Any prime focus issues with the William Optics GTF81 ?

[choochoo_baloo]

The GTF 81 I ordered is arriving Monday. I phoned a telescope supplier to check that a certain 2" T adapter would be compatible with this 'scope, for attaching my Canon DSLR to it, and he warned me that the c. 80mm WO refractors have a reputation for prime focus issues in the past. He wan't sure about this newer model though.

Obviously at worst, I would just need an extension tube if the focal plane of the 'scope is beyond full travel of the focuser. Obviously this can be checked once the 'scope arrives, but I just wanted to check in advance, if other users have reached focus without any extension tubes then there's nothing to worry about. Just impatient!

Thank you.

[wuthton]

I'd be prepared for needing to extend, I've always needed one for prime focus on all the scopes/cameras I've owned.

The focus travel is designed for a diagonal and eyepieces as it is easier to extend a camera than withdraw an eyepiece inside the scope.

[Astrosurf]

I have a WO Megrez 72mm and use a field flattener which allows focus and connects directly to my Canon. Do you have one?

Alexxx

[groberts]

You may be interested in my recent post, I got there but is was difficult. In the end my understanding is now that without a field flattener you will certainly need an extension tube (FLO do three for the WO GT81) and maybe even some spacers. With the field flattener it's just very, very fine to focus - within a fraction of a millimeter is what I am finding but excellent when you get there. Good luck.

 http://stargazerslounge.com/topic/221636-wo-gt81-imgaging-help-needed/