ZWO Finder Scope Focusing issues

[bomberbaz]

Hi all and for those who know me, ltns.

Ok and to the point, I bought one of these http://www.365astronomy.com/ZWO-60mm-Finder-and-Guide-Scope-with-Non-Rotating-Helical-Focuser.htmlas a finder scope that will also take a webcam for assisting with my Video Astronomy.

The issue is it simply does not focus with any of my eyepiece as there is not enough travel, I would say it is around 25mm short. I have tried taking out the 40mm spacer and inserting a 45mm extension tube but cant get it to focus still. I discovered that by leaving 10mm of the ext tube hanging out and the same with the eyepiece I xcan just achieve focus but thats not ideal.

Just wondered then if anyone else has come accross this issue with this scope and how they solved it.

Also if anyone else has ideas that would be great.

Steve

[Cornelius Varley]

Without a diagonal or an extension tube of sufficient length most refractors will fail to reach focus.

[bomberbaz]

I have got round it Peter. I have ordered from 365 the rotating focuser that gives an additional 19mm of focus travel. (Actually he gave me one for free did Zoltan, good men)

Then Orion do a 1.25 - extension tube of 50mm. I believe focus wont be an issue with these modifications, cheers.

Steve

[ngwillym]

I found that a 'spare' Barlow with lens removed solved my similar problem on a Celestron 70 Travelscope.

[bomberbaz]

I dont have a cheapo spare barlow otherwise that could have been an option, good idea though. However the ext tube i ordered has a very long tube insert which would allow to not fully insert if there is still a small shartage in travel. I think looking at the dimensions there is a chance it could still need a few millimetres but i will know once the parts arrive. Good job i love mechano.