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Hi Morton,
I'm fairly sure Stellavue, Orion and others were assembling scopes using ED doublets in the 80-130mm range from a chinese factory mass-producing these, possibly Kunming Optical. The only question IMHO was whether all received lenses at random, or whether some (e.g. StellaVue) were paying more to cherrypick the best ones off the production line.
In any case its a pity you didn't ask when I was selling my Orion ED105 f/7 last year, optically it was as good as one could expect for an ED at that focal ratio. At high power it gave a nice Airy disk with a hint of colour inside/outside focus. Field curvature did exist - not bothersome visually, but for imaging you could nail that with a flattener, a few to choose from. You'd have to go to a triplet or alternatively an ED doublet at about f/10 to do significantly better at the same aperture.
Last edited by Wavytone; 03-01-2016 at 10:01 PM.
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