I was recently given an ETX125 "Premier" Edition with dead mount. This is the one with NGC 7000 printed backwards on the tube graphic. I de-forked the scope and want to use it on a GEM I have on-hand. First I want to look at it with the Ronchi. I've searched but can't find any quick ways of getting the mirror spacing correct for infinity focus. If someone knows about where the focal plane should be with the spacing correct, please tell me! Or perhaps there's a certain eyepiece with the field stop at just the right place when the scope is focused at infinity?
I have the manual as .pdf files but have just barely begun to dive in.
Any tips are appreciated.