I have one of the Lunt-branded APM 152mm ED APO refractors that came to me second hand. It's a really nice scope for the money, IMO, but I've got a frustrating problem: the focuser seems to be angled slightly with respect to the light path. With my Howie Glatter (RIP, good brother!) laser collimator in the focuser, I can't get the spot on the objective to be in the same position when I rotate the focuser (in the different rotational positions, it ends up describing about a 10mm circle--that just seems like way too much). Rotation of the focuser and German equatorials kind of go together, so I don't want to give up on the rotation option.
It really seems like somewhere in its shipping, that the focuser got whacked and it or the backplate is now effectively bent just a bit. It's also possible that the focuser just isn't up to maintaining alignment when rotated regardless of whether it sufferred a whack or not.
So, I'm looking at a new Moonlight focuser (with their cool bearing-cam adjustment for centering the focuser tube to the light path). I suppose I could try to find out if APM could supply a new backplate (which seems the most likely culprit) and perhaps a new focuser (I haven't investigated what they might be able to do yet--or even tried to detach the focuser from the backplate).
If anyone has any DIY suggestions, I'd be grateful to hear them. Also, if someone has experience with the focusers on these babies, perhaps you'd know if it's worth fussing with or if replacing it is likely the way to go.
I can supply photos of the thing if that'll help with the suggestions.
Thanks for looking!
Edited by AlphaGJohn, 18 January 2020 - 06:55 PM.