While there are many hundreds of operating lighthouses along sea and lake shores in the U.S., only 85 cast and concentrate their beams through a Fresnel lens. And fewer still, just fifteen (including our own St. Simons Lighthouse) do so with an authentic, third-order Fresnel lens. Fresnel lenses are categorized by order depending on their size and focal length.
Pronouced “freh-nel,” these remarkable optical lenses were developed around 1821 by a young Frenchman, Augustin-Jean Fresnel. Before then, lighthouses typically used oil-burning lanterns and a series of reflectors to produce a relatively limited light beam. Fresnel developed a central lens surrounded by prisms to refract, reflect and dramatically increase the intensity of the resulting horizontal beam of light.
Coastal Georgia Historical Society
St. Simons Island Lighthouse Fresnel Lens
The original St. Simons lighthouse used a third-order Fresnel lens beginning in 1857. The lens was removed prior to the tower’s destruction by departing Confederate soldiers in 1861, yet what happened to that first lens is unknown. The current St. Simons lighthouse was constructed in 1872 with a second, third-order Fresnel lens. The lens carries the mark of its maker, L. Sautter. Louis Sautter is the French engineer who made improvements to Fresnel's design and for a time supplied half the lenses used in American lighthouses.
At night, ships navigating our coastal waters can see the brilliant beam of the St. Simons Lighthouse from up to 20 miles away. The white light is punctuated by one strong flash every 60 seconds. This flash pattern identifies our lighthouse for mariners.
For twenty years, the lens has been maintained by members of the U.S. Coast Guard Auxiliary who carry out weekly inspections and system checks.
This month’s images, from the archives of the Coastal Georgia Historical Society, show the upper “beehive” section of the third-order Fresnel lens of the St. Simons lighthouse and a photo, circa 1994, of Coast Guard Auxiliary volunteers (left to right) Cpt. Burney Long, Bob West, Jeff Cole, and Bill Wallace.
