Hello Fred, I wonder if I still have the bill of the mirror. I have actually ordered it from LUMICON, who had a businees near San Fransisco where I was living at the time, and he got it from Parks. So, if I still had the bill, it would be from LUMICON, and it would be for all the items I sell. The finder has the inscription of Parks on it. I checked the mirror using a method proposed in Sky&Telescope. The focal length proved to be slightly bigger than F/6, namely instead of being 1908 mm it was 1914 mm, if I remember well. This had been taken into account when I planned the tube. The telescope has been once assembled on a wooden tube 2.00 m long. The mount ( a fork that I had planned based on old German blueprints from KOSMOS VERLAG, Muenich) was never built : My wife, when she saw the huge tube, simply said "Either this thing or me". Using the tube without the mount, supported on a table, I made some observations of terrestrial targets. They looked very good and luminous. The tube has been dismantled and thrown away a few days after it was built. The mirror etc were dismantled and stashed in cartons. I purchased a C8 after that, to replace the old 60 mm Unitron refractor that I had. My e-mail is ilvaf@the.forthnet.gr. You can write to me whenever you like. I hope my english is good enough. Regards, ILIAS.