Find the exact start and end of astronomical twilight — when the sky is dark enough for deep-sky observation.
Enter your values below
Your geographic latitude.
Your geographic longitude.
Date to calculate astronomical twilight for.
How this calculator works
Calculates the period when the Sun is between 12° and 18° below the horizon, providing fully dark skies.
Common questions about this calculator
These calculators are for informational purposes only. While we strive for accuracy, results should not be used as the sole basis for important decisions.
