What does a
first-order Fresnel lens look like? While posting information to my blog about the lighthouses, I usually mentioned a particular lighthouse was equipped with a specific size lens. Over the past few months, I've had inquiries from different people wanting to know what's the difference in the size of lens'. Starting with today's post, I will attempt to show the different size lens'. It may help you to understand sizes better if you keep in mind, the larger the number in the name of the lens, the smaller the lens. For example, a first-order is larger than a third-order.
The following two lens' are examples of
a first-order Fresnel lens. I have personally seen both of these lens'.
The first-order Fresnel lens, pictured below, is located in the lantern room of the Umpqua River Lighthouse, Winchester Bay, OR. This lens was manufactured in 1890 by Barbier and Cie of Paris, France. The lens has twenty-four bulls-eye panels. Every two minutes the lens completes a revolution. Its signature light is two white flashes followed by a red flash. The lens has 616 prisms and weighs two tons. It is nine-feet seven-inches tall and six-feet two-inches wide.The original lamps which provided the light were replaced by electricity in the 1930's. The light is currently powered by a 1,000 watt quartz bulb, visible in the photo below. The light can be seen for 19 miles out to sea on a clear night. This lens is only one of two first-order lens' that you can climb up inside to see the massive lens close up. As of the time of this posting, this lens operated twenty-four hours a day, seven days a week. It is operated and maintained by Douglas County. This light was reclassified in 2011 by the U.S. Coast Guard from a Primary to a Secondary aid to navigation. The Umpqua River Lighthouse is listed on the National Register of Historic Places as well as the nearby former USCG Station Umpqua River. The former USCG Station now houses the Umpqua River Lighthouse Museum. Both the museum and the lighthouse are open for daily tours, seasonally. I took this picture during the time I volunteered as a tour guide in the summers of 2004 and 2005. You can also read about this lens in my book "The Wickie," a heart warming story about the lighthouse keepers and their challenges in the two Umpqua River Lighthouses.
This first-order lens is housed in the Westport Maritime Museum, Westport, WA. The lens was manufactured in France in 1888. This lens is from the Destruction Island Lighthouse and it was turned by a clockwork mechanism. The lens has twenty-four "bulls-eye" panels which cast a flashing light to a distance of over 26 miles. Originally, the lamp was lit by oil and had up to five hollow wicks. Whale oil was preferred until it became too expensive. Lard was used in the 1860's and then replaced by kerosene in the 1880's. In 1968 the Destruction Island Lighthouse was automated.. The Fresnel lens was dismantled in 1995, removed from the lighthouse and placed in temporary storage in Astoria, OR. In 1998 the display building was built at the Maritime Museum in Westport, WA. This location was selected because it was the closest place where the lens could be appropriately cared for and made accessible to the public. It took a team of 5-6 people who worked for a week to assemble, clean, and polish the Fresnel lens at Westport. At the time of my visit here in 1999, six lighthouses in Washington state still had operating Fresnel lens lit by an electric bulb. I purchased this picture via a post card from the Maritime Museum. Photo by Tammy Diamond.
