[Black]

Can a mage provide counterspell cover to his (physcial) team while in the Astral?
As an extention to the question, can a mage dispell sustained spells inthe physcial from the astral, eg undo mob mind?

[TheVanguard]

Spells are restricted to the plane they were cast on. If you cast a mana barrier at the physical form of a dual creature it won't be protected from astral attacks. Thus, I'd rule that the same is true for counterspelling. If the enemy casts mob mind on the physical, you need to be there too in order to provide spell defense.

Manifesting yourself (SR4A pg. 193) allows you to do that though, IMHO.

[Dr. Meatgrinder]

True, astral forms can only be affected by Mana spells.  However, a Mana Barrier spell protects against all spells (see, for example, the section on Indirect Combat Spells, p. 204, SR4A).

As far as I can tell, this question is not answered specifically in RAW or FAQ.  However, counterspelling is described as "the magician is actively “jamming” the mana around him" (p. 185, SR4A).  That indicates to me that an astral magician should be able to counterspell just as he would in meat space, as counterspelling serves to interfere with the mystic link through which the spell acts.

Dispelling, however, is specified to be a same-plane thing:  "Counterspelling also allows a magician to dispel a sustained or quickened spell, canceling its effect.  The character must be on the same plane, must be able to perceive the spell she is targeting, and must use a Complex Action" (p. 185, SR4A).

Manifesting (p. 193, SR4A) does absolutely nothing, aside from making you visible and audible.  It is not the same as Materialization, and it does not grant any ability to physically touch/attack/interact with anything.

[TheVanguard]

True, astral forms can only be affected by Mana spells.  However, a Mana Barrier spell protects against all spells (see, for example, the section on Indirect Combat Spells, p. 204, SR4A).

True, but only on the same plane the spell was cast on. See the Mana Barriers section, SR4A pg. 194.
"Magic can be used to create mana barriers on the physical or astral plane [...]. Mana barriers on the physical plane [...] act as solid barriers to spells, manifested entities, spirits and active foci. [...] Mana barriers on the astral plane [...] stop astral movement and impose a visual penalty to astral perception equal to the spell's Force. Astral mana barriers are resistant to astral spells as well as other astral forms, in the same manner as physical mana barriers noted above."

That indicates to me that an astral magician should be able to counterspell just as he would in meat space, as counterspelling serves to interfere with the mystic link through which the spell acts.

That's your interpretation. You could also argue that there is free-floating mana on the physical plane as well that he taps when casting spells, so he will not access the astral plane at all.

Manifesting (p. 193, SR4A) does absolutely nothing, aside from making you visible and audible.  It is not the same as Materialization, and it does not grant any ability to physically touch/attack/interact with anything.

Well, that's not what RAW says. See Manifesting, pg. 193. "If a purely astral form such as a spirit or an astrally projecting mage wishes to interact with the physical plane, she must manifest.
The paragraph goes on to specify that they can't physically interact with anything, but there's nothing in there that forbids magical interaction.
Yes, that would mean that manifesting mages can cast spells at physical targets, and no, I don't like that. But it seems to be RAW as far as I can tell.

[Dr. Meatgrinder]

True, astral forms can only be affected by Mana spells.  However, a Mana Barrier spell protects against all spells (see, for example, the section on Indirect Combat Spells, p. 204, SR4A).

True, but only on the same plane the spell was cast on. See the Mana Barriers section, SR4A pg. 194.
"Magic can be used to create mana barriers on the physical or astral plane [...]. Mana barriers on the physical plane [...] act as solid barriers to spells, manifested entities, spirits and active foci. [...] Mana barriers on the astral plane [...] stop astral movement and impose a visual penalty to astral perception equal to the spell's Force. Astral mana barriers are resistant to astral spells as well as other astral forms, in the same manner as physical mana barriers noted above."

Good point.

That indicates to me that an astral magician should be able to counterspell just as he would in meat space, as counterspelling serves to interfere with the mystic link through which the spell acts.

That's your interpretation. You could also argue that there is free-floating mana on the physical plane as well that he taps when casting spells, so he will not access the astral plane at all.

Yes...hence the qualifying statement, "indicates to me".  The RAW isn't clear on counterspelling vs. plane, except in dispelling.  I interpret, in part because of the specification of plane for dispelling and the lack of specification for spell defense, and in part because of the mystic link business, that spell defense is not plane-specific.  But then I know a number of GMs who want to clamp down on the effectiveness of spell defense, so this may find a different interpretation at each new table.

Manifesting (p. 193, SR4A) does absolutely nothing, aside from making you visible and audible.  It is not the same as Materialization, and it does not grant any ability to physically touch/attack/interact with anything.

Well, that's not what RAW says. See Manifesting, pg. 193. "If a purely astral form such as a spirit or an astrally projecting mage wishes to interact with the physical plane, she must manifest.
The paragraph goes on to specify that they can't physically interact with anything, but there's nothing in there that forbids magical interaction.
Yes, that would mean that manifesting mages can cast spells at physical targets, and no, I don't like that. But it seems to be RAW as far as I can tell.

Except that the manifest astral form is still an astral form, which does prevent magical interaction, whereas a materialized spirit is a dual-natured being.  Manifesting does not specifically grant anything other than appearance and sound.

(And from a game balance standpoint, that's part of why grounding was taken out after SR2 or 3.  Back then, if you had an active focus, an astral caster could use the focus' link to ground a spell cast in the astral into physical space.)

[TheVanguard]

Yes...hence the qualifying statement, "indicates to me". 

Sorry, I didn't word my response very well here. I do understand your intention, I just wanted to provide a counter argument. I agree that the RAW is not clear in this case.

Except that the manifest astral form is still an astral form, which does prevent magical interaction, whereas a materialized spirit is a dual-natured being.  Manifesting does not specifically grant anything other than appearance and sound.

(And from a game balance standpoint, that's part of why grounding was taken out after SR2 or 3.  Back then, if you had an active focus, an astral caster could use the focus' link to ground a spell cast in the astral into physical space.)

Manifesting is such a mess that I don't think that we can really get to the heart of the matter here. That would be something for the FAQ, I'd say. For what it's worth, I run it in my game just like you describe it. 4th ed.'s strict separation of the planes is a great thing and should not be softened up in any way.

[Demerzel]

A historical perspective from an old timer:

Manifesting used to expressly make the manifesting magician vulnerable to mana-based effects in the physical plane.

 “Manifesting characters and spirits, however, are vulnerable to mana-based magical effects on the physical plane.” (SR4 v1.0 FanPro, 184)

An early errata (Available here.) removed that sentence.

p. 184 Manifesting [4]
Change the second line to read:
“Manifesting is a psychic effect that allows an astral form to make itself visible and audible on the physical plane through an act of will.”
Remove the second-to-last line (the one beginning with “Manifesting characters and spirits, however ”)

The interaction of Manifesting astral forms with the physical planes via mana based magical effects was removed with that errata change. The notation appears to indicate this was a change made in version 1.4.