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Message: <blockquote data-quote="OPTIC_NUT" data-source="post: 3367963" data-attributes="member: 121951">(said tongue in cheek, of course)The kind of standard is a tip-off that the discussionwon't be practical or rational.  The Nagler is mostly a stack of meniscus lenses thatcheat the reaper and sneak around the of thin-section-spherical limits, but their nose is inspiredby Erfles and by Konigs.  I've sold on most of the 11-13 degree binocularssince finding the Toei-Kogaku-10degs, but there were somesurprising designs.  In terms of proving things, the target I want to attain mostis decent measurements of the quieter 'amber' coatings fromJapan, 1950-1980.  A decent and large enough spectrophotometeris 40K-$100K, and photo meters are only +/- 2%.If I can measure the aggregate loss, entered mid-band and witha method of removing hysteresis, improving accuracy, that wouldbe satisfying.  The little asphere in my pocket defends me from someimperious assertions..that's a lot cheaper and more obvious!Or...some means of measurement might drop in from some odd specialty.Surplus? Meanwhile, the restorations accumulate, waiting to testify..to a world we do not know well...</blockquote>