Detect Scrying

Level: Arcane 4; Components: V, S, M; Casting Time: Attack action; Range: 120 ft.; Area: 120-ft.-radius emanation centered on you; Duration: 24 hours; Saving Throw: None; Spell Resistance: No
You immediately become aware of any attempt to observe you by means of scrying (including the scrying spell). The spell's effect radiates from you moves as you move. The spell also reveals the use of crystal balls or other magic scrying devices. You know the location of every magical sensor within the spell's area.
If the scrying attempt originates within the area, you also know its location. If the attempt originates outside this range, you and the scrier immediately make opposed caster level checks. If you match or beat the scrier's result, you get a visual image of the scrier and a sense of the scrier's direction and distance from you (accurate to within one-tenth the distance).
Material Components: A small shard of mirror and a miniature trumpet.