Opinions needed on Collimation!!

Ok, let’s open Pandora’s box on collimation one more time. I’ve currently disassembled my Orion XT 8 to flock the tube. I finally received my Techtron collimation tools and a book on the fine art of collimating a Newtonian. In the book “New Perspectives on Newtonian Collimation Principles and Procedures” the author stated that one should square the focuser to the tube, however gave very little information on how to achieve a “square” focuser.

First question, how do you square the focuser? Keep in mind that this is a Vixen focuser and it doesn’t have collimation screws like the JMI version.

Second question, is squaring the focuser necessary? I read from this site: http://w1.411.telia.com/~u41105032/myths/myths.htm that squaring the focuser is a myth. I understand that you want your light cone to be perpendicular to the eyepiece but isn’t this achieved with the adjustment of the secondary?

Clear Skies,
David Pope

True, there are some primary cell location and secondary holder configurations that would be OK with a skewed focuser, but usually we want the Newt components orthogonal with the focuser as reference datum and the primary aligned with the tube axis.

To square the focuser, just measure the tube's circumference and use a sight tube or laser to see a mark or hole on the opposite side with equal semi-circle lengths. Don't use wobbly 1.25" adapters. Adjust or shim the focuser as necessary.