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Camera Sensor

Lens Settings

Target Declination (optional)

Stars near celestial poles move slower, allowing longer exposures

Point Stars (No Trailing)

Recommended Max

14s

NPF Rule

500 Rule

25s

Less accurate

400 Rule

20s

Conservative

Intentional Star Trails

For circular star trail photography, use these exposure guidelines:

  • Short trails: 30m - Subtle movement
  • Medium trails: 2h - Clear arcs
  • Long trails: 4h+ - Dramatic circles

Tip: Stack multiple shorter exposures (e.g., 30s × 200) to reduce noise and allow for gaps if needed.

Understanding the Rules

  • 500 Rule: Simple but often produces slight trailing on high-res sensors
  • NPF Rule: More accurate - accounts for aperture and pixel density
  • Crop Factor: 1× (sensor width affects field of view)
  • Pixel Pitch: 5.9µm (smaller = more sensitive to trailing)

Astrophotography Tips

  • Use the widest aperture available (f/1.4-f/2.8 ideal)
  • Set ISO high enough to capture stars (typically 1600-6400)
  • Use manual focus set to infinity (∞) and fine-tune on a bright star
  • Shoot in RAW for better post-processing flexibility
  • Consider a star tracker for longer exposures without trailing