Long range sensors

The long range sensors are sensors situated in Atlantis, which can detect things with a small portion of the Pegasus galaxy, including ships moving in hyperspace. The exact range the sensors cover is unknown, but the area it covers can give Atlantis up to three weeks advanced warning of the approach of Wraith hive ships. Other space faring races, such the Asurans, can give up to a day's warning. Rodney McKay was able to modify the sensors to locate the subspace frequency used by Wraith trackers.