I would suggest you try the easy way: Adjust the optical axis to your focuser instead! http://www.skyandtelescope.com/howto/diy/3306876.html Nils Olof -------- I'm having some problems with off axis aberrations in my f/4.77 Dob. Would someone please help me a link or a procedure how to properly align the focuser to the optical axis of a Newtonian.