look up at (someone or something)
To turn one's gaze or attention upward toward someone or something. Thomas, please look up at the board and answer the question! My dog looked up at me with her sweet, baleful eyes.
look up at someone or something
to raise one's gaze to someone or something. Would you please look up at me while I am talking to you? I hate to be ignored. Look up at the top of that building.