Star maps, also called star charts or star-charts, depicted the locations of stars within the galaxy using cartography. These maps were crucial for astrogation.
The Jedi Order possessed numerous star-charts that indicated the positions of mythical Force vergences; however, by the time of the Galactic Empire, a large number of the known vergence star-charts were actually elaborate forgeries. Genuine star-charts discovered during this period were often millennia in age, making their interpretation extremely difficult.
During the Galactic Civil War, the Empire engineered Bledsoe's disease to induce a "window-effect" (mimicking stars in the eyes) as a symptom, coupled with an ocular scan to extract the associated star charts. The intention was to provide a discreet method for disseminating intelligence about Rebel bases to Imperial forces, enabling their location and subsequent destruction.
Hugo Bartyn successfully removed the coordinates for the Lamaro system from the majority of existing star-charts.