Sub-Exposure Length Calculator

Determine optimal sub-exposure length based on your sky conditions, filter type, and camera characteristics.

Input Parameters

Camera

Read Noise (e⁻)

Full Well (e⁻)

Telescope

Focal Length (mm)

Aperture (mm)

f-ratio: f/5.6

Sky Quality (Bortle)5 - Suburban

Filter Type

Target Brightness

Recommended Sub-Exposure

40s

Recommended exposure length

28s

Minimum

56s

Maximum

Standard conditions for astrophotography.

Quick Tips

Shorter subs = more data points, easier to discard bad frames, but more read noise.

Longer subs = better SNR per frame, less read noise impact, but risk of satellites/clouds.

These are starting points - adjust based on your actual results and conditions.