Lighthouse Lens and Lamp Research at the
Long Island Chapter of the United States Lighthouse Society
PO Box 21, Greenport, NY 11944
631-477-4121/631-645-5230
Fax: 631-477-0198 E-Mail: LILighthouses@aol.com

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Photo courtesy of Jean Ruland.

This rare and unusual photograph shows the interior of the Shinnecock Bay lighthouse's Fresnel lens as it appeared in 1918. In the photo, you can see the incandescent oil vapor lamp, the reflector behind it, and the first order lens within which the lamp and reflector resided.

The light's characteristic was a Group Flashing White every 7.5 seconds. More specifically, the mariner would see the following repeating sequence:

.3 second white flash
1.6 second eclipse
.3 second flash
1.6 second eclipse
.3 second flash
3.4 second eclipse

This lens and lamp combination replaced the fixed white light that had been installed when the tower was built in 1857.


To see an Incandescent Oil Vapor (IOV) Lamp, visit Page 12.

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Copyright © 2001 Long Island Chapter, USLHS