newbieMaria

Hate to say it but it will have got a bump or knock and so moved. Indoors = warm, outdoors = cold and bits move. Like just about anything they need a check and reset at intervals. People do not go bumping mirrors or diagonals but they still have to check and reset collimation. Finders are more likely to getting in contact with things then a secondary, spider or main mirror, they stick out.

I agree, just a gentle touch can be enough to knock them off slightly.

I usually re-align them on the moon (if its up) or on a streetlight / TV aerial - thats usually enough to get the finder close enough.

I pretty much accidentally knock mine every session.