why do they do that
In: Earth Science
As well as making it clear what’s a lighthouse and what’s just a normal light, but by introducing the rotating lens system you can do other things with the light such as making it appear to flash at different speeds, or even different colours.
By doing this, you can help mariners figure out just which lighthouse they’re looking at. To take two local lighthouses from my area, one of them flashes a red light for one second, then off for four seconds, and then repeats the cycle.
Another lighthouse further up the coast gives three white flashes even ten seconds.
By having these characteristics marked on charts, mariners are able to tell where on the coast they are at night. It’s less important nowadays that modern electronic navigation aids are available, but in years gone by it was invaluable.
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