At Chapter 13 in Harry Potter and the Goblet of Fire, Lavender Brown squeals excitedly:
'Oh, Professor, look! I think I've got an unaspected planet! Oooh, which one's that, Professor?'
Professor Trelawney peers down at her chart and says:
'It is Uranus, my dear.'
Unable to resist the opportunity, Ron pipes up:
'Can I have a look at Uranus, too, Lavender?'
Professor Trelawney is less than amused at Ron's little comment, and it is this, perhaps, what makes her give them a large amount of homework at the end of class.