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  1. J

    Dodgy vision or Binocular fault?

    Hi, thanks Bill for sharing, so for explanation, step means the difference in height between the two images - this is the smallest tolerance. Divergence means the two tubes are pointing horizontally apart - the tolerance is double that of step and convergence is the tubes are pointing...
  2. J

    Dodgy vision or Binocular fault?

    Hi, the tricky part with seeing collimation problems in binoculars is that the brain is able to merge a certain degree of misalignment... if it's a bit more, you might get a headache over time, but not really see a double image... One can either try to fool the brain by keeping one eye closed...