[Alrician]

I have a few questions about astral projection. More specifically, I'm trying to determine what an astral projected mage can do on an action site (e.g. a corp mage reinforcing an HTR team).

According to CRB, it is not possible for astral projecting magicians to cast spells on non-dual-natured beings. A few questions arise from this.

First question: What qualifies an awakened Runner to be dual-natured, other than astrally perceiving or projecting themselves? A sustained spell? An activated focus?

Second question: Can area-of-effect mana spells affect runners that are only active on the physical plane? Like stun ball or mana ball?

Third question: Can a projecting magician assign a target to a manifested spirit that is only present on the physical plane? Two explicit examples: can a Spirit of Men be instructed to heal someone who is mundane using healing spells? Can a Spirit of Fire be ordered to attack a mundane Runner?

Fourth question: can a projecting mage use the clairvoyance spell? If so, does his view become normal or astral?

[autXautY]

A metahuman is generally only going to be dual-natured when astrally perceiving. I think astral projection is more like being 2 separate but connected single-natured things, a physical body and an astral spirit, but that's a bit semantic. There might be drugs that make people temporarily dual-natured.
Manifested spirits, dragons, ghouls, vampires, many paracritters, and such are all also dual-natured.
An activated focus is itself dual natured, but the person using it wouldn't be.

I believe that mana spells cast from the physical plane affect things on the physical plane, and mana spells cast from the astral plane affect things on the astral plane

A manifested spirit isn't only present on the physical plane, they're dual natured. They can be given orders by an astrally projecting mage just fine, and can affect the physical world just fine. The only limit would be that the mage might have difficulty identifying targets on the physical plane (identifying humans would be possible, though need assessing to identify who you're ordering the spirit to attack/heal. But ordering them to attack a drone would be hard since the mage couldn't really detect the drone)

I think if you use clairvoyance while astrally projecting you would be able to see at a distance with astral sight, but I'm not really sure

[MercilessMing]

I believe that mana spells cast from the physical plane affect things on the physical plane, and mana spells cast from the astral plane affect things on the astral plane

That's right.  The core rulebook doesn't do a good job of covering topics related to the astral plane, and didn't clarify anything to my knowledge in Street Wyrd.  I'm going to be using knowledge from previous editions, so there's a possibility I'm wrong but someone will correct me if I am.

While spells affect only the physical or only the astral plane, they have a form that exists on the astral plane.  So, while an astrally projecting mage can't fling spells at opponents that are only on the physical plane, they can perform counterspelling. 

Second question: Can area-of-effect mana spells affect runners that are only active on the physical plane? Like stun ball or mana ball?

Yes, if the spell was cast on the physical plane. 

Third question: Can a projecting magician assign a target to a manifested spirit that is only present on the physical plane? Two explicit examples: can a Spirit of Men be instructed to heal someone who is mundane using healing spells? Can a Spirit of Fire be ordered to attack a mundane Runner?

It's not clear in 6th edition whether materialized spirits are dual natured or not.  In older editions they are, and I play them that way, but Materialization doesn't state that it makes a spirit dual natured.  Yes, a projecting magician can command a spirit to target something/someone that only exists on the physical plane.  People and things are visible from the astral, just shadowy and insubstantial.

Fourth question: can a projecting mage use the clairvoyance spell? If so, does his view become normal or astral?

Yes, and he views the astral.


Here are some things projecting magicians can do:
Recon
Manifest, and communicate with their team about things on the astral
Counterspell
Fight opposing spirits and other astral entities
Summon spirits to:
 - target things on the physical plane
 - obey the commands of another team member
 - sort of indirectly cast spells on the physical plane, by summoning a spirit of Kin and choosing the innate spell optional power and commanding its use

[Xenon]

assign a target to a manifested spirit that is only present on the physical plane?

A manifested spirit isn't only present on the physical plane, they're

A wholly astral entity (like a projecting magician or a critter with the astral form power, like a spirit) that manifest will still be a wholly astral entity without an actual physical body.

Are you both perhaps thinking of Materialization?

[Dreamwalker]

I believe that mana spells cast from the physical plane affect things on the physical plane, and mana spells cast from the astral plane affect things on the astral plane

I was wondering if this strict separation applies to the spell Mana Barrier. Its effect seems to impact the astral plane, even if it the spell is cast in the physical realm.

Mana barriers on the physical plane [...] act as solid barriers to spells, manifesting entities, dual-natured entities, spirits, and active foci.

This section is explicitly referenced in the spell description and the named elements are not specifically required to be present in the physical realm. Also, the spell itself states that astrally projecting mages can't get through without requiring the mana barrier to be cast on the astral plane.

[Xenon]

This might be related: https://forums.shadowruntabletop.com/index.php?topic=31767.msg541957#msg541957