Celestron 8x50 finder problem

I need a really smart guy for this one, I came into owning a Celestron 8x50 finderscope that I think has been modified with a mirror diag. and a 20mm eyepiece. It's got a focus ring on it too (helical?) Trouble is that when it's dialed/focused all the way "in" (overall shortest length) it'll almost focus on celestial objects but not quite. Is there a different eyepiece I can put in it that would be in the range of focus? Something like a 15mm or a 25mm? Not sure which way to go. I'm assuming this would act like a small refractor which I know nothing about.

Thanks

I'll post a pic if anyone thinks it might help.

Jeff

I have several of those type finders. If it has .96" eyepieces then it is original and not converted. Yes my friends, they used to actually put real focusers on finders. This finder should have come with a .96" reticle eyepiece. Not sure if 20mm is the right size. How close are the objects you are trying to focus? Have you tried it on stars? I've attached an image of a similar Meade 8X50 with helical focuser.

Don W

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