Choosing the right exposure time depends on several factors:
- Camera sensor: Larger sensors with better noise control handle longer exposures.
- Lens focal length: Wider lenses allow longer exposures without star trails; telephoto lenses require shorter times unless tracking.
- Mount and tracking: Fixed tripods limit exposure time; equatorial mounts or star trackers let you go longer.
- Sky conditions: Light pollution and moonlight can limit useful exposure length.
Start with the 500 Rule for fixed tripod shots, then adjust based on your gear and conditions. Experiment gradually to find the sweet spot where detail and noise are balanced.
