Hearing that the Eclipse Cannon did more damage than the nuclear bombs does not make Shadow feel any less weird about this conversation. It's a fact he could have figured out for himself if only he'd thought about it for a moment, but hearing it said outright is different.

He's only too comfortable to accept the change of subject, even if he's not entirely sure he wants to actually help Waver. He hasn't had a problem working with the various children and other animals he's encountered thus far, but Waver is neither. And while Waver hasn't introduced himself yet, his observations make Shadow think he must be some sort of scholar—perhaps even a doctor of some sort, with all the baggage that comes with.

But it seems like he's at least trying to get them out of this mess, so Shadow decides to not rebuff him outright.

"What does a star chart look like?"

Shadow's been stargazing, but he's never seen an actual astronomical or astrological chart before.