flashing light
Quick Summary
Lighthouses use rhythmic flashing or eclipsing lights to identify themselves to mariners. This unique pattern is called the light's "character," and the time it takes to repeat is the "period." International agreements, managed by the International Association of Marine Aids to Navigation and Lighthouse Authorities, limit the number of distinct characters available.
Common patterns include:
* Flashing lights: A single flash repeated at regular intervals.
* Group-flashing lights: Groups of two, three, or four flashes, separated by short eclipses, with a longer eclipse between groups.
* Occulting lights: Lights that are normally on but momentarily extinguished.
* Isophase lights: Alternating eclipses and flashes of equal duration.
These visual signals, along with distinctive structure colors, help mariners navigate and avoid hazards.12
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