Search results
Results from the WOW.Com Content Network
A Fresnel lens ( / ˈfreɪnɛl, - nəl / FRAY-nel, -nəl; / ˈfrɛnɛl, - əl / FREN-el, -əl; or / freɪˈnɛl / fray-NEL[ 1]) is a type of composite compact lens which reduces the amount of material required compared to a conventional lens by dividing the lens into a set of concentric annular sections.
A zone plate is a device used to focus light or other things exhibiting wave character. [ 1] Unlike lenses or curved mirrors, zone plates use diffraction instead of refraction or reflection. Based on analysis by French physicist Augustin-Jean Fresnel, they are sometimes called Fresnel zone plates in his honor.
The new all-white lighthouse tower was completed in 1868, receiving a first-order Fresnel lens made by Henry-Lepaute and Company of Paris, France that was first lit on May 10, 1868. [ 1 ] [ 6 ] The lower three levels of the tower served as the living quarters for the keepers and his assistants complete with kitchen, living room and bedrooms.
Point Conception Light. / 34.4487528°N 120.4707528°W / 34.4487528; -120.4707528. continuous blast every 30s. Fl W 30s. Point Conception Light is a lighthouse in Santa Barbara County, California, on Point Conception at the west entrance of the Santa Barbara Channel, California. [4] [5] [6] One of the earliest California lighthouses, it ...
The lighthouse was built in 1905, to a conical design using granite blocks on a granite foundation, and equipped with one of the few first-order Fresnel lens used. The lens assembly stands about 12 ft (4m) tall and is now at the Smithsonian Institution. The light was the setting for the climactic storm in the 1948 film Portrait of Jennie.
August 5, 1998. Cape Hatteras Light is a lighthouse located on Hatteras Island in the Outer Banks in the town of Buxton, North Carolina and is part of the Cape Hatteras National Seashore. [ 2][ 3][ 4] It is the tallest lighthouse in the U.S. from base to tip at 210 feet. The lighthouse's semi-unique pattern makes it easy to recognize and famous.
Little is known of the first front range light. In 1879 a new front range beacon was erected 448 feet (137 m) southeast of the light tower. This light, known as the Pensacola Bar Beacon, was a square pyramidal wooden tower, 26 feet (7.9 m) tall, sitting on a point 29 feet (8.8 m) above sea level, so that the light was 55 feet (17 m) above the ...
On May 15, 1874, the Gay Head Light was changed from flashing white to "three whites and one red" to differentiate the light from the area's two other principal lights located at Sankaty Head and Montauk Point. All three lights had Fresnel lenses, however, the Gay Head Light was the only light of the 1st Order.