The Fresnel Lens

History

On September 7, 1873, the lighthouse supply ship “Haze” delivered a new lens to the Pointe aux Barques Lighthouse.  The lens was a sixteen panel Fresnel lens, named after French physicist Augustin-Jean Fresnel.  The 16 panels were assembled at the top of the 89 foot tower, the lamp was lit, and the lens went into service rotated by a weight system similar to that used in a Grandfather Clock.

The Pointe aux Barques Fresnel lens is a 3rd order lens, with 1st order being the largest and 6th order being the smallest. The lens is almost 43 inches in diameter, 5½ feet high, and weighs approximately 1,400 pounds.  The nearby diagram illustrates how the Pointe aux Barques Fresnel lens operates.  The upper and lower sections of each panel are called catadioptrics – they use both reflection and refraction to direct the light from the oil lamp into horizontal rays.  The dioptrics – lenses – are located above and below the “Bull’s eye” and accomplish the same purpose using only refraction.  The “bull’s eye” is a simple lens that focuses light out to the horizon. 





 
The Henry - Lepaute Company of Paris manufactured nine Fresnel lenses for Great Lakes lighthouses.  Five of the lenses were stationary; four were rotating.  The four that rotated had four, eight, twelve and sixteen panels, respectively. The Pointe aux Barques lens is the only sixteen panel, 3rd order lens ever installed on the Great Lakes.
 
The new Fresnel lens, like the simpler lens that had been used before it, continually warned mariners of the dangerous rock ledge stretching two miles into Lake Huron from Pointe aux Barques.  The lens was in service for almost 100 years, finally being removed from the tower in 1969 and replaced by an electric beacon.  Upon decommissioning, it was not feasible to display this artifact at Point aux Barques because no museum or other suitable facility then existed.  Thus, the lens was originally stored in a Coast Guard warehouse in Detroit.  In 1970, the lens was moved to Harbor Beach and displayed in the City’s office.  Soon thereafter it was moved to the Grice Museum in Harbor Beach where it could be more readily seen by the public.  In 1987, the Lens was moved to Huron City Museums, midway between Port Hope and Port Austin, where it could be viewed as part of a tour of the museums. 
 
Coming Home
 
By 2008, the Pointe aux Barques Lighthouse Society, which had been formed in 2002, had matured as an organization had turned the Lighthouse Museum into a first class facility.  Accordingly, the Society began to look into the possibility of the Lighthouse’s Fresnel lens being returned to Pointe aux Barques.   
 
In June of 2008, the Society contacted Arlyn Danielson, the Coast Guard Curator, and requested any assistance she might offer in having the lens returned to Point aux Barques and put on display in our museum.  Ms. Danielson was extremely helpful and soon furnished the Society with the Coast Guard’s specifications for maintenance and display of  Coast Guard artifacts (e.g., climate control, security system, etc.).  The Society determined it could meet these requirements and decided to pursue the matter further. 
 
In initial conversations, Ms. Danielson indicated that the Coast Guard records, which dated to the 1970s, showed that the Pointe aux Barques lens was in Harbor Beach.  The Society assured her that such was not the case and, together with the Coast Guard, began to investigate (1) why, when and how the lens was moved to Huron City, and (2) whether there was any documentation indicating that the Coast Guard had authorized or acquiesced in the lens being in Huron City. 
 
The Society’s and the Coast Guard’s efforts ultimately uncovered no evidence that the Coast Guard had authorized the transfer of the Fresnel lens to Huron City.  Accordingly, Curator Danielson contacted the Huron City Museums, which in turn questioned whether there was any evidence of ownership by the US Government.  After additional research, and a couple of false starts, the Society was able to provide the Coast Guard with documentation that the lens was the property of the United States.  Subsequently, the United States filed suit in federal District Court in Bay City against the organization that operates the Huron City Museums. 
 
After a trial date was set, the parties settled and the Coast Guard arranged to take possession of the lens and loan it to the Society for display at the Pointe aux Barques Lighthouse Museum.  On June 1, 2013 the lens was removed from Huron City and moved to Coast Guard Station Harbor Beach.  In early August, lampist Kurt Fosburg began restoration and cleaning of the lens and, on Thursday, August 23rd, the lens was returned to its original home at the Lighthouse.  Harbor Beach resident Scot Richardson and Society member Larry Becker assisted Mr. Fosburg with moving and reassembly of the lens.  The Michigan State Historical Preservation Office (SHPO) provided the majority of the funds for the restoration through a grant made possible by the State of Michigan Lighthouse License plate program. The Society provided the remaining monies necessary to finish the job.  The following is a photograph of the lens in its new home:


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The lens is now on display in a secure environment where it can be viewed by the public seven days a week, late-May through mid-October.  The Lighthouse and Museum are located six miles north of Port Hope just off M-25.  There is no charge for admission, but donations are accepted. Additional information can be obtained by calling (989) 428-3035.