Nidingen

Nidingen is a Swedish Kattegat sea area skerry with a lighthouse station. It is located in Onsala parish in Kungsbacka Municipality in the province (landskap) of Halland. The island has with its surrounding reefs always posed a danger to shipping. The three lighthouses on the island, one of which is active, are today protected as heritage buildings.[1][2][3] The island is also a nature reserve with a birding station and hostel, famous for large populations of different bird species.

Nidingen lighthouse
Nidingen

Location	Nidingen, Kungsbacka Municipality, Sweden
Coordinates	57°18′9″N 11°54′2″E
Tower
Constructed	17th century (open fires) 1834 (twin towers) 1945 (new tower)
Construction	reinforced concrete
Automated	1979
Height	23,5 meters
Shape	round concrete tower
Markings	white, black belt
Power source	electricity
Operator	Swedish Maritime Administration (Sjöfartsverket)
Fog signal	(2) 30s
Light
First lit	17th century
Focal height	25,4 meters
Lens	3rd order dioptric Fresnel lens
Range	22 nautical miles
Characteristic	Fl(1+2) WR 27s
Sweden no.	SV-7443
Nidingen twin lighthouses
Constructed	1832
Construction	natural stone
Height	19 m (62 ft)
Markings	grey
Power source	bituminous coal, rapeseed oil, kerosene
Heritage	governmental listed building
First lit	December 1834
Deactivated	1946
Focal height	20.4 m (67 ft)
Lens	third order Fresnel lens (1846–)
Characteristic	Exting (1946–)

The province of Halland and Nidingen was ruled by Denmark until the Second Treaty of Brömsebro 1645. The Danes had lit primitive navigation fires on the island before, and also built a "vippefyr", but now it became one of Sweden's earliest light stations. In the 18th century, the vippefyr was replaced by fires placed on stone cairns, which in turn were replaced by two new stone towers in 1834. They were built even higher in 1847 and were equipped with lanterns and fresnel lenses. In 1884, the colza oil lamps were replaced by kerosene lamps with improved luminosity. The historic lighthouses was in use until 1946 when a new modern tower was completed. The lighthouse was electrified through a connection with cable from the mainland.

In the 1960s, the lighthouse's lens equipment was electrified. In 1973, an automatic rotation of the lens was installed around the clock while the lighting of the lamps was controlled by photocells. From the turn of the year 1978–79, Nidingen lighthouse became fully automated and unmanned. It was reported several times in the 2000s that the lighthouse could be deactivated when it was no longer considered necessary for shipping,[4] but it remained in use. In 2019 it was reported that the Swedish Maritime Administration, Sjöfartsverket, plans to convert it to be powered by solar cells.[5]

Wind observations from Nidingen is reported daily in SMHI Shipping Forecasts.