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Astro Photography Calculator

Calculate optimal exposure times for pinpoint stars and star trails

About Astro Photography

Astro photography requires precise calculations to capture stunning images of the night sky. This calculator helps you determine the ideal exposure settings for both pinpoint stars and mesmerizing star trails.

The calculator uses two important formulas:

  • NPF Rule: Calculates the maximum exposure time for sharp, pinpoint stars before star trails appear
  • Star Trail Formula: Determines the optimal exposure time to create beautiful star trails of your desired length

Enter your camera and shooting parameters below to get precise recommendations for your next night sky adventure.

Note: These are starting point recommendations. Actual settings may need to be adjusted based on your specific conditions:

  • Light pollution levels
  • Moon phase and brightness
  • Camera's high ISO performance
  • Atmospheric conditions

Astro Photography Tips

For Pinpoint Stars

  • Use a sturdy tripod and remote shutter
  • ISO 1600-6400 depending on light pollution
  • Manual focus using live view zoom

For Star Trails

  • Use multiple exposures for stacking
  • Include interesting foreground elements
  • Use lower ISO (400-800)
  • Consider using the stacking method: multiple shorter exposures combined in post-processing
  • Include an interesting foreground element for composition
  • Point your camera toward the north star (Polaris) for circular trails
  • Use a lower ISO (400-800) to reduce noise in longer exposures
  • Make sure your battery is fully charged or use an external power source

Happy Space Shooting