4" APO or 5" Achro???Posted By Domenic Quadrini |
If your 12.5" Dob has a 2.5" diagonal or less, why not use a 5" off-axis mask? You'll get 5" apo-like views for the cost of a piece of cardboard and a can of flat black spray paint. I do this with a C-14. Works great once the tube currents have settled down. Dom Q.