How to get "tilt" to ground angle from an actor

[DExUS5]

Hello guys,

Imagine a bottle, and when you tilt it lets say 95° to the ground and once that is acomplished a particle emitter will start, simulating flow of water.
How can I calculate the angle of the actor to the ground ? so I can activate the particle emitter at the set angle?

[SouthBot]

GetActorRotation