Starlight

Exploration Stage: Historical Museum
From: Ursula Hartley
Description: I think something is glowing, or rather flashing, in that miscellaneous pile of exhibits. Maybe that glowing object is creating a time anomaly. Can you help me find it?
Completed: This is a starlit, astronomer's map! It was sealed with chains, but you broke the seal. I can see Clarissa Stokes's library bookplate. How in the world did this map end up in her library?