Name/Title
Lighthouse LensEntry/Object ID
2022.2.104.08Description
This lighthouse lens, a 3-1/2 order lens weighing approximately 1,400 pounds, remained in the lighthouse until 1972.
The order is based on the focal length of the lens. A first-order lens has the longest focal length, and the sixth is the shortest. Coastal lighthouses generally use first, second, or third-order lenses.
The 100-watt lightbulb used in the prism made it possible for the lighthouse light to be seen as far away as 12 miles. However, the light's wattage was not cost-efficient and was replaced with an LED light.
Fresnel's lens resembles a giant beehive with a complex system of multi-faceted glass prisms mounted in a brass framework. The prisms take rays of light that would typically scatter in all directions and focus them into a single beam, making a Fresnel lens much more efficient than traditional light sources.Location
Building
The Keeper's House MuseumOhio State Park
Marblehead Lighthouse State Park
