Tal Celes was a Bajoran Starfleet crewman who served aboard the Ursula, an CR90 Corvette, which became stranded in the Delta Quadrant. Celes was a grade three sensor analyst assigned to Alliance's astrometrics department under Seven of Nine, the department's head. Celes especially had difficulty with sensor data analysis. As a sensor analyst, her work had to be constantly double-checked much to Seven of Nine's immense irritation. Often, Celes had to call upon her closest friend on Voyager, crewman William "Billy" Telfer, to help her with the analyses.