6 inch dobs.

[doug mc]

There seem to be two choices, Skywatcher and GSO. I am thinking of picking one up and making a new base from much lighter plywood. I have yet to see the GSO in any used classifieds. The GSO has a crayford style focusor, the Skywatcher has the agricultural rack and pinion. Would like to here from someone with experience with the GSO model regarding optical quality. It's a rare scope. The point i make about their focusors is because i use a binoviewer and the Skywatcher unit i think would struggle with one. I could replace it if you think the Skywatcher is a better performer. Thanks.
Have bought a new dob. No need to answer this one.

[doug mc]

Looks like i was right about the GSO 6 inch dobs being rare. No one has an opinion.

[doug mc]

Just bought a Saxon dob All's well.

[iborg]

Hi



I hope you enjoy! I think you have nice dark skies at Mt Tamborine


Philip

[Saturnine]

I have a Saxon 6" f8 dob that is quite a capable scope with a very good mirror,(same as a Skywatcher !) and am very happy with it . managed to take some reasonable planetary images with it last year.
The altitude bearing system and the focuser are the biggest drawbacks but with some tinkering they can be made to work better.
Have not looked through a GSO 6" f8 newt/ dob, so cannot comment about comparisons

[doug mc]

I did the usual dismantle of the focusor, clean out the glue grease and set the compression clamp with spacers. Remove the primary mirror cell and reset the rubber mirror clips so as to allow the mirror some slight movement. To stop the focusor tube from intercepting the light path i had to move the mirror forward 13mm by installing longer collimating bolts and springs. I have a lazy susan bearing coming, so work on the dob base will be ongoing. Having worked in engineering, tinkering is fun for me. First impression on the star test shows a little over correction but this is usual i hear for these scopes. With the moon low in the sky last night and seeing being far from good, craterlets in Plato were just starting to flicker into view. Going to have to machine a low profile adaptor for the focusor to allow binoviewer to reach focus with my 2x OCS. I have a Siebert 1.25x OCA which can reach focus using the standard 1.25 inch eyepiece holder that came with the scope. Both of these bino setups will work without the focusor tube interrupting the incoming light path. Some fun to be had.

[doug mc]

Ok, tonight was a little steadier, after doing the above i found that the star test looked better. Almost identical extra focal patterns now. My ronchi tester revealed straight lines either side of focus. Although the seeing was still far from perfect craterlets in Plato were obvious. Split beta Musca just fine and Alpha Scorpio showed its companion. This one is a keeper.

[N1]

The secret weapon of these 6-inchers is their focal ratio. An f/8 Newtonian is hard to get nowadays except as a 6" dob, yet can provide excellent high power and very clean low power views. I use a 6" SW dob occasionally, and it does not disappoint. Not surprised you split Antares with yours. Well done on securing one :thumbsup: