This section on sensors applies only to long range sensors - those used to scan other star systems, and it does not apply to combat situations where sensors are always on and used.
All long-range sensors in Battlestar Galactica are FTL sensors, but they cannot be used while the ship is actually in hyperspeed. This is because the sensors have a time lag of a couple of microns per centar of sensor range.
This is the main limiting factor for hyperspeed travel. A ship can only travel as far as it can see, and if its constantly attempting to outrace its sensors, then this poses a problem. As such, a ship can only travel as far as its initial sensor sweep before entering hyperseed, which is where the sensor range comes in.
Sensors and communications work normally within a star system.
A ships sensor range is measured in centars. This centar range is the same as that found on the astronavigation maps. This range is always as x1 multiplier. A ships sensor range is equal to the Active Sensor and Comm range (page 45) x 0.75 centars (round down, minimum 6 centars). Thus a TL 10 Viper with a level 7 enhanced tactical array has a range of 7 centars.
These sensors only allow voice and data communications over FTL distances, but no visual. They can allow a ship to navigate over FTL distances, but do not allow detailed astronavigation details of another star system save for basic planetary bodies. Ships of any type cannot be detected in other star systems.
These allow for much greater detail than basic sensors and also allow for visual communications over FTL distances.
Enhanced sensors give more detailed information about planetary systems, such as planets and moons, and large ships can be detected as well - ships with a SM +14 or larger.
Science sensors give greater detailed about planetary systems - such as atmospheres of major planets, gas clouds, radiation reading etc, but less detail about ships. Ships larger than SM +15 can be detected.
Tactical sensors give greater detail about spaceships within a system, but less detail about the contects of the system. Only basic planetary details are available - amount of planets - but the sensors will detect all ships of SM +12 or larger.
FTL sensors can only be used in an active way - passive FTL scans do not exist, and in addition the sensors are not on all the time, they must be used as a scan.
Note that sensors work in a line-of-sight way and are blocked by planetary bodies. Most sensors will be able to determine moons and planets through gravity and orbits, but it does allow enemy ships to hide behind planets and thus be invisible to scanning ships.
FTL communication between ships or planets has a range equalling the sensor range of the ship. Communications can be broad (sent to anyone within range) or narrow (sent to a single specified target which must be located first).
FTL communications has a time lag of 1 micron per centar range.
FTL communications, like sensors, do not function in hyperspeed.