The Prism Cannon is a massive two-stage laser weapon and the primary armament on the Eldar Fire Prism grav-tank. A mid-strength laser is aimed at a large, artificially-grown psychocrystal prism. This prism causes a significant amplification of the destructive power the initial laser possesses, emitting the energy either in a single blast of power or as an unfocused beam to provide a weaker shot with a larger blast radius at the touch of a rune. Most unusual of all, a, sophisticated tracking arrays allow this technological wonder to narrow its field into a thin lance of light; forming an all-powerful laser beam that can fell even a Necron Monolith with a single shot.
Prism Cannon beams can be combined by firing one into the crystal of another. This allows the final Prism Cannon in the sequence to fire a beam with a proportionally increased power output compared to a beam fired by a single Prism Cannon. Another area where the Prism Cannon excels is its range, as it possesses twice the reach of a Scatter Laser or Pulse Laser and can strike targets that are just visible on the horizon. This makes the Prism Cannon equally dangerous as an anti-aircraft weapon, and allows Eldar assaults to open up with a punishing Prism Cannon barrage before the enemy is even aware of the arrival of Eldar armour units on the field.
While efforts by the Imperium to capture and study working examples of the Prism Cannon have been mostly unsuccessful, a basic understanding of its inner workings has been achieved by the Adeptus Mechanicus. A two-stage firing process sees a medium-magnitude laser from the primary charge chamber fed through an acceleration chamber into a massive psychocrystal prism, which traps and intensifies the shot within a fraction of a second. This energy is then focused through a secondary prismatic lens, which can be adjusted by miniature motors to produce a highly-focused energy beam capable of blasting through the thickest of armour or a dispersed beam for slaying entire squads of enemy infantry. Thanks to sophisticated targeting arrays within the Fire Prism grav-tank itself, this weapon can also channel its energy through the mechanisms of second Prism Cannon as described above, producing an energy blast powerful enough to obliterate even the toughest targets.
- Codex: Eldar (3rd Edition), pg. 15
- Codex: Eldar (4th Edition), pg. 43
- Codex: Eldar (6th Edition), pp. 44, 63
- Epic Swordwind, pg. 22
- Imperial Armour Volume Eleven - The Doom of Mymeara, pg. 175