In reading the Shadowrun core rulebook, I ran across something that sorta confused me and I am wondering if someone can give me an assist. According to page 183, a magician can erase an astral signature. However, I am a little bit unsure of what that exactly means.

My interpretation is this. If Tom the mage murdered a gang banger with a mana bolt, he can erase the astral signature to eradicate evidence of him being there by taking one Complex Action per Force of the signature. Tom, however, cannot go to his magical lodge, which serves as a astral barrier, and erase the astral signature there because it is an active magical effect unlike the astral signature of the mana bolt, which is more or less residue from a spell effect.

Basically, my question is can astral signatures from active magical effects such as astral barriers, quickened spells, anchored spells, sustained spells, etc. be erased or must the magician wait until the effect is no longer active and then erase the astral signature to get rid of evidence that said effect ever existed. Any help would be appreciated.

Logically, you can erase the sig of an active magical form (sustained spell, etc), but so long as it is active it simply creates a new sig as it interacts with the surrounding ambient mana. So you could erase it, would doing so would be pointless (like erasing the foot prints of an elephant on an open dusty plain)

I think you want the rules for Extended Masking in Street Magic pages 60-61. Be advised that you can't Mask everything though.

Thanks, just wanted to make sure.