HK,
I don't know if this is the kind of thing you are looking for, but we have enjoyed "Turn Left at Orion" by Guy Consolmagno--the nice thing about this book is that the stars, etc., one is meant to find are all viewable with small telescopes or binoculars--some other books assume the availability of much more high-end equipment. Gary Seronik's binocular astronomy book is good, too.
This may not be sophisticated enough for her, but do you know Richard Moeschl's "Exploring the Sky"? It's one of the Chicago Review Press books for gifted middle-school science--we have enjoyed that one here, but my laddies are younger than your daughter--might be worth taking a peek at a library copy.
Do you ever cruise the Well-Trained Mind message boards? There are several astronomy buffs there (I'm thinking of Jean in Wisconsin, particularly) who might have some really good ideas for you.
Would she be interested in building her own telescope? There are lots of websites with instructions for making your own Dobsonian scope, for instance--might lead into some interesting stuff about optics and so on....
It sounds like fun!
mm
ETA: I haven't seen these (though I've used some of their other curriculum) but TOPS science has some books they developed in concert with NASA; their books are cheap and quite nicely designed, with lots of experiments--worth a look?
Last edited by minniemarx; 02/15/11 08:47 PM.