Illuminating the Night Sky
with the 4th Order Fresnel Lens
The Light Station Restoration Project raised $26,000 to purchase an exact acrylic replica of the 4th order Fresnel Lens. This is the lens that created the beacon that shone from the Light Station between 1860-1903. In 2007 a new lens was installed to replace a ship's light that had been illuminating the lantern from dusk to dawn every night. Just as was the case in 1860, the new lens is the single most expensive component of the lighthouse. The 4th order replica beehive lens is approximately 28" tall. The individual prisms that comprise the lens are affixed within a brass frame or divider. The divider and prisms are hinged on one side, allowing access to the interior where a 4th order lamp stood upon a brass base. The lens and lamp are atop a cast iron pedestal, bringing the lens level with the nine panes of glass that create the lantern room configuration.
The Fresnel lens was custom made by Artworks Florida. Fresnel lens replicas are manufactured by importing CAD drawings into computer driven lathes and milling machines. The finished prisms are assembled into the polished brass frame work. Wood shims are used to aim the prisms to achieve the proper light pattern. A glazing compound or lithargeis used for the final mounting of the prisms in the frame work.