A GSO 8x50 finderscope, I'm guessing? Is it properly seated in its holder? The rubber O-ring is properly located? The spring-loaded stud properly located in the groove in the finderscope body? Is the problem that you cannot get the object that you have centred in your eyepiece, in the centre of the crosshairs when you adjust the screws on the finderscope? That is the screws hit one end ot other of their travel and you are still not centred? Check that the bolts holding the finderscope mount to the scope body aren't loose and the mount is moving. (The bolts are countersunk philips head screws into the mount with nuts and washers inside the scope tube - you need to remove the finderscope and its dovetail bracket to see them.) I discovered that if you loosen those off (CAREFUL - if you decide to undo them all the way, don't drop a nut on your primary mirror - eeeeek!) then you can adjust that mount to a different position and retighten - maybe the mount has moved. Perhaps the mount needs a little adjustment to align it properly to the scope body and bring the object back into the range of adjustment of the thumbscrew. This is probably only an issue if it is the horizontal adjustment screw that is not reaching the right position at either end, but perhaps also the vertical, but I cannot imaging it unless there is some swarf or shim tilting the mount with respect to the tube.
And, as recommended, this is a job for daylight - looking at a very distant earth-bound object - a TV antenna is great. Just be careful not to point the scope (or finderscope, especially if you take it off) at the Sun.
Let us know how you go? Take a few photos and post them if you still have a problem - maybe we can spot a problem.
Do you know anyone else with the same finderscope? Try theirs on your scope and vice versa?
Eric
