Fresnel Lens

Sankaty Head Light was built in 1849 on the Siasconset bluff and became the first Massachusetts lighthouse with a Fresnel lens, and the first lighthouse in the United States with a Fresnel lens as part of its original equipment.

Outfitted with this second-order Fresnel lens purchased in Paris with Congressional appropriations of $6,000 in 1848 and $2,000 in 1850, it’s brilliant light was visible up to 24 miles away, and was referred to by fisherman as “the blazing star.” The lighthouse was electrified in 1933. In 1950, the original Fresnel lens was removed and replaced with two aerobeacons. The lens was transferred to the NHA for permanent display in the Whaling Museum. In the newly renovated Whaling Museum completed in 2005, it now greets visitors in the Whaling Museum lobby, where heavy weights connected to a clockwork mechanism still slowly turn the beacon.

Frenchman Augustin Jean Fresnel (1788–1827) created lenses using a central piece of glass called a bull’s eye surrounded by concentric rings of glass projecting beyond one another. This design allowed five times more light to be transmitted than with a traditional convex lens.


Banner image by Emily Elisabeth Photography

The Nantucket Historical Association preserves and interprets the history of Nantucket through its programs, collections, and properties, in order to promote the island’s significance and foster an appreciation of it among all audiences.

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