In this scene (Act II.ii), Romeo is hiding in the Capulet's orchard the morning after the party, and happens to see Juliet framed by the window. Romeo is speaking in metaphor in these lines, comparing the window to the East, and Juliet to the sun (after all the run rises in the East). He is breathless with her beauty, and struck anew by his love for her. And while he is talking to himself, he continues the conversation, basically asking the universe to move her into a better view. Essentially, this entire scene is about Romeo mooning over Juliet in infatuation, but those first few lines are metaphorical, comparing Juliet to the radiance of the sun.