Another diagonal focus issue

[xa-coupe]

I have a diagonal from my telescope (all sizes 1.25) that I want to use on my finder scope so I don't have to contort into uncomfortable positions whilst aligning. Works fine in my refractor (90x900) but no focus at all on either of my guiding / finder scopes. (ZWO 30F4 and a 50x190 f3.8 SVBony ). I've used a couple of different eye pieces but no change. Those eye pieces work just fine in an inline arrangement.



I'm sure there's something silly I am missing.

[bojan]

There is considerable light path through diagonal.. you have to shorten the tube to compensate for this.