A lighthouse is a structure located on a coast, harbor, or river to guide the direction of a ship.
Most lighthouses are shaped like towers, with a system of lenses at the top of the tower that shines light out to sea.
Before the advent of electricity, fire was often used as a light source.
A lighthouse consists of a luminaire and a tower.
The tower can be constructed with a variety of building materials, mainly to adapt and resist harsh natural conditions such as wind and waves, to maintain their stability and durability.
The height of the tower to adapt to the light range requirements.
The luminaire is composed of two basic parts: the luminaire and the light emitter.
Modern lighthouse light-emitting energy mainly uses electricity, the luminous body center of the luminous device is located in the focus of the spotlight lens.
And the light source radiation is spherical light through the spotlight lens into a certain diffusion angle of the parallel beam.
The range of the lighthouse can reach about 30 nautical miles, and the intensity of light can reach hundreds of millions of candles.
The light has a flash, lightning and light and dark light, etc. Light color has red, white, or green, white.
Usually red and green light indicates the presence of obstacles within the light arc.
The practical use of the lighthouse
1.Escort lighting
The lighthouse is a kind of tower-shaped luminous beacon built near the key part of the channel, a fixed navigational beacon, whose basic function is to guide the ship's navigation or indicate the danger zone.
Often used to mark the dangerous coast, dangerous sandbar or reef and the channel leading to the port mouth.
2.Geographical coordinates
Along with the rapid development of science and technology, the establishment of radar transponders, DGPS system, and AIS ship automatic identification system integrated navigation system.
The navigation role of the lighthouse is increasingly weakened, and navigation value is decreasing, but it has a potential historical and cultural value, and has become a good attraction.
3.Military defense
The lighthouse is said to be a beacon on the sea, and it was also used for military purposes in the past, to carry out sea defense watch and prevent smuggling.
Generally, there are also forts, castles, and other defense facilities near the lighthouse.
4.To declare sovereignty
In disputed waters, lighthouses, posts, and boundary markers are often used as a symbol of sovereignty.
