I'm guessing 1990's, purple hue coatings, appears same as my 1990's Zeiss Diavari *T phase coating. what I can tell you is, compared to my Swaro Z5, both scope scopes set to same exit pupil size (7mm), that the schmidt scope is brighter (at night with 1/4 moon) & because of larger obj (higher power) has more detail. Have shot many hogs under feeder (bare ground) using moon only, could tell difference between hogs, deer or cows under feeder. if full or bright moon night, could see if buck or doe, of course had to be a decent rack. Heavy #4 will let you "find" crosshairs.