Any sailors here? How can a 243ft. Lighthouse be visible 44 miles away?
(en-wikipedia-org.turbopages.org)
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The calculation is: visible distance to horizon of the lighthouse + visible distance to horizon of the eye above the deck above the waterline.
distance = 1.17 * square root of height in feet
for lighthouse = 1.17 * sqrt (243) = 1.17 * 15.58 = 18.22
for man on deck, est 45 feet = 1.17 *sqrt(45) = 7.85
total = about 26 miles
A bit short. But then we need to account for refractive effects that might bend light. I don't have a computation for that right now. But atmospheric lensing can happen and extend range.
If the light beam is horizontal it doesnt work according to the curve model.
I want to see photo or video of 40 miles out.
To see the angle of the light.
Or personal testimony.
It's not the full model. What looks to you like a straight beam of light is actually not that at all. It can be refracted, which in effect curves it. Nearly all light, even laser beams, is the radiation of wave emissions from a source. The nature of waves is that they spread as they travel. A laser spreads little but it does spread. A lighthouse beam in reality is somewhat spreadier than you might think. An ocean is colder than the air above, usually. This causes the air near the ocean to be denser; the air a little above gradually less dense. This forms a lens that can bend light beams. It's like the desert mirage effect caused by hot ground and air at a different, graded, temperature.
In my case I see mirages too but it's from the cheap whiskey.
Thats a good explanation. Thanks.
Refraction.
I still want to see photos or video or descriptions from sailors but appreciate your response.
Cheers.