star trail photography
ONE: The Earth is rotating. This means you can photograph star constellations, but after about 15 seconds, you will start to get blurring in your stars because of the movement of the Earth.
TWO: You should know a couple of constellations before you go out: the Big Dipper and Orion are the two I use to orient myself.
Source: Star Trail Photography Tips – PictureCorrect:
