Intellego spells that do not target a specific person are not blocked by Parma Magica. While Parma Magica might render you invisible to it, the spell still goes off and detects/senses/etc whatever it was designed to so it is not blocked.
AotH on the other hand would prevent the spell from being able to detect anything at all unless it overcame the AotH, thus completely blocking the spell.
It is a matter of degrees. PM does not stop the spell, but renders you invisible to it if it does not penetrate. AotH completely blocks the spell if it does not penetrate.
Edit for Example: You cast a In(Cr)Im spell to show an image of everything in a room on a mirror.
If there is no AotH, everything in the room is visible except for things protected by Magic Resistance (such as Parma Magica) that it fails to penetrate. The Magic Resistance does not stop it from going off.
If the target room is protected by an AotH, then nothing will be visible unless it manages to penetrate the AotH.
Also take a look at ArM5 p.67 Second Sight, p.113f Magical Senses and HMRE p.53 box New Virtue: Sense of the Mystic.
So there are Non-hermetic magical sense effects ignoring the Parma Magica and other Magic Resistance completely, and these can be integrated with the Magical Senses of Hermetic magic.
(I am not disagreeing with OneShot, just expanding on his post for clarity)
Note that while Second Sight is not affected by Magic Resistance, Magical Senses gained from Hermetic Spells must penetrate Magic Resistance to take effect (p. 114). Sense of the Mystic is an Integration derived from Second Sight, which allows Hermetic magic to ignore Magic Resistance in the same way as Second Sight does on Intellego effects with Target: Sense.
Another interesting path is to Fully Integrate Second Sight into Hermetic Theory (allowing to learn the ability without a Virtue). While this would require two Major Breakthroughs, the effect would be dramatic. Even just a normal Integration (producing a version of Second Sight that was a Hermetic Virtue) would mean that a large proportion of future Magi would have it since it could easily be given just before the opening of the Arts.
Generally Parma will not render you invisible to an InIm spell cast over an area, because it is detecting the species you shed, not yourself. It doesn't stop magic from looking at your footprints either, by way of analogy- once it is not part of your person it is not protected.
"Intellego spells that do not target a specific person are not blocked by Parma Magica."
Maybe, but i would like to know why, because it doesn't seems like that in rules. PM gives Magic Resistance, and Magic Resistances examples say:
"A mind control spell targeted at a group including the maga fails to affect the maga, but may affect other members of the group".
This type of examples suggest than, in a non-specific target spell, Magic Resistance still need Penetration.
For example, something like "detecting all humans in a room while you touch one wall of it".
I don't know for Second Sight, since I focus on Intellego spells and why the AofH suggest than Intellego spells aren't affected by PM
I understand it blocks spells like InIm who detect species (doesn't affected by PM) but the description suggest than all or a majority of Intellego spells aren't blocked by a Parma Magica.
Which also suggests that you could read someone's mind and bypass parma via indirect casting: for example a spell with target hearing to hear the thoughts of those around you then go set next to the person with the parma.
Read HoH:S, p. 61~65 for clarifications and explaining species. There are tons of Intellego spells within the core book that are ether partially resisted or not resisted by Magic Resistance. They do one of:
Magically sense information outside of Parma Magica/Magic Resistance and feed it into one of your mundane senses [used for sensing things that do not create species, i.e. detectable by a mundane sense].
Enhance the information gained from a mundane sense by enhancing/modifying/destroying the species just before they reach the target [seeing through intervening matter is destroying the visual species of that matter before it reaches the eye].
Project the mundane senses to a new location [the species you sense could be sensed with your mundane senses], possibly modified by option 2. Spells in this category use Range: Arcane Connection.
[Explanation with just the Core Book: Magical senses must penetrate if what they are doing is sensing something only detectable by magic and gaining that information on someone/something with Magic Resistance. Mundane senses do not need to penetrate Magic Resistance, even if they are located somewhere other than with the caster or are enhanced.]
Sense of the Lingering Magic is an example of the first. While it would have to penetrate to detect magical effects that you have on you (they are inside your Parma Magica), if you cast a spell affecting the area around you then that is detected completely unresisted by your Parma Magica.
Sight of the Active Magics would be another example of the first. While it would have to penetrate to see the aura of spells on a Magus (the spells are inside his Parma Magica), spells that he has cast affecting the area and objects around him are detected with no problem.
Eyes of the Eagle is an example of the second. It is not providing anything I could not get from my mundane sight. I have to be able to see you, even if you are so far away that I could not make out details normally. It just allows me to see you as if I was closer, by magnifying the species just before they enter my eyes.
Eyes of the Bat is another example of the second category, modifying species gained from touch (air) to auditory. Even if your group played it as under the first category and it failed to penetrate Magic Resistance, the caster would still know someone was there since there would be a strangely Magus shaped blank spot within his echo sense. He would detect all of the air around up to the edge of the Magic Resistance/Parma Magica, then nothing within it. I wonder if the perfectly human shaped blank spot from which nothing is detected is a human? It would actually stand out more clearly.
The Ear for Distant Voices is in the third category. The caster projects their hearing to another location. If the Arcane Connection they are using to cast the spell is to a person, location or item without Magic Resistance, the spell is completely unresisted. However if the Arcane Connection they are using to cast the spell has Magic Resistance (or is to an item worn by someone with Magic Resistance and thus within their Magic Resistance) then the spell must penetrate to take effect. After it has taken effect it is unaffected by Magic Resistance, even if it is attempting to hear someone who has a Magic Resistance high enough that the spell would have not gone off if they were the Arcane Connection because it is collecting the species outside of their Magic Resistance.
The example in my first post [In(Cr)Im showing an image of everything in a room on a mirror] was chosen because using just the core book it could be partially or wholly resisted depending on how it is defined. If you define it as projecting your sense of sight to an Arcane Connection in the room and projecting what you see as an illusion on the mirror (with Creo Requisite +1) than it is resisted or not as option 3 above. Your sight would be at the target location (where the Arcane Connection is) and the image in the mirror would be for others to see what you see. If you defined it outside of the projected senses style (because you don't want to project your sense), then it would only display things that it managed to penetrate. Once you add it the clarifications from HoH: S then it pretty much always going to use Option 3.
Now on to the Aegis! All of these effects that are not normally blocked by Parma Magica/Magic Resistance must penetrate the Aegis to collect anything inside of it. That includes spells which modify the species just before they reach you. So Eyes of the Eagle could magnify your vision of to 12" from the edge of the Aegis but no closer if it did not penetrate the Aegis. Eyes of the Bat would detect nothing past the edge of the Aegis if it did not penetrate the Aegis. A spell to project your vision to an Arcane Connection within the Aegis would completely fail if it did not penetrate the Aegis.
EDIT: Updated post with a clarification on category 3.
I actually wanted to talk about this, since I noticed this while researching for my "Scrying Mirrors" topic.
"Haunt of the Living Ghost" and "Convening the Council" (HP p44) seldom work if the magus needs to penetrate.
The later spell states that the species generated by the image of the magus aren't magical, and thus aren't resisted.
OTOH, Palm of Hearing/Seeing (TtA p80) states that both spells must penetrate to hear/see beings with MR.
As far as I can tell, they fall into your third category: unless the target of the spell as MR, they should not be resisted, allowing you, for exemple, to target a mirror in a council chamber and see/hear from there, without having to penetrate.
EDIT: After further review, I have to revert my answer. Range: AC is a key part of category 3.
The two spells asked about, Palm of Hearing and Palm of Seeing, do not fit into category 3. They are "work around" spells with a range other than AC. If you want to target the mirror in your example to have your sight/hearing from it and not get bounced by MR, then use a project senses spell with Range: AC to the mirror rather than bouncing it through an Intangible Tunnel.
Check with HP p.84 Fingers for Eyes: "This spell must penetrate in order to sense creatures with Magic Resistance.". The spell has T: Room instead of the T:Vision of TtA p.80 Palm of Seeing.
The latter is an ArM5 p,113f Magical Sense, so "must penetrate the Magic Resistance of creatures sensed." The fomer also "must penetrate in order to sense creatures with Magic Resistance."
The argument, that you just see species that are there anyway from a different place, does not waive MR against any of them.
Take a look also at MoH p.101 To See As Though a Plethron Distant, the classical "I just move my point of view" spell, using T: Special based on T: Room. Still, this spell does not allow targeting with R: Sight on thus acquired targets. The reason guessed at is, that the species seen by it are already magically recreated. It is not specified, whether a creature with MR thus watched can resist this spell, but Fingers for Eyes makes this plausible.
Wow not one but two answers I made stupid mistakes on because I was tired and it was late at night. I spent about 20 minutes going back and forth because the two spells did not feel like they fit into the same category but I could not put my finger on why exactly.
It is the lack of Range: Arcane Connection. All of the spells I would consider category 3 have that range and the arcane connection is what is used to center the projected senses with. The law of symmetry, through that AC, is what allows the Magus to project and use his mundane senses. It is the physical anchor.
The first three might have an AC for the first range (the Intangible Tunnel), but then they add another range through it and thus create a "Magical Sense". They are "work around" spells used when the target you have the AC to has Magic Resistance high enough that a normal project sense spell with range AC (category 3) could not penetrate.
To See As Though a Plethron Distant works through Range: Sight, then allows you to see into an area you have no connection to. It is in effect creating a "magical mirror" at a point you can see which reflects your sight and hearing around that point into areas outside of your sight. I am at a crossroads on weather it would require penetration to see things with MR and will have to think about it some more.