FAB Sensor, p.195 Hard Targets
FAB SENSOR This sensor function can be added to any sensor package. This sensor can only determine the presence or absence of active mana sources in the immediate area, not the exact source or strength. Background count temporarily reduces the effective Rating by an equivalent amount. The bacteria sealed within the sensor require special sterile feedstock to maintain at a cost of 50 nuyen per month.
The spell in question is manascape, p.20 Shadow Spells
MANASCAPE Type: M Range: LOS(A) Duration: S Drain: F – 2
This spell is designed to pass illusions to the target’s magical senses. While it cannot create auras of astral images where none are present, it can change their appearance to anyone using Assensing, Psychometry, Sensing, or the Astral Window spell. False Impression only affects the image of a single spell or astral form, while Manascape changes the appearance of an area.
I hope that clears that part up
