Dirk, are you sure it is assembled correctly and that your cross-section is correct? I ask because lenses with an, not to mention both, outer elements concave outwards are really quite uncommon.

Does it form an image? If so, what is its focal length, more-or-less? I ask because I have some USAF data sheets that might shed light. They're ordered by focal length, so I'd like to know roughly where to dive into them.

There's nothing like it in 1963 GOI catalog's generic cross-sections at the front; if you don't know this catalog, you can download a copy from http://www.lallement.com/pictures/index.htm, look in "files."

There's also nothing like it in Eric Beltrando's catalog (www.dioptrique.info, if you don't know it), but he's interested mainly in older designs.

The holes make no sense at all.