When Harry received that cryptic note, I thought "watcher of stars" meant the centaur. Now that you propose this hypothesis, I'm inclined to thinking that "tear apart the very stars in heaven" means Harry will defeat Quirrell in such a way that Quirrell will survive, but will never be able to cast that wonderful stargazing spell again. Harry likes that spell more than I think is normal, but removing it sounds like a particularly cruel punishment for an astronomy fan.
New chapter!
This is a new thread to discuss Eliezer Yudkowsky’s Harry Potter and the Methods of Rationality and anything related to it. This thread is intended for discussing chapter 104.
There is a site dedicated to the story at hpmor.com, which is now the place to go to find the authors notes and all sorts of other goodies. AdeleneDawner has kept an archive of Author’s Notes. (This goes up to the notes for chapter 76, and is now not updating. The authors notes from chapter 77 onwards are on hpmor.com.)
Spoiler Warning: this thread is full of spoilers. With few exceptions, spoilers for MOR and canon are fair game to post, without warning or rot13. More specifically: