My wife and I relax before bed a few nights a week in our old outdoor Jacuzzi, it eases painful knees. It is heated to 102 degrees, and I usually bring a light out just in case we have coyotes prowling around while out beagle is sniffing around out back, usually a P60 or better.
Tonight for some reason I brought my Klarus ST10 (single AA) and set it on the step. At some point I picked it up and put it on Medium, just above the surface of the water facing up.
What a great light show! Even my wife (you know how she loves my flashlight hobby) was fascinated with the rising smokey swirls illuminated by the beam. I'm going to have to try to photograph or video this, because it is one of the coolest things I have done with a flashlight. It was a perfectly clear and dark sky, and the conical beam made images like you would see in a Disney movie of a spirit departing from this world.
No, I wasn't smoking anything, honest. Guess you had to be there.
But I encourage you, if you have an outdoor jacuzzi, give it a try!