A "Star Tracker" is a device used in astronomy and space exploration to accurately determine the position of stars in the sky. It helps spacecraft and telescopes align themselves by referencing the positions of celestial bodies. This technology is crucial for navigation and observation, ensuring that instruments can focus on specific stars or other astronomical objects. Star Trackers typically use cameras and sensors to capture images of stars, which are then compared to a database of known star positions. This allows for precise calculations of orientation in space. They are commonly used in satellites, space probes, and by organizations like NASA and ESA.