KEWAUNEE COUNTY – The two fifth-order Fresnel lenses in the county's two lighthouses were removed June 5 under the order of the U.S. Coast Guard, but the old and valuable lenses won't be in hiding from the public.

The lens removed from the Algoma lighthouse is going to the North Point Lighthouse and Museum on the Lake Michigan shore in Milwaukee. That museum also has a fourth- and sixth-order lens.

The lens from the Kewaunee Pierhead Lighthouse will be close to home. It was taken to the Kewaunee County History Center, where it also will be on display to the public, in a replica of the lighthouse lamp room.

According to the Kewaunee County Historical Society, which operates the history center, the Coast Guard is decommissioning all Fresnel lenses. Not only are they historical artifacts, but they also can be harmed by the near-constant exposure to UV light and harsh elements in a lighthouse. LED lights, which are less expensive and easier to maintain, will replace the Fresnels.

Compared to a conventional lens, a Fresnel (pronounced "freh-nel") uses a series of stepped pieces of glass to capture and refract light, allowing it to be thinner and more compact while focusing and projecting its beam. Its first use was in the Cordouan lighthouse in France in 1823. 

Kurt Fosburg led the team that moved and cleaned the lenses. Fifth-order lenses are valued between $150,000 and $300,000, according to the historical society, and the one from Kewaunee Pierhead dates to the early 1890s.

Contact Christopher Clough at 920-741-7952, 920-562-8900 or [email protected].

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This article originally appeared on Green Bay Press-Gazette: Fresnel lenses gone from Kewaunee County lighthouses, going to museums