William Optics ZS66SD Focuser - Adjustment Help or Possible Upgrade Options?

[AdeKing]

I have a WO ZS66SD which I use as my travel scope as I can get a WL solar, terrestrial and astro setup into its tiny briefcase with a second bag for a relatively compact Manfrotto 055B tripod for support.

However, whilst I absolutely love this little blue OTA, I have a real problem with the focuser which I cannot seem to get right.

When you turn the fine focus it works for about 5mm of travel and then stops moving the draw tube, you then need to tweak the focus with the coarse focus slightly and the fine focus works ok for about another 5mm then you need to repeat the above ad infinitum.

Searching Google seems to suggest that this is a problem with the tension thumb screw under the focuser, but I have tightened this as much as I dare and the problem is still there.

I have tried and tried to adjust the focuser following instructions in the WO micro focuser upgrade instructions (courtesy of the Wayback Machine) and a thread on CN, but I can't seem to get it right.

As its driving me to the point of distraction I'm thinking about just upgrading the focuser, as its a decent enough scope for me to consider a nice focuser, but I'm not sure what my upgrade options are and Google doesn't yield much in the way of results.

Firstly, does anyone have any suggestions for adjusting the stock focuser, has anyone else had the same issues? If so, how did you fix them?

Has anyone upgraded the focuser on one of these small WO OTAs?

In order to think about an upgrade, what measurements to I need to take?

Many thanks for any suggestions you might have, either way.

Regards,

Ade

[Knighty2112]

I get the same thing on my Opticstar AR90S. The fine adjustment won’t work very well with certain EP’s in the scope, and past certain altitudes when viewing. I then normally have to use the course adjustment to wind the focuser back in again. I tried smoothing off the drawtube to give it a flatter surface to see itf that cured it, and messing around with various thin tabs inside the focuser to bring it tighter onto the draw tube. Never worked well, so now just live with it. 

Edited April 4, 2018 by Knighty2112

[Star Struck]

Hi Ade, I had the same thing with an Equinox focuser. In the end I gave up and bought a Moonlte.

 

Tony

[AdeKing]

Thanks @Knighty2112 and @Star Struck, not sounding good so far.

Sounds like it might be a case of more money or just living with it.

[Stargazer McCabe]

@AdeKing I wouldn’t give up just yet...

When I purchased a previously owned ED120 I had problems with the focuser that initially led me to the frustration and ‘upgrade’ considerations you are reaching. But I managed to resolve my issues through finding the link below.

Now, our scopes are very different. But I just wonder whether there is an adjustment screw that could help you  ?

My problem was that with a 2 inch diagonal and a 2 inch 100* eyepiece the draw-tube couldn’t be ‘racked back in’ and, indeed, kept slipping out gradually. Initially I tried to resolve the issue by using the focus lock knob, but after a quick tweak to to the tension adjustment screw all was well again...

https://teleskop-austria.at/information/pdf/SWD200goto_Skywatcher_Crayfor-Auszug_justieren.pdf

Edited April 4, 2018 by Stargazer McCabe

[AdeKing]

@Stargazer McCabethanks for the link, it was my first point of reference.  I have also had these problems with and ED80 focuser that I upgraded my ST102 with as the stock R&P focuser was absolutely rubbish.

The link that you provided proved successful with that focuser after much gentle tweaking, and is now works a treat.

Sadly, none of the adjusters on the WO focuser bear much of a resemblance to the ED80 focuser, the only one that is similar is the focuser tension adjuster, which I've reached the end of my tether with, as I just cannot get it adjusted correctly.

I think that I might go right back to basics, remove the microfocus assembly and start totally from scratch following the WO instructions below.

I don't really want to spend any more money so I'll persevere for a while at least.

WO 10_1 Microfocuser Retrofit Instructions.pdf

[newbie alert]

Hi Ade, I know what you mean about it driving you nuts..i have a zs80d  and the focuser drives me mad..i contacted W/ O as it's a old scope and they wanted me to send the focuser back to them..not wishing to be without the scope for a while I've found this old thread on cloudy nights..not sure if it's relevant to yours..

https://www.cloudynights.com/topic/570335-upgrading-the-focuser-in-wo-zs80-10th-anniversary-scope/

[Stargazer McCabe]

 @AdeKing Understand. It was worth highlighting incase you hadn’t seen it and the adjustment screws were similar...

But given they aren’t and you had I guess I didn’t help much at all ?? 

Good luck finding a solution ??

[AdeKing]

11 hours ago, newbie alert said:

https://www.cloudynights.com/topic/570335-upgrading-the-focuser-in-wo-zs80-10th-anniversary-scope/

@newbie alertThanks for this link, I hadn't seen this one and it looks like a useful resource.  I've bookmarked it and will try to dismantle the focuser and re-adjust again tonight.

Ade

[JonathanLangton]

Hi,

I have just purchased a second hand WO 80 ED II which suffers from a similar problem in the fine tuning knob. It is actually so loose that, although it spins when moving the regular knobs, it does not grab at all the focuser, it spins freely without any friction.

I'm trying to find out if it is possible to dismantle the fine knob to tighten it up but I am not able to open the yahoo group described in the Cloudy Nights topic, where Timm Bottoni described this process.

Is it available in some other place? 

Does anyone know if the group does still exist?

Thanks for your help!!

Jonathan

[simrisks]

Did anybody fix this issue having same.joys with the ZS66 at moment, had perfect working. With DSLR but installing a mono and filter wheel has meant I cannot get it working despite micro tension adjustments.  Looking at totally new focuser and potentially a whole new scope. Which is a big shame, as I do love this little gem

[AdeKing]

1 hour ago, simrisks said:

Did anybody fix this issue having same.joys with the ZS66 at moment, had perfect working. With DSLR but installing a mono and filter wheel has meant I cannot get it working despite micro tension adjustments.  Looking at totally new focuser and potentially a whole new scope. Which is a big shame, as I do love this little gem

I upgraded my ZS66 with a Moonlite as I couldn't initially get on with the stock focuser and got a lot of movement of the FOV when racking in and out.

However, I later dismantled the focuser, cleaned it and carefully reassembled it and through careful tweaking managed to get it working nicely before I sold it on with the stock focuser.

Moonlite do, or did offer a specific ZS66 flange not sure if it's still the case with their recent announcement and changes, but you could put out a wanted Ad for a Moonlite dual speed focuser.

If you decide to go that route then PM me as I may be able to help you with the ZS66 flange.

Ade