Manual index/Airport page
Ephemeris and daylight
Sunrise, sunset, twilights, sun arc.
Client-side computation of sunrise/sunset times and the three twilights (civil, nautical, astronomical) for the exact airport position. Both the app and the dashboard render it as an animated sun arc with a real-time 'now' marker.
What the twilights mean
- Civil
- Sun 6° below horizon — horizon visible, night VFR rules not yet required
- Nautical
- Sun 12° below — horizon gone, navigational stars visible
- Astronomical
- Sun 18° below — full darkness at the observation level
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All times are UTC. Most aviation rulebooks use civil twilight as the cutoff for night-flying rules.