How can I see a star behind a mountain range? Do I move apart from it and up? Could some explain what I need to do to see a star that, from my point of view, is behind a mountain:

Obviously, if it's one mountain, and not a very high one, I can just climb it to see what's behind. But what if it's a mountain range or a very high mountain?

Intuitively, I know I can move away from it to change the angle, and see the star. But what's the math behind it? And how does going up (or down, maybe?) help?
Moving away will help. If the mountain is very steep, and you are standing right next to it, you can only see objects that are directly above or behind you. Example: if the mountain is 100 ft tall, and you move 100 ft away, then you can see objects in the sky that make a 45 degree angle off the horizon. Angle = inverse tangent (mountain height / distance from mountain)