Where can I find a third order fresnel lens that would usually be found in a lighthouse?

Question

I'm looking for a fresnel lens something like the once seen here, http://en.wikipedia.org/wiki/Image:MuseeMarine-phareFresnel-p1000466.jpg

I am looking for size "Third Order Large."

Thank you,
Max E.

Answer 1

They're made to order and by design, unless you luck out and find a suitable used one on eBay or for sale by a municipality or other government or maritime agency. I'd probably make my own from scratch.