[fauxpas (Tony)]

Knocking up a home made solar filter and someone said regardless of the aperture of the scope, you only need 3"... Is that true? If so should the hole be offset like I see on a lot of scope end caps?

Secondly, if I want to view the entire sun in the eyepiece and I have a 4" Dob at 640mm focal length, what eyepiece would I need? I'm imagining 30mm or more...

Thanks...