The most ideal location to shoot the night stars would be in the darkest most remote places away from bright city lights. This shot was taken in the countryside of northern Mongolia just below Russia. In cities, it is difficult to capture the night stars due to light pollution. Light pollution refers to too much city lights in any given town that reflects into the night sky which in a way ‘hides’ the stars.
In this shot, the shutter was opened for 30sec. You can tell some of the stars are stretched a tiny bit due to the rotation of the earth. A better exposure would be for 25sec.
If there is a moon in the sky, it will also affect astrophotography as the long exposure for the star will certainly overexpose the moon. Even if the moon is not is the frame, a full moon would certainly brighten up the entire night sky.