QUOTE
Astral Signatures (SR4a p192)
Magical skills and abilities produce an astral signature on anything affected
by them, which is detectable using assensing. An astral signature
is the magical “fingerprint” of the Awakened creature who created it. A
signature lasts for a number of hours equal to a magical effect’s Force
after the effect ends. Foci and other magical items (like magical lodges)
always contain the astral signature of their owner (or owners).
A character can attempt to read an astral signature with an
Assensing Test. Three or more hits are required to detect the signature.
Once seen, a signature can be recognized if the character sees it
again (perhaps requiring a memory test, as noted on p. 139). With
five or more hits, she also gets an impression of what magical effect
created the signature (the magical skill used and the general class of
spell or spirit).
Magical skills and abilities produce an astral signature on anything affected
by them, which is detectable using assensing. An astral signature
is the magical “fingerprint” of the Awakened creature who created it. A
signature lasts for a number of hours equal to a magical effect’s Force
after the effect ends. Foci and other magical items (like magical lodges)
always contain the astral signature of their owner (or owners).
A character can attempt to read an astral signature with an
Assensing Test. Three or more hits are required to detect the signature.
Once seen, a signature can be recognized if the character sees it
again (perhaps requiring a memory test, as noted on p. 139). With
five or more hits, she also gets an impression of what magical effect
created the signature (the magical skill used and the general class of
spell or spirit).
QUOTE
Astral Tracking (SR4a p193)
Nearly all magical things (spirits, spells, foci, and magical lodges) have
an astral link to something. Active spells are linked to their casters,
spirits are linked to their masters, astrally projecting magicians are
linked to their physical bodies, and foci and magical lodges are linked
to the magicians who activated them. Awakened entities who are aware
of these links can follow them and track them through the astral plane
back to their sources.
Following an astral link requires an Assensing + Intuition (5,
1 hour) Extended Test, modified as noted on the Astral Tracking
Modifiers table (p. 192).
Nearly all magical things (spirits, spells, foci, and magical lodges) have
an astral link to something. Active spells are linked to their casters,
spirits are linked to their masters, astrally projecting magicians are
linked to their physical bodies, and foci and magical lodges are linked
to the magicians who activated them. Awakened entities who are aware
of these links can follow them and track them through the astral plane
back to their sources.
Following an astral link requires an Assensing + Intuition (5,
1 hour) Extended Test, modified as noted on the Astral Tracking
Modifiers table (p. 192).
QUOTE
From the astral tracking modifiers table (SR4a p192)
condition : Each hour passed since astral link was active
threshold modifier : +1
condition : Each hour passed since astral link was active
threshold modifier : +1
Apologies for the wall of text, but I want to check to see if I am interpreting this correctly - magical activities will leave a signature on whatever it is used on and said signature can then be tracked (if it is noticed in the first place) at increasing threshold until it finally disappears. Which leaves magicians who do not clean up after themselves magically vulnerable for quite a few hours after using their mojo?
I can see the worse case scenario already: Mr Bad-ass Wage Mage (with a brace of bound, high level spirits) is called in to investigate the site of a break in on Corp X's property. The magically active intruder happened to leave a signature behind which he is able to assense.
Calling in his posse of spirits, he then gives them the following orders: follow the astral link of this signature to its source, then manifest and teach an object leason to the shadowrunning scum about why they should not mess with corp X. The posse of spirits should not take more than a couple of hours (using teamwork) to follow the link.....and half a dozen or so spirits manifesting unexpectedly on top of any PC mage should cause a world of hurt.
Have I missed something or should magicians be real careful about what traces they leave behind? (especially the ever popular overcast stun spells ... thats a long time for the signature to disappear)