Fresnel Lens ExhibitPonce de Leon Inlet Lighthouse - Florida
The Ayres Davies Lens Exhibit Building at the Ponce Inlet Lighthouse houses an amazing array of Fresnel Lens. The exhibit contains the fixed first order Fresnel lens that was originally installed at the Ponce de Leon Inlet Lighthouse in 1887. It also has the beautiful rotating first order Fresnel lens from the Cape Canaveral Lighthouse. There are also a rare third order Fresnel lens and and a fourth order Fresnel Lens.
The delicately hand-crafted Fresnel Lens was a rather expensive item in the budget for Lighthouses built in the 1850's. A First-Order lens cost from $5,000 to $10,000 (over $300,000 in today's dollars). The cost depended on the number and delicacy of the prisms used to build the lens as well as whether it was rotating or not.
There were 6 sizes of Fresnel Lens that were used depending on function of the lighthouse and how far the light need to be seen. The largest was the First Order lens which had a height of 8 feet 6 inchs and a diameter of the base of 6 feet. The weight of the assembled lens was about 12,800 pounds. These could be seen up to 22 miles at sea on a major tower.
The smallest was the Sixth-Order Fresnel lens with a height of 1 foot 5 inches and a diameter of a little under 1 foot. These would be used to mark channels.
A little lighthouse history since this is an off week and #NotaLighthouseThursday
with +Heiko Köster #fresnel #lenses #lighthouse #Lighthousephotography #history