I want to know the answer to the following question:
What was Challis looking for when he saw Neptune the first two times?
All the background I'm provided with is that "Heinrich d'Arrest, a student at the observatory, suggested to Galle that they could compare a recently drawn chart of the sky in the region of Le Verrier's predicted location with the current sky to seek the displacement characteristic of a planet, as opposed to a fixed star.". Is that enough to answer the question?
Answer: no