Benefit

As long as you have an air spell of 3rd level or higher available to cast, you can spend an immediate action to alter slightly the course of an arrow, crossbow bolt, spear, or other ranged weapon already in flight. You can't change the weapon's target, but you can apply a +2 bonus or -2 penalty on its attack roll. You and the target can be no farther apart than 10 feet per level of the highest-level air spell you have available, since the guidance occurs at the end of the weapon's flight. This feat works only on thrown or projectile weapons; it can't affect spells, powers, energy attacks, or the like. As a secondary benefit, you gain a +1 competence bonus to your caster level when casting air spells.