Long-range sensors are starship arrays designed to detect ships, stars and phenomena at distances measured in light-years, using subspace to see faster than light.
Because light itself is too slow for interstellar scanning, long-range sensors rely on subspace signals to gather information on objects far beyond visual range. They give a ship advance warning of approaching vessels and allow crews to chart nearby systems before arrival.
The arrays sacrifice detail for distance. Long-range readings are often vague until a ship closes in, and they can be spoofed or blocked by interference and cloaks. Science and tactical officers rely on them when scanning far ahead of a ship's course.