Fresnel Lens
This is the inside of the Fresnel Lens of the Tybee Island Lighthouse, near Savannah.
I estimate that the two light bulbs are about 4X12 inches, and the Fresnel is about six feet in diameter. The optics of the Fresnel make the light visable for over 20 miles. Impressive!
Bob
I estimate that the two light bulbs are about 4X12 inches, and the Fresnel is about six feet in diameter. The optics of the Fresnel make the light visable for over 20 miles. Impressive!
Bob
posted by Bob Dein at
9:15 AM
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