Astrophotography involves some tricky math, and small errors can lead to blurry stars or poor exposure. Here are a few common pitfalls:
- Ignoring the 500 Rule: Using exposure times too long without a tracking mount causes star trails. Remember: Max Exposure (seconds) ≈ 500 ÷ focal length (mm).
- Misunderstanding Focal Ratio: The focal ratio (f/number) = focal length ÷ aperture diameter. A lower f/number means more light and shorter exposures.
- Overestimating Exposure Time: Longer exposures gather more light but also more noise and risk star trailing if tracking isn’t perfect.
Double-check your calculations before you shoot to save time and get crisp, clear stars.