Astronomers in Mesopotamia used a group of stars, called ziqpu, in order to indicate and measure time at night. How exactly this was accomplished is unknown. Were they directly observed in the night sky as part of this time-telling practice, or did they belong to some kind of theoretical scheme that allowed astronomers to describe time? The talk will explore the evidence for both these possibilities. It will be presented at the 64th Rencontre Assyriologique Internationale (RAI) annual meeting in Innsbruck, Austria as part of the Stars and Constellations in Babylonian Astronomy workshop.