Oh, cool it, you two. Here's Dovina doing all sentence fragments (and getting called on it):
http://www.poemranker.com/poem-details.jsp?id=113457
So clearly she doesn't think it's such a violation. For my bit, I think you'd do good without "that" but with "the" before "horizon's". Dropping articles always looks like bad fortune-cookie writing to me. I've long ago stopped caring about fragments, unless they're your whole poem.