Professor Xiong’s Lecture: The brighter the fishing lamp, the more power, the farther it shines? (2)

1. The brighter the metal halide fishing lamp is, the greater the power is, the farther it will be.
One might say, of course it is, the brighter it gets, the farther it gets! That’s why lighthouses are lit very high. There is some truth in this statement, but not all of it. Because the earth is round. We’ve all had this experience at sea, where you can see the mast of a ship from a distance, and as you get closer and closer you can see what’s below the mast. We are also familiar with the so-called “stand tall, see far” rule of thumb. So in a way, “If the light hangs high, it shines far” is true. That’s why lighthouses are tall towers, because the higher the light is, the farther it shines!

Let’s discuss the relationship between the height of the lamp and the distance it illuminates. See the figure below

The earth is round and a circle represents the earth.
Enlarge it……

Zoom in further……

The arcs in the figure represent the sea level, the positions marked 1, 2 and 3 indicate the position of the hanging lamp, and the lines close to the horizontal indicate the light. As can be seen from the figure, the higher the position of the lamp above the sea level, the greater the area of the sea level will be illuminated. And the illuminating distance is not proportional to the hanging height.
After preliminary estimation, the hanging height and illuminating distance can be expressed as follows:

Where l represents the radius of the illumination range; R is the radius of the earth, generally 6400 kilometers; h is the height at which the lamp is suspended. Therefore, the height of the suspension and the radius of the illuminated area can be estimated in the following table:

Here we get the first result of our discussion: instead of the light shining farther away, the area of the sea where the light shines has a maximum value, depending on where the light is hung. The higher you hang it, the larger the illuminated area. Generally, the suspension height of the BT180  1500w MH fishing lamp is 5-10 meters, so the maximum radius of the light can illuminate the sea is 5-8 kilometers. No matter how bright the lights are!!
Here’s a joke: Don’t just try to increase the brightness and height of the sea area, the sun is high enough and b right enough, it can only light up half the world!!