I don't know if wiki is too technical. I like the level. There is a point where you just have to assume a certain level of background. The sun quote sounded just about right. It could be footnoted to explain what spectral lines are and how the wave lengths are dependent on the element being `burned' and emitting that particular wave length. And how that's the way we figure out what a star is made out of, what state its in and so forth. Or a link to basic astronomy entry that explains these details.
Since I am mostly self-taught in math and physical science I need a very particular level, above the pop level, but below the serious technical level or journal article level. It is very tricky to get this right. It depends on the specific topic whether I can understand it or not.
Examples. Scientific American is about the level that I think should be considered `popular'. Scince is more what I would be comfortable in. Nature is better, but if its on physics and math, then it's probably out of my range.
CG