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Nautical Twilight Schedule

Generate a yearly streetlight operating schedule for any location. Returns daily nautical dusk (lights ON) and nautical dawn (lights OFF) times.

Default location: US Census Mean Center of Population (2020) — Hartville, MO. Streetlights turn ON when the sun drops to −6° elevation (end of civil twilight) and OFF when it rises back to −6° (start of civil twilight).

Phase Calculator

Upload a CSV with coordinates and timestamps. Each record gets tagged with sun elevation, twilight phase, and streetlight status.

1. Upload CSV

Drop a .csv file here or

Maximum 2.5 million rows

2. Map Columns

Confirm which columns contain your location and date/time fields.

3. Processing

Splitting and processing your data...

4. Download Results

Download CSV

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