Please see RoP:M:
*P. 73 "True Sight of the Air" which is a common powers for cats.
*P. 65 "Shriek of the Impending Shafts" which is a power for the White Stag of the Wood
Funnily enough, those powers are hermetic spells that somehow succeed in giving magical senses to magical animals. You're reading things wrong, buddy.
RoP:M p.73 describes Magical Powers for Magical Lineages of Cats, who even have oral traditions (RoP:M p.70), hence Intelligence, and should qualify as persons in the core book.
RoPM p.64f The White Stag of the Woods has Intelligence, so should qualify as a person too. Anyway, an inborn Magical Sense would also come with an inborn Common Sense (A&A p.31) able to process it - which is quite different from an Hermetic spell or effect applied after birth.
You're grasping at straws for argument. An animal with Intelligence might be able to be targeted by Mentem, but its still an animal, not a person. Whatever.
Can a Bjornaer in Heartbeast form be successful target of a magical sense spell? Hermetic magic cannot distinguish their minds from animal minds with Cunning.
Ultimately, saying the rules don't allow it for animals is a house rule, and the OP asked for RAW only. Core RAW gives rules for how they can be granted to people. Core RAW does not say they cannot be given to animals; rather, it is silent on granting magical sense to animals or other non-people things. If Hermetic magic can give such a sense to a Bjornaer in Heartbeast form, then it can grant magical senses to things it can only recognize as having animal bodies and minds; but the core book isn't explicit that these work on Bjornaer in Heartbeast form, though such a Bjornaer is probably still considered a person by those of us reading the rules.
It rather gives rules granting Magical Senses to persons. There are no rules granting Magical Senses by Hermetic spells or effects to other beings than persons. So "by RAW" other beings than persons cannot receive Magical Senses by Hermetic spells or effects.
Does a Bjornaer change from person to not-a-person, if she assumes Heartbeast form? I should not think so.
Certainly the Bjornaer does not lose her Intelligence, her soul and her (A&A p.31) reason, as she turns into her Heartbeast.
More precisely, we have (ArM5 p.91f Bjornaer: The Heartbeast):
Hermetic magic is unable to tell whether an animal is actually a Bjornaer, and the same applies to most other kinds of magic. <...> Spells already in effect before the transformation remain in effect, however.
So clearly, Magical Senses cast onto a Bjornaer remain in effect after she assumes her Heartbeast shape.
This also makes very good sense, as she retains her immortal soul and her reason.
If a magus casts a spell bestowing Magical Senses onto an animal, he does not see directly, whether that spell works. If that animal is a Bjornaer in Heartbeast shape, she knows enough of her animal form to pretend being unaffected, or even confusion under weird sensory input: so the magic doesn't tell the magus that she is a Heartbeast. In a similar way, casting ArM5 p.118 Opening the Tome of the Animal's Mind works on a Bjornaer Heartbeast if it penetrates - but cannot find reason and soul in her mind.
This is a very good argument, that for Magical Senses to work on their recipient, they not only need to be given by magic, but also require specific prerequisites: like sufficient reason to adapt to new information input via the existing senses.
In the case of the Heartbeast, these prerequisites themselves cannot be checked by Hermetic magic.
Okay, this has gone into many fascinating directions, and I am very happy with the responses. The point of the original question was "can I replace this enchantment with a circle spell, it would let me make updates to the device." "also the need to penetrate is weird, is it needed for a mundane form of sight?"
I was of the opinion that if you give a thing, statue, painting or whatever else an discernable eye or eyes, you can hang the spell/effect on the implied or anthropomorphized object's sight.
Going back to your initial question, I think one clarification I'd make is that a circle spell doesn't necessarily affect the circle itself, but the targets within. So you wouldn't go about granting a circle senses, as much as you'd grant senses to whatever is inside your circle, to which you'd need an arcane connection to for follow-ups. I understand the rationale towards saving seasons for creating a circle spell like that especially if you want a lot of "cameras", but you'll face other issues like broken circles and warping that you may not necessarily want to deal with by skipping the enchantment phase.
Also, as a side consideration, while I think the stone watchmen's enchantment is valid, I would probably go about designing this differently because it relies on two effects rather than one effect. It essentially uses an Intellego Imaginem 15 spell (Base 1, +2 Sun, +4 Vision) followed by a Creo Imaginem 15 (Base 1, +2 Sun, +4 Arc) to substitute for a power that could be designed as an Intellego Imaginem 20 effect (Base 1, +2 Sun, +4 Arc, +1 creo requisite to display the image obtained). If the magi is sufficiently skilled in Imaginem, he might be able to pull a single enchantment as a lesser enchanted device, and skip the opening. Even without that, unless he's very weak with Creo, it's rare that adding 5 to your lab total target will increase the time necessary by more than 1 season... which would be spent on the secondary effect anyway, at a higher vis cost.
Doing this as a single enchantment would also open up the possibility of having an arcane connection in whatever device (probably a mirror) that could be changed to another arcane connection, thus letting you move the "camera"'s location, which is your objective here.
See the thing is my magi could spont that with a ceremonial casting, if need be.
I could carve a ring into the stone our covenant wall, plonk a statue down and spend a few hours casting.
Our game is a little fast paced sometimes since we almost never see things coming and I (my mage) can't even squeeze out a few seasons to create my talisman.
Secondly, I'd really like to see what a bit of warping can do.to a stone beasty.
I actually had not thought on doing the entire thing as a circle but hey, if it works then that is awesome.
Sometimes when asking things on this forum people get a flood of replies of the like of "no, sorry, you can't do that because [insert arrays of references and interpretations here]". Sometimes you'll get and share the logic behind them and then, well, ok, you probably can't do that (and hopefully people replying can have suggested a few other ways to do that anyway). Some other times you can shrug and resort to the "well people here really have an encyclopedic knowledge of quite a lot of books indeed, but this is supposed to be about magic, not logic, so why the hell can't I make up a base level to do that and move on". I don't read much above to make you change that first opinion you had on this thread, so I'd keep it if I were you.
Most ST's don't like their magi to bypass spending time and V on making a permanent item with a circle spont spell.
I wrote the post to figure out if and or why the device was written in that way, since enchanted items has to be reforged by someone with a virtue to update it.
While a circle spell can be applied instead and updated whenever you get a better casting total or a specialized caster.
Then things got esoteric.
Oneshot came out and schooled me on the spell
Then temprobe cleared things up for me.
Many thanks to all the magi who took some time to assist and deliberate this topic.
Even the bit with the owls.