Is there any way to make an illusion of a wall look like a wall to an astrally perceiving eye? Physical illusions work fine against cameras, cyber-eyes etc., but if an astrally projecting character was flying down a hallway and turned a corner, is there at least a way that would require a perception or assensing check to notice that one of the walls was in fact a concealled hallway or door?

Can illusions be made permanent?

Thanks.

With a sweep of his...

Hat

A sustaining focus can maintain the illusion but a simple perception test on the astral will show the wall to be a spell.

I'm not positive, but I think Extended Masking can make it harder to correctly assense a sustained spell.

You can make illusions (or any spell) permanent with the quickening metamagic, but it costs karma.