Astronomy is more than just observing; it's making sense of those observations. A good theorist needs a good imagination... and no fear of being wrong. Aryabaha in ancient India and Ptolemy in ancient Rome, the medieval bishops Oresme and Cusa, the 19th century astronomers Schiaparelli and Pickering, all rose to the challenge; and they were all almost correct. Which is to say, they were wrong... sometimes hilariously, sometimes heartbreakingly so. What lessons can 21st century astronomers take from these discarded images?