It doesn't really matter as long as the light from the light it is controlling (or some other artificial source) isn't shining on it in a way that will confuse it. Often you can either move or put a small shutter (or tape) to block off the unwanted interference.

Thanks for your return. My sensor is pointing north and my yard light turns on too early, so I thought a different placement of the sensor might balance out the cycle.

Jerry

You can try (also check to see if it doesn't in fact have something partially obscuring the sensor or if there isn't some adjustement that can be made.