Wo gt81 focussing

[goldblade1983]

Hello

Recently bought a 80mm William optics gt 81.

Having difficulties focussing as follows:

1. Eyepieces that I have are 1.25. I can only focus my 40mm eyepiece and only at max length focus on scope plus diagonal plus pulling out eyepiece slightly. Not possible with 21mm or smaller. Is that normal? Do other more expensive eyepieces have shorter focus distance requirements?

2. Next plugged in dslr with wo field flattener. Again can only focus at around max focus distance on scope and by not fully inserting the field flattener into scope.

Scope looks great when focused but worried about this not pushing in fully will just end up with flex. Am thinking I will need a spacer but the retailer had suggested I wouldn't require one?

Can anyone help? Wondering if having to go to max focus is normal and curiously what equipment you would use at shorter distances. My dslr is a Sony a300 which uses minolta a mount

[ronin]

Little surprised that the eyepiece has to be at the end of travel.

Not too surprised about the flattener and camera. I suspect that the flattener is extending the focal length, so an extension could be required for that. The GTF is the same lens but the "focal length" is longer owing to the built in flattener.

I cannot recall reading anyone else having a problem with eyepieces, but that could just be I didn't register it.

[Sp@ce_d]

Hi

I got my GT81 this week.

I don't know about eye pieces I've not tried any. This is purely for imaging for me.

So far clouds are not playing ball but I'm surprised how far out the drawtube is to reach focus as my ZS71 focuses at half that & was wondering the same thing re. flex.

I've been trying to get a decent V curve in FocusMax tonight but so far every attempt hasn't completed because of clouds.

It does seem the focus point is out around 3 inches. Thats with an older GT81 flattener only, SX FW & OAG, Atik 314L+ hanging off the end. I'm still waiting for the dedicated GT81 reducer to arrive. Is that the one you have? There's 3 different versions depending on model. I have one for the ZS71 but its too long according to this..

http://www.firstlightoptics.com/reducersflatteners/william-optics-reducer-flattener-6.html

[Ibbo!]

I think it is like most WO and designed so binoviewers can be used.

My 132 has to have 4" of adapter stuck out of the drawtube 

[goldblade1983]

http://stargazerslounge.com/topic/209056-wo-gt81-ff-dslr-tube-extender-needed/ this person had same problem

[goldblade1983]

Yes I have flattener for gt81

[ronin]

That seems odd for what is basically a visual scope, still the world is odd.

There is no chance that a WO diagonal is "longer" and so the idea is to use one of their diagonals ?

That is about the only reason I can think of and that seems a little strange for WO.

See you have just "flipped" over to 51 posts, welcome to the classifieds and so the potential of spending more money. :grin: