Rich, Coulter scopes work very well as manufactured, but, that said, upgrades make certain tasks easier. It would help to know what the owner's primary concerns are, concerning the functionality of the scope. Imagery can only be affected to a very minor amount, assuming the mirror coatings are still in decent shape and it's collimated.
From my expereince, the mount itself would be the fist thing addressed. I'd replace the cheap molded plastic furniture bearings with real Teflon, then my second upgrade would be a decent focuser. Third would be a real secondary spider. Depending on the vintage, a primary cell upgrade would be last.
What finder is your neighbor using? That is a concern, as well. On Mon, Feb 27, 2012 at 4:30 PM, Richard Tenney <retenney@yahoo.com> wrote:
My neighbor is trying to refurbish a 13" Coulter Dob, and is asking me for advice, hence me turning to the group here. Have any of you had experience upgrading this scope, e.g., secondary, mirror cell, focuser? Any input is welcome...