Light House Cyclopedia

Question 12：Selection standards of the characteristics of light

A:
1. Selection standards of the characteristics of light:
(1) The neighboring lighthouses must have different characteristics of light. It aims to prevent from confusion and misleading guide.
(2) When the characteristics of light are the same on the two sides of the embankments, color masks should be added onto the lenses to differentiate between each other.
(3) When lamps are equipped with different illuminants, change or measurement between light and dark should be distinguished.
(4) Light flashing time should match the sense of light of your eyes.

2. Types of lights (Light identification):
(1) Fixed light ( F ): A continuous or uninterrupted beam of light.
(2) Occulting light (Oc): A light eclipses and shines at regular intervals, with the longer duration of light than duration of darkness. The lights consist of Single-occulting light, Group-occulting light, and Composite group-occulting light.
(3) Isophase light (Iso ) ： With equal intervals of brightness and darkness.
(4) Flashing light (Fl): total duration of light shorter than total duration of darkness. The lights comprise Single-flashing light, Long-flashing light, Group-flashing light and Composite group-flashing light.
(5) Quick light (Q): with repetition rate, flashing either 50 or 60 times per minute. The lights consist of Group quick light, Interrupted quick light, and Continuous quick light.
(6) Very quick light (VQ): with repetition rate, flashing either 100 or 120 times per minute.
(7) Ultra quick(UQ): with repetition rate, flashing 240 to 300 times per minute. The lights comprise Interrupted ultra quick light, and Continuous ultra quick light.
(8) Fixed and Flashing light (FFL): A group of lights consist of fixed light and brighter flashing light.
(9)Morse (MO (U)): This light shows short flashes and a long flash, which is equivalent to the letter "U" in Morse code.
(10) Alternating (AL): An alternating light shines with different colors by turns, and exercises caution by changing light colors.

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