Since Astral Perception is a "Psychic sense" (SR4A, p. 191) that does not use any of our regular sensory organs, it seems to me it should be in all directions at once. Thoughts?

If this is so, then sneaking up behind an astrally perceiving being should be more difficult than on one perceiving on the physical plane. Comments?

Yes, sort of. This makes AP even better on the physical plane.

Infiltration, however, is abstract, and doesn't technically rely on the target looking away. Feel free to play with the DP mods on SR4A p136 (e.g., Perceiver Distracted) as appropriate, regardless of 360 sense. After all, they already apply to hearing, smell, radar (sometimes, sense/sensor rules can be wonky), etc.

Makes sense.

remember we, people, are use to focusing htough. you might sense all aronud you but your attnetion would focus so the projection would' turn that way. I think of it as you have a really good sense of your environment. you 'hear' and 'feel' someone moving behind you even though you can't see them etc.

Right: use the appropriate Perception mods (+3 Actively Looking, -2 Distracted, etc.).

Eyeband cyberware (Augmentations, page 37) provides no bonus to detection wile providing a 360° vision either.

no bonus is still much better than cannot see, because it's behind you

That's not what he meant.


As for Astral Perception... I have always seen this as working "like" sight, and not in the way of a sense granted by a detection spell (like Detect Life).

Bye
Thanee

Remember that AP doesn't work through objects, of course. Cover still applies.