ADDITIONAL INFO SATURDAY PM BELOW: Made by the famed Perkin-Elmer Company at its Bodenseewerk in Germany, this catadioptric lens was originally in a "cine-theodolite" model Kth-57, for tracking and filming the launch of missiles and rockets in the fifties and sixties. It appears in very fine condition, with no visible damage. It produces a 6 centimeter image circle, presumably for a large format movie camera. For current telescopic or photographic purposes, it may be necessary to reduce the size of the image. I do not have the expertise to figure this out, and I don't want to sell or give this lens to someone who doesn't have at least a chance of getting it set up. The outward facing side of the secondary mirror structure is mirrored. The lens can be stopped down from an aperture of f/6.3 to more than f18 by turning the full-width, knurled ring in its center, which opens and closes an internal iris like manual SLR lenses in the good old days, only bigger. (The result is that, when fully stopped down, only the central column of light behind the secondary mirror is left open, which may suggest that the secondary is to some degree transparent to light from its outer side in spite of the mirrored surface?) It is marked as a 100 centimeter objective, which I believe is its focal length. It has a custom made wooden case in the military style. The outer body of the lens is 10" diameter and the corrective/front-end glass is 8" in diameter. I do not know what precise type of catadioptric this is. I do not want to throw this gorgeous lens away, so I am putting it up for Auction here with a reserve and opening price of only $100, hoping it will find a good home. The greater cost would be shipping, if you do not pick it up in person. The lens weighs about 28 pounds, and the box about 32 (60 total). I don't want to ship this at all, it would just be too big a job to prepare it and too expensive. The box is 18.5"W x 14.5"D x 24" high. This will be a seven day auction to the highest bidder who will pick it up in person. I can email larger photos on request.
Saturday addition: This afternoon I set the lens up aimed out a window and hand-held an eyepiece to get an idea of the distance from the back of the lens to the focal plane. For objects a few hundreds yards away it was about 4" from the back of the lens to the first element of the eyepiece, growing to 6 inches or so for objects a few dozen feet away. I believe I also saw reticle circles in the light path, and that some cleaning of inner optical surfaces would be a benefit.