boogeyman has some good information. I have heard of the atmospheric reflection effect.
Checking from the opposite direction would do the same thing that triangulation would, and that is, it would either reveal or eliminate the reflection effect.
But triangulation is the way to absolutely determine where the glow spot is, if it's not some kind of illusion, whereas there are ways, such as has been mentioned, of light doing funny things which make them appear to be something which they actually are not.
And also appearing to be in a place other than where they actually are emanating from. Kind of like an mirage in the desert usually appears to be other than where and what it really is.
If conditions do arise where it will appear again, please don't let it lead you on a wild goose chase! If a person is "following" an optical illusion, he can wander all over the place, but if
is something which
can be triangulated, then at least you can let other people know where you are supposed to be going, and if an accident should happen, then they would know about where you are, if you don't return in a reasonable amount of time. That should always be a consideration beforehand.
Be level-headed about it, and don't do anything that you will be mad at yourself for later!
