Illusions deceive perceptions on the physical plane, yes. But you can show me an example, in any edition, where they have fooled sense on the astral? Let us start with phantasm and trid phantasm. One is mana based, one is physical based, the only real difference in the spell is that one is not detected by cameras. In the astral, both auras look the same until assensed, they both show up as spell auras.

Then we have invisibility and improved invisibility. When sustained upon a person they make them undetectable to the metahuman eye (or cameras, ultrasound will still show them unless they have silence on them as well). One version actually wraps light around the target whilst the other simply fools the mind into not seeing the physical presence of that target. On the astral, you would again merely need to perceive to notice a spell aura on top of a metahuman aura unless they had been masked. Now, if you wanted to know that the aura was in fact an invisibility spell, then it's a simple matter of aura reading it. But if you see a door open and close, with nobody around, and you decide to astrally perceive and see an aura moving about... I'll give you 10:1 odds that it is a person with an invisibility spell on. Or if it shows as a spirit aura, someone being concealed.

Okay. If you cast a trid phantasm spell on the physical plane, an Astral only being would not be able to see the illusion because of the barrier between the planes. An astral spirit would or a projecting mage would look at a character with Improved Invisibility cast on him and see that character as plain as day.

Casting a mana illusion on the astral plane allows observers with no physical presence to see the illusion, although those with no astral presence cannot. While a magical aura would be noticeable, there would be no way to infer what exactly the magical aura is without assensing.

Jeez, I mean, the description of the Invisibility spell even states flat out that the subject's aura is still visible to astral perception. Are you going to tell me that's "Unique to invisibility because it's in the spell's description", Demerzel?

But you still assume that it carries an aura of "here there be a spell", when really the spell is not the item created, it is not localized at the object or any of the objecs. The fact that you give away for free that it is one of a limited list of objects including real but enspelled is misleading. The aura of the phantasm won't be localized on any object created by it, it is not cast on the illusory object it is cast on the area. You look at yonder phantasm and all you see is the phantasm. The aura, that's ill defined, and I don't see why so many people think that it somehow instantly invalidates the illusion, or even more simply calls attention to it.

Demerzel, according to the spell description the mana version of Invisiblity pulls the exact same Mind Rape that the other mana Illusion spells do, but yet we know that it is useless against Astral Sight because illusion spells can not affect Auras, including their own. The fact that a Mage has failed his 'save' against the mana version of Invisiblity has zero bearing on his Astral Sight despite having fallen victim to the spell's Mind Rape.

That is why so many people disagree with you and I dare-say that perhaps you should think about reconsidering your "misconception of Astral Space."

Because there is no reason for a cardboard box to have a bright, shiny aura about it... I'd say thats a pretty good reason.

<edited to include the above post>
Which is precisely what I said earlier and was consequently ignored. The only ability that can change an aura is the masking metamagic. There are no spells that can affect the aura of a spell or effect on the astral plane (short of say a healing spell on someone from near death, that would change their aura intrinsicly)

Sure they can. If you roll no successes on your assenssing test you've been fooled, there is no doubt about that. But you still know the location of said magical aura and the only way for it to be hidden is through masking.

What magical aura? Where is it? Around the box? Why is it around the box, cite your source.

edit: nm, misread.

That does not come close to implying that a nonexistant figment of your imagination carries the aura of the spell that created it.

No, that comes close to stating that spell have auras that are immediately obvious, both in presence and basic nature.

What is implied in the whole chapter is the fact that entity and Aura are linked and move inseparable.

That means that your illusion of a carbox may not leave the shadow of a real carbox, but will have the aura of a spell - which is obvious, no test needed.

The box doesn't exist. The spell exists, and the closest thing that says anything about where the aura of the spell is is this statement:

The question of where is the aura is a profound one. And it's not well specified. I feel a little trapped because you went from 60 m to 60cm, I'd be more inclined to say it's somewhere between that perhaps.

It is an AOE spell. The box is only part of the effect of the spell. You could have 100 boxes or a variety of things. The area of an AOE spell is base radius equal to force in meters, and can be expanded by witholding dice.

The spell itself is a sphere of (Force +/- modifiers)m in radius. Perhaps the aura is a sphere as well...

Actually, it would hide your aura if the box was large enough, since a character can't see through the illusion without resisting it. While the observer would know that the box is a phantasm illusion with enough assessing tests, the observer would not know what is in the box as it would remain fully opaque from the observer's perspective.

One could take advantage of this by creating multiple phantasmic astral boxes and hiding in one. However, it is important to note that this really only helps if you are projecting or if your perusers are always astrally active, because a phantasm spell cast on the astral plane will be invisible to a purely physical observer just as an illusion spell cast on the physical plane will not do anything to a purely astral observer.

Consider this scenario:

Bob the occult investigator is fleeing from Tom the combat mage. Bob switches into astral perception, making him dual natured, so his illusion spell also will affect both planes. Bob runs around a corner into an alleyway, and casts Phantasm; he creates an illusion of the far wall 2 feet closer than it really is, effectively narrowing the alley by two feet. The scene he creates also contains illusion of him running down the alley away from the combat mage. To complete the scene Bob makes a large fire elemental blocking the path.

His hope is that Tom the combat mage runs into the alley and sees a fire elemental standing there. If he’s astrally perceiving he can tell that there’s an illusion in effect and decides that perhaps the fire elemental is an illusion to stop him and looks past the elemental and sees his quarry fleeing down the alley around another corner, continues the pursuit.

Now the spell has an aura. Most importantly it is a single aura, so at best the aura encompasses the entire area of the spell. Tom would have to assense the wall to see that the shadow of the wall is not convincing enough to fool his assensing. Since it says that Illusions cannot fool assensing, however Tom needs a success on an Assensing Test to make that determination, and unfortunately the powers that be decided that the Combat Mage didn’t need assensing skill.

One thing to remember though is WHY a magician would use astral perception if he sees something that ”looks” obvious.

If there is an illusion of someone throwing himself into a cab and driving away (with the hunted target hiding somewhere) then the magician is the target of the spell as soon as he enters the spells area. If he believes the spell then he would indeed find a way to track his target.

If the magician is a subject of the spell he might just believe that the target got away. Lets then say that “someone” he hunted drops the spell as soon as the illusionary cab is gone then there isn’t anything obvious on the astral, unless the mage makes an assensing test.

On the other hand – if the mage is already looking at the astral the spell would be obvious and he would see a spell is active.

Sure, but the whole point of the thread was 'why you can't get around astral perception'.

I just noticed this thread and sat down and read the whole bloody 6 page mess. What immediately struck me is the irony in Demerzel's repeated declaration "That's your misinterpretation, not the rules," when clearly everyone else here including myself can see that it's Demerzel who is clinging to his own misinterpretation of the rules. No offense meant.

Just had to see what kept this topic going so long.

Ciao! =)

Yea, that's the way I'm looking at it now. It seems like a clever use of illusions should be capable of misleading even astral observers, and in potentially time sensitive cases could be very useful.

The blanket stement that illusions are inneffective vs. Astral Observers is what I'm questioning here. They appear rather to be differently effective.

There, now, isn't that all better? I think this calls for a song!

Song

I don't think that it has satisfied Rotbart van Dainig yet.

*Screams and shoots pbangarth until his clip runs dry*

Are you trying to Horror Mark the entire forum?

*Sits down and hums that soul sucking song over and over to himself*

You clicked the link? Don't you know links on DSF are like books in Call of Cthulu... Click at great peril to your sanity.

True, but forbidden knowledge is like a moth to a flame...

Or is forbidden knowledge like a flame to a moth?

Not if you strike and reverse it. You have to remember, I've just been exposed to mind numbing horrors from beyond the fringes of reality that man was never meant to know.

that last one is a good point, rotbart. one of the things sorcery cannot do is cross the planes. Even if the casting magician is dual natured (astrally perceiving) at the time of spellcasting, the spell can only affect one plane.

Also a good point is that the illusion of a fire elemental will either have the aura of a spell, or no aura of its own (depending on your interpretation of how the aura of area effect spells appear). Neither will the phantom mage running down the alley.

If the casting magician had called down a real fire elemental, hoping his pursuer would think it was an illusion, astral perception would immediately reveal that it had the aura of a spirit.

I'll try and be specific:
Nothing says an illusion spell cannot create something that looks at a casual glance like an aura. The fire elemental will look like a fire elemental should in astral space, as will the illusion of the guy running down the alleyway.

The only limit an Illusion has is that it cannot fool assensing with respect to an aura. You must succeed on an assensing test or you're fooled.

Yes, however Rotbart van Dainig and 2bit brought up some very damning counterpoints Demerzel.

For the sake of argument lets assume that an astral illusion can create what seems to be the astral form of a spirit and a man to someone who is merely using Astral Vision. (Granted the rules doesn't specify that the Spell can do that.)

However, even if you grant that it can create a psudo Aura, it also leaves its true Aura on everything that it touches which in the case of Bob's scene, stretches across the entire alley, including the Fire Spirit, Fake Bob, and the False Wall.

Also remember that at worse making an Assensing Test is a Complex Action, and can even be done while running, albeit at -2.

So assuming that the 'default' dicepool of 6 dice (Rating 3 in both Stat and Skill, although I'd imagine that in most cases Shadowrunners will tend to have a higher Dicepool to draw upon.) the odds of a pursuing Mage seeing through the illusion are as follows.

Stops and Assenses the Scene: 64.8834019204389%

Assenses the Scene while running: 40.7407407407407%

Assenses the Scene while running & distracted: 11.1111111111111

Now if we assume that he really wants to catch Bob and is willing to spend Edge for a dicepool of 9 dice the scene breaks down thus. (Note, I'm not sure if Scot Gray's Diceroller understands the concept of Exploding 6s, so that might change the odds quite a bit.)

Stops and Assenses the Scene: 85.6932378194381%

Assenses the Scene while running: 73.6625514403292%

Assenses the Scene while running & distracted: 53.9094650205761%

So even under the best of situations where the pursuing Mage is hurried and distracted provided that he still has some Edge left to spend (And lets face it, this is the type of situation where Edge is supposed to be spent so if he's got it then he'll spend it.) a merely average mage will still see right through Bob's Illusion better then half of the time. And even if he doesn't pierce the Illusion itself he'll know that sorcery of some sort is at work in that Alley, and it doesn't really take a Thaumatury Major to guess that more then likely the trickery is going to be some sort of illusion.

So I guess upon further reflection I'm back to the posistion that Illusion spells are really rather useless against Astral Vision, because even if you assume that they can create a psudo Aura (And if they can create a psudo Aura then why can't they disguise a real one to casual Astral Perception?), they will always declare that there is a working spell present and that by itself will oftentimes be enough to ruin the illusion's effectiveness.

However, I think a previous poster said it best, the trick is to create an illusion in such a manner that the pursuing Mage doesn't think to use Astral Vision on it in the first place. After all, how likely is a Mage to switch over to Astral Vision after seeing his prey jump into a taxi and speed off?

First off, the question of meaning, as in, the intention of the author, is best left to a mail to Rob.