The Sixth Order Fresnel Lens Seeing The Light

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Application

The Sixth Order lens, the smallest of the regular Fresnel Orders, was used in minor lights, showing the line of branch or secondary channels or the ends of piers, breakwaters and jetties. One of these lenses was used in the Cheboygan Front Range Light.

Specifications:
Lens height: 17.05"
Focal length:  5.9"
Weight of assembly:  220 lbs
Relative brightness (over sixth order): 1x
Useful range:  Up to 5 nautical miles
Number in US lighthouses in 1884: 123
Number in US lighthouses in 1922:  65
Oil consumption per hour: 3.14 oz.

References

Annual Report of the Lighthouse Board, 1884
The United States Lighthouse Service
, Dept of Commerce, 1915
Aids to Navigation Manual, US Coast Guard, 1945
Comparative Table of Lens Orders, Mabel A. Baiges, 1988
Letter from Helen & Al Gademsky, 07/02/01

Terry Pepper. This page updated 12/02/2007

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