Peripheral Mage Sight is the passive perception of the Supernal in the Fallen World
Peripheral Mage Sight is always active. The mage sees — rather, perceives — magical occurrences through the lens of her Path and Nimbus. Many mages experience the Periphery through senses other than sight. A sensual Mastigos might feel brushing, light touches on his skin, while an Acanthus might hear mercurial laughter. Many Moros sense the supernatural through their sense of smell, tasting decay and chemicals on the air. Deeper levels of Mage Sight rely on knowledge of the Arcana, but the Periphery responds to all supernatural events.
Note, however, that Peripheral Mage Sight notices only active supernatural effects. Any supernatural attempt at concealment hides the effect from the mage, without a Clash of Wills or any other mechanical effect. Peripheral Mage Sight, for instance, doesn’t detect a ghost lurking quietly in Twilight. If the ghost spends Essence, activates a Numen, or Manifests, however, this attracts the mage’s attention.
Nor does Peripheral Mage Sight give any clues as to what just happened — only that magic is afoot. If the mage doesn’t have the Death Arcanum to use Active Mage Sight with, the ghost will remain a nagging sensation of something out of place at the edge of the mage’s perceptions.