Seeing the light Rare lighthouse lens undergoes maintenance

SEGUIN ISLAND – A historic lighthouse that was commissioned by order of George Washington is having maintenance work performed on a rare lens containing hundreds of prisms that reflect light for miles out to sea.

The work, which began recently, was expected to take about two weeks at the Seguin Island Lighthouse, located on a rocky 64-acre island that guards the mouth of the Kennebec River.

The original Seguin Island Lighthouse was commissioned in 1795, according to the U.S. Coast Guard. The current keeper’s house and light station tower were built in 1857.

The station, which was automated in 1985, uses what is known as a first order Fresnel lens that can reflect light to mariners 20 to 25 miles away. The light has served as a longtime guide in an area that is notoriously foggy with waters that are notoriously choppy; the name “Seguin” is said to be a corruption of an Indian word meaning “place where the sea vomits.”

The lens bears the name of French physicist Augustine Fresnel. His invention in 1822 made his name commonplace along the coasts of Europe and North America.

The work to the Seguin Island lens is long overdue, said Anne Webster, executive director of the Friends of Seguin Island. The work involves replacing broken and cracked prisms and stabilizing others.

The lens is the only first order Fresnel lens in operation in Maine, and it’s the last continuously operational one north of Virginia, Webster said.

The Fresnel lenses are categorized into different classes, or orders, determined by their size. First order lenses, like the one on Seguin Island, are the largest, measuring up to 12 feet tall and 6 feet in diameter, the Coast Guard said.

The Seguin Island lens resembles a giant beehive with a 1,000-watt light bulb in the middle. When the light is on, the light reflects through concentric rings of glass prisms to bend the light into a beam.

In the old days, the lighthouse used an oil lamp to cast the light with a flame.

The island is owned by the Friends of Seguin Island. The Coast Guard maintains the island’s aids to navigation, including the lighthouse.

The Coast Guard is paying for the maintenance work, which is expected to cost about $55,000, said Coast Guard Petty Officer 3rd Class Lauren Downs.