Glueing the primary in its cell

I used silicon to hold the mirror in the cell. I used three "dots", and placed the mirror on three sets of pennies (5 each I believe) to hold the mirror off the cell until it dried. After collimation, I'm getting a slight double vision. When I focus on Mars, I see a faint second and sometimes thidd Mars. The faint "reflections" come closer in line with the real Mars but not completely. Is this a collimation problem or have I used to much silicon? Maybe I should have made the silicon dots smaller. After the mirror (13.1 inch) pressed them down at bit, they are about a quarter ($0.25) in size, maybe just a hair larger, and about 3 or 4 mm tall. Maybe just a dab will do you using silicon. Anyone had similar experience?

Dave:

This would probably be more appropriate in the reflectors or telescope making forums.

Anyway, a 13.1 inch mirror probably will require more than 3 dots of silicone for proper support, especially if it is a thin mirror like many of the old Coulters. I believe they were 1 inch thick...

Jon