A Blacksun Filter is an advanced optical filtering suite employed by Tau military units that comprises of several unique sensors and lenses, similar in function to the Photo Visor of the Imperium. A Blacksun Filter boosts ambient light and makes certain frequencies of light visible to the wearer, magnifying a warrior’s low-light vision. The filter is also designed to temporary block out extremely bright lights that could otherwise blind the user in battle. This is especially useful for Fire Warriors to avoid being blinded by their own Photon Grenades. With Blacksun Filters, target calibration systems sensors can also lock onto enemies with full efficiency and range even during night-fighting operations. This has proved to be a major advantage for Tau forces in many campaigns, where surprise night attacks can be conducted with full efficiency upon unsuspecting enemy forces.
All Tau Battlesuit primary sensor clusters are fitted with Blacksun Filters as standard, and infantry helmets can also mount Blacksun Filters as part of their optical systems. Some Tau Pathfinders have also been known to wear the filters independently, often taking the form of a set of elaborate goggles or visors. Tau skimmers and aircraft can also be upgraded with Blacksun Filter systems as necessary to meet the particular tactical demands of their intended mission.
- Codex: Tau (3rd Edition), pp. 18, 20
- Codex: Tau Empire (4th Edition), pp. 26, 28, 30
- Codex: Tau Empire (6th Edition), pp. 68, 70, 72
- Imperial Armour: Aeronautica, pp. 58-64
- Rogue Trader: Tau Character Guide (RPG), pp. 26, 31