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Light characteristic (wikipedia.org)
60 points by altilunium on Feb 9, 2024 | hide | past | favorite | 7 comments


I'm intrigued by the "Flørauden seamark in Norway and its light characteristics" chart in this article. It has a circle with segments of different colors around the light, with different descriptions. Does this mean that the Flørauden light looks different depending on which angle you look at it from? (i.e. that it's many directional lights)

That could help navigate, as one could check what angle they are with respect to the light; but I didn't know it was done.


Quite a few lighthouses have this characteristic, it’s usually one rotating light, and coloured glass for the different sections. The idea is that you can safely approach the lighthouse in the “white section” only, the others are for guidance: green to your right and red to the left (at least over here in Europe where we use IALA A, in America it’s the other way around). When you can see white, it should mean you have a clear way towards the lighthouse. Then, as you get nearer to your port, you get again a green light on your right and red on the left, and that’s the right way in.

As for where you’re with respect to any light, what you need is chart and compass. Usually there should be only one light with a certain characteristic in the area, which you can then track down in your chart. With a compass you get a bearing, and you now know you’re somewhere on a line. Find another lighthouse (or other landmark), get the bearing, and you can know where you’re fairly precisely!

(Source: I’m getting my sailing license :-)



Appears to be exactly that. Note that the white light segments (shown in yellow and slightly extended in radius on the chart) are always placed between green and red segments as you move clockwise - the white segments are ‘safe channel’ indicators of some sort.


You might also find moiré-effect navigation beacons interesting, like the one that Tom Scott visits here: https://www.youtube.com/watch?v=d99_h30swtM


For everyone interested in this:

https://geodienst.github.io/lighthousemap/


These abbreviations and definitions seem very similar or identical to the charts I’ve used for sailing in coastal waters of the United States.




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