The St. Augustine Lighthouse, built from 1871-1874, received a first order Fresnel lens from Parisian lens maker Sautter, Lemonnier & Cie. The lens has 370 individual prisms and weighs roughly 2 tons. A 1000-watt light bulb currently serves as it light source, as it has since the tower was electrified in 1936. The lens built for our lighthouse has three “bulls-eye” panels that send out beams of light. When the lens rotates, the rotating beams create the illusion of flashes to observers, a unique timing characteristic that differentiates our lighthouse from others and makes it identifiable at night. When first installed in 1874, a clockwork mechanism rotated the lens once every nine minutes, displaying a flash every three minutes. Today, with an electric motor, these flashes appear every 30 seconds. 📸: jwilson_aerial_photography #staugustinelighthouse #lens #fresnellens #light #staugustine