Invisibility Over Time

[Aermas]

While it's possible to use Permanency Wards & a heap of dragon bone to make things permanently invisible, there's going to be issues when you inevitably need to see the thing that you've now warded. So I'm looking for ways to efficiently & conditionally make something/someone indefinitely invisible. The standard Invisibility spells have very short durations so just making a boilerplate TW Device won't cut it. What options do I have?

It needs to have:
An On/Off condition
Invisibility Superior/Lesser
Invisibility to Sensors
Mystic Invisibility
Self sustaining with no personal PPE spent beyond getting it up & running

[Mersharr]

It's probably cheaper and easier to just get an Amulet of See Invisible than to put an on/off-switch on the invisibility

[Aermas]

Wouldn't Mystic Invisibility make it immune to See the Invisible?

[ShadowLogan]

Bio-Wizardry/Rune Magic are potential options.

There are creatures with the ability to turn invisible without duration (ex. the Brodkill in SB1o, I haven't cross checked other C&P instances), so using Bio-Wizardry would with the right type of creature at the core of a Bio-Wiz device could satisfy what you are looking for.

Circle Magic (in PF) might also work, at least while its in the Circle.

A TW device could be made to be ley line powered, removing the invisibility duration giving it an on/off switch essentially. You lose mobility though (at least not without losing ability).

[Aermas]

I want to create the stereotypical "Hidden City" that's always invisible & undetectable & flies around so people don't walk into it. A bunch of mystic types made it & only a few people would be allowed to bring others to it. Skinning a creature & using Bio-Wizardry isn't something they'd do, though thanks for the suggestion. They are Good Aligned if that helps

[ShadowLogan]

If your looking to duplicate the "Hidden City" trope I would suggest looking at how other "Hidden Cities" in the setting have achieved this like:
-Dwemer (Sp?, WB16)
-City of Brass (WB16)
-Stormspire (WB16, okay not a true City here, but a Tower that teleports around)
-Psycape (WB12)
-the Atlantean/Amazon City in SA1 (WB6)

Granted most of these use dimensional "pockets", but Dwemer doesn't as they rely in part on illusion (not true invisibility) which might be easier to achieve. A TW device that uses Cloud Magic (WB14) that is Ley Line Powered could create a "sky castle" of indefinite duration using an existing spell in that branch of magic, though here you'd be limited to traveling along Ley Lines. While not invisible per say, it might just be dismissed as a cloud(s) that resemble a castle (and making an otherwise undetectable cloud might attract more attention).

Also depending on the altitude (and actual size) this flying city operates at it might be practically invisible anyway, and even if one could detect it would require long range weapons to attack (which could be avoided by steering clear of known territory where they are, like the CS). And even if they could be detected it might not be the best idea to have a City sized object come crashing down into/near one's territory (for example if an Nimitiz Aircraft Carrier was a stand-in for your flying city, and dropped from 10,000m it would impact with the equivalent of 2.3kilotons of TNT of energy, not exactly a Little Boy Nuke's 15kilotons, but someone is going to still have a bad day).

[Aermas]

I found an answer, posting this for anyone else. There is a spell, level 7, Circle of Concealment in Behind the Shadows that does exactly what I was looking for.

[ShadowLogan]

The Spell can also be found in the Palladium Fantasy Main Book (pg 200), though Circle Magic requires physical components, the description isn't clear on what those components might be.

[Aermas]

You know, I always tend to forget that there are differences between the PF spell list & the RUE