Tachyon scanner is a tech achievement in Master of Orion.
Tachyon Scanners detect the disturbances in the gravitic characteristics of normal space caused by the passage of ships travelling through hyperspace. These scanners have a base detection range of 4 parsecs. The differences in detection range caused by ship size still apply. Tachyon Scanners installed in Star Bases decrease attackers missile evasion by 40\%.