Long-exposure shots where stars look like circular paths; great for representing time or movement.
If you are taking your own "Sky picture," you’ll likely shoot at a much higher resolution and crop down.
To avoid "star blur," divide 500 by your lens's focal length to find your maximum shutter speed (e.g., a 20mm lens = 25-second exposure).
Use ISO 1600–3200 for crisp stars without excessive digital noise.