Monday, June 17, 2013

For more information about lighthouses and lenses goto:

Wednesday, December 19, 2012

The Lens at Hyskeir Island

     The lens at Hyskeir, Scotland was built by the Chance Brothers Company in England.  It had three bull's-eye panels covering 60 degrees each.  These panels are another example of the use of the Spherical Panel design.  Behind the Bull's-eye panels was a 180 degree totally reflecting prism panel, which intensified the light to the bull's-eye panels. The lens was installed in 1904.  The lens is currently operational in the tower.  

The Hyskeir Lens from the Front (c) Patrick Tubby

The Hyskeir Lens from the Rear (c) Patrick Tubby

Friday, May 20, 2011

The Lens at Round Island, England

      The lens at Round Island, England was built by the Chance Brothers Company in England in 1888.  It was a two level bi-form lens where each level had six bull's-eye panels covering 60 degrees each.  This lens displayed a flashing red light.  The lens was removed in 1966 and its location is unknown.
Drawing of the Lens at Round Island by Chance Brothers

Photo of the Round Island Lens by Chance Brothers

Friday, February 11, 2011

The Lens at Bazaruto Island, Mozambique

    The lens at Bazaruto Island, Mozambique was built by the Barbier & Benard Company in France in 1913.  It was a  flashing lens with three panels each covering 60 degrees and a 180 degree totally reflecting prism panel in the rear.  It was installed at Bazaruto Island in 1913 where it remains in the tower mostly destroyed and replaced by a small rotating lens mounted inside.

Photo of the Bazaruto Island Lens (c) Sam Seyffert and used with permission

The Lens at Fair Isle North, Scotland

    The lens at Fair Isle North, Scotland was built by the F. Barbier Company in France in 1892.  It was a four sided double flashing lens having four panels each covering 90 degrees and using the Spherical Prism Design for the central portion and the Equiangular Prism Design for the edges.  It was installed at Fair Isle North in 1892 and was later removed from Fair Isle North on April 23, 1980 and its current status is unknown and possibly destroyed.

Drawing of the Lens at Fair Isle North by F. Barbier

Photo of the Fair Isle North Lens by F. Barbier

Tuesday, March 9, 2010

Wrapping it Up

    We have discussed why Hyper-radial Lenses were made and who made them.  We have also discussed where these lenses were and where they still remain today.  I have given you the location of all the sites where a lens can still be seen, and drawings and/or photos of every lens that I have been able to obtain.
    This ends the story for now.  People all over the world are still searching for additional data about these lenses and it appears that every six months or so some new information is found - a new drawing, photo, or complete lens location.  Should additional data become available I will add it to the story.  If anyone reading this knows of an additional Hyper-radial lens out there somewhere please let me know at:
    On April 16, 2010, I received updated information on the location of the lens panel used in the 1885 South Foreland Trials and on the maker and current location of the Sule Skerry Lens for which I want to thank Dr. A. Morrison-Low of the National Museums of Scotland.  Several posts have been updated as a result.
    On May 14, 2010, I received a report from James Skinner at Trinity House stating that the upper lens from the Bishop Rock Lighthouse is on display at the National Maritime Museum in Falmouth UK from February 2010 through December 2011.  Thank you Mr. Skinner.
    Thank you for your interest in this project.  - Thomas Tag

The Lens at the Bell Rock, Scotland

    The Lens at the Bell Rock, Scotland was built by the Henry-Lepaute Company in France in 1901.  This is the only known Hyper-radial Lens to have been built by Henry-Lepaute.  It was the largest Fresnel lens to be placed in the Bell Rock Lighthouse tower where it was installed in 1902.  The lens was a composite of a Hyper-radial and a first order.  It had a Hyper-radial panel using the equiangular prism design and two partial first order panels covering 180 degrees and formed into one half of a bi-valve lens configuration.  This side of the lens used both interior and exterior red panels to produce a red flash.  The opposite side of the lens consisted of two first-order 90 degree totally-reflecting prism panels to further increase the light to the red side of the lens.  In the center of the totally reflecting prism panels was a single Hyper-radial flash panel of the spherical design that projected a white light, in the opposite direction from the red side, and at each edge of this side of the lens were small vertical prism lenses that also projected white light in this direction.  Thus one side of the lens produced a very strong red flashing light and the opposite side of the lens produced a white flashing light of equal power.
    This lens was removed from the tower in 1964.  One half of one of the Hyper-radial panels can be seen at the Signal Tower Museum in Arbroath, Scotland.  The location of the remainder of the lens is unknown.
Drawing of the Composite Red and White Lens at Bell Rock by Henry-Lepaute