From what I have read about building a solar filter for Newtonian scopes it is better to build an off axis filter that is smaller than than the actual opening - I just wanted to know how well yours works went built to the full 10" as I plan to build one.
I too wondered whether to do off-axis or full aperture, and heard conflicting reports. Someone very knowledgeable on CN suggested to me that when the seeing is good, you want as much aperture as you can get, so you should go full aperture.
It would be interesting, if you have some film left over, to make another mask with an offset 3" apeture and test them side by side to get a real answer. Hint, hint.
My film was 30x30cm, and my tube is almost exactly that.
