrors?
I'm not worried about the focuser or tube specs as these can be replaced and or modified easily enough.

Thanks,
Grahame.

[Merlin66 (Ken)]

Get someone with a Ronchi grating to take an image of the optics...this will quickly show if they are good or not.

[Grahame (Grahame)]

Unfortunately I do not know anyone with these scopes and was hoping to hear from people's experances with them. I have heard stories of some bad (meaning a torchlight behind them shows unevan coatings) mirror coatings here and there for example.

[AG Hybrid (Adrian)]

Both my scopes are skywatcher newts. Nothing negative to report about them. They put up great views. Coatings are fine.

[peter_4059 (Peter)]

I've been happy with my GSO - haven't held a flashlight behind it yet though!

[Grahame (Grahame)]

Cool Peter, give it a shot and see
I am an Ex-owner of several GSO scopes now and each one was of very high quality but as i suspect there might be the odd one that slips though its QA net...

After giving it some more thought - I could get the cheaper 12" GSO dob and have the mirror re-coated (possibly re-figured also?) and still come under the skywatcher price

decisions, decisions.

[Waxing_Gibbous (Peter)]

I've had both and never had a problem with either.
GSO has a rep. for tighter QA but ...who knows?

You could always just buy the tube and add a Zambutto /Pegasus /OOUK mirror.
But then you might want to change the cell. Maybe the spyder also. And that dob base is a little 70s - how about an Al or CF custom jobbie....
Never stops with Newts!

[Grahame (Grahame)]

Hi Peter,

you must have been down this road before!

[skies2clear]

Haven't looked through a 12" of either but I have a 10" Saxon which I believe is same as Skywatcher which has a very good mirror. Seeing permitting, I can routinely use a 5mm eyepiece on planets with it, and when it's really good, a 4mm as well. A friend has a Bintel 10", same as GSO and that works very well too.

My Saxon has a pyrex mirror, but not sure if Skywatchers use pyrex anymore? GSO is BK7 I think.

[Shiraz (Ray)]

Hi Grahame. If any help, I have a 12inch GSO Dob - comparing with images in Suiter's book, it is corrected to about 1/7 on the wavefront, has minor TDE and minor surface roughness. It is very good to use, allowing about 500x in good seeing and snapping into focus. Some scattering from the TDE and roughness can be seen on very bright stars if you look for it, but that is not a major issue and it really does perform very well overall. BK7 mirror, but that is not a practical issue. Regards Ray

[AG Hybrid (Adrian)]

Originally Posted by Grahame

After giving it some more thought - I could get the cheaper 12" GSO dob and have the mirror re-coated (possibly re-figured also?) and still come under the skywatcher price

decisions, decisions.

Which Skywatcher are you looking at? My 12 inch cost me about $1000 brand new?