With the long, dark winter nights we’re experiencing in the Northern Hemisphere, it is a good time to celebrate the marvel of an invention that brought light to our world centuries ago, and still today.
Even before the first light bulb was invented, a powerful lens was invented.
It was a modern invention of the 1820s that revolutionized the sciences of light and marine navigation.
The lens design, created by a physicist, was maximized to capture light reflection and refraction. It is an array of prisms managing the mechanics of light, extending the light to then-unprecedented lengths.
The inventor, Augustin Fresnel (1788-1827), lived on the rugged west coast of France near Brittany, where tragic shipwrecks repeatedly occurred and human lives frequently perished. He invented the lens for lighthouses, to light up the coast more efficiently for ship captains to see what was in front of them. The first Fresnel lens was installed there, on the coast of France, in 1822.
A Fresnel lens could easily throw its light 20 or more miles.
France, and then Scotland, commissioned the lenses for lighthouses; eventually they spread across the world. The Fresnel lens came to U.S. lighthouses in the 1850s.
Prior to the Fresnel (pronounced fray-NEL) lens invention, oil lamps supplied the light and various inventions helped extend the light, but it was not enough to prevent shipwrecks.
I came upon this discovery not by navigating a ship along the coast, but by hiking on an island in the San Francisco Bay. Angel Island.
In the visitor center, a nearly two-foot glass structure shaped like a beehive was perched on a stand near the door–caught my attention.
I am one of those people who stops in their tracks for shadows and sunbeams, fascinated by reflections and refractions. And this giant piece of glass was winking up a storm at me.
It is 21.3 inches high (.54 m). Fresnel lenses come in different sizes, or orders. Both lenses in this post are 5th Order. 1st Order is the largest, 6th Order is smaller. Link for more info is below.
The original Fresnel lenses can often be seen in lighthouses, like this one at Point Robinson on Vashon Island in Washington. The lamp/lens is inside the lighthouse (below), visible underneath the red, cone-shaped roof.
Here is a closer look at the lens, with majestic Mount Rainier presiding in the background.
Though there are still Fresnel lenses in lighthouses today, the science has largely been replaced by navigational systems like radar and radio signal towers and global positioning systems (GPS).
There are many lighthouses that still have the original Fresnel lenses, most of which are no longer operational. Almost always the lens/lamp is there due to a concerted effort by maritime enthusiasts, volunteers, and donations. Today they are highly regarded and valuable treasures.
The United States Lighthouse Society has a website filled with information about U.S. lighthouses including two lists of lighthouses that have operational and non-operational Fresnel Lenses.
Link: Wikipedia Fresnel Lens
The magic of the Fresnel lens does not stop in the 1800s. Today working Fresnel lenses are found in spotlights, floodlights, railroad and traffic signals, emergency vehicle lights and more.
Photographers use them to illuminate a scene. Athena uses a Fresnel lens flash extender on her camera, especially when we are out birding on night walks or dark days. It is a flimsy plastic lens that attaches to the flash unit and extends the flash up to 300 feet (91 m).
She captured this scene below with her “Better Beamer” flash extender. We were in the Belizean rainforest when a spectacled owl had just snatched up a fer-de-lance snake and landed in a tree 200 feet away (61 m).
The Fresnel lens has been bringing light into this world for ages, whether it was preventing fatal shipwrecks two centuries ago or capturing dynamic owl scenes today. That is something to celebrate.
Written by Jet Eliot.
Photos by Athena Alexander.