Detection spells

Detection spells give the subject a new sense (beyond the normal five) or improve a sense the subject already has, for as long as they are sustained. Detection spells may be cast upon yourself or on another subject within touch range. The standard range of the sense a Detection spell grants is the spell’s Force x caster’s Magic in meters as a radius from the target of the spell. Extended-range detection spells have a Force x Magic x 10 meter range. The more net hits you get when casting the spell, the more detailed information you receive.
Using the extra or enhanced sense may require the subject to Observe in Detail as a Simple Action. Detection spells are either directional (like normal sight), area effect (work in all directions at once, like hearing), or psychic (providing some other special sense such as telepathy or precognition).
The sense is either active, requiring special efforts or actions to use, or passive, meaning it enhances the abilities of those affected without them having to take separate actions.
Active: Active detection spells involve an Opposed Test between the caster’s Spellcasting + Magic [Force] and either Willpower + Logic (+ Counterspelling if available) [Mental] for living things with auras, (Force x 2) for magical objects, or the object resistance for mundane objects (p. 295). Counterspelling may be used to defend against active detection spells, even if the target is ununaware of them being cast (for example, if they walk within range of an active Detect Enemies spell).
When a spell affects multiple targets, either because it has an area effect or because it is sustained and may be encountered by multiple people, you should only make a single Spellcasting Test. Every potential target then makes an individual Spell Resistance Test and compares their result to yours. New targets may be detected as they enter the range of the spell, and they must make a Spell Resistance Test against your original Spellcasting Test.
Passive: A passive sense is simply “on” and feeds sensory input to the subject’s brain like other senses—no interpretation necessary. While the spell is sustained, Perception Tests using this sense have a limit equal to the net successes from casting of the spell instead of the subject’s Mental limit. Counterspelling cannot be used to defend against a passive sense, but once an opposing spellcaster realizes there is an active sustained spell, she can try dispelling it (see Dispelling, p. 295).
Glitches: A glitch on a Detection Spellcasting Test may result in false or misleading information. Likewise, a critical glitch may inflict extra Drain (e.g., +2 Drain Value), translate any Drain damage suffered into Physical Damage, temporarily strip the subject of a sense, or inexplicably apply the intended sense to others (particularly opponents) in range—hopefully they’ll remember to thank you for your help in spotting you and your team.