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  1. H

    Harpia Extender

    I'm not sure why we can't seem to connect about this. Maybe somebody else can join in. Does it help to say that on the USAF 1951 size and distance are interchangeable? There's no difference between changing from one set of line pairs to the next 12% smaller size and just moving the larger set...
  2. H

    Harpia Extender

    Nothing much would be gained at any distance from boosting the size of the smallest resolved details beyond 70x for someone like me with eyesight acuity of 20/15, which is about average. I could already see 12% smaller line pairs at 70x through the 92mm reference scope set up next to the Harpia.
  3. H

    Harpia Extender

    Yes, there would be some practical benefit to boosting the size of the smallest resolved details for those with below average acuity, but that will come at the price of degraded brightness and sharpness at lower magnifications, a disadvantage unique to the Harpia design.
  4. H

    Harpia Extender

    Hi Lee, I'm not sure I'm following you here. A conventional telescope's "native resolution" doesn't really change with magnification or distance, but the Harpia design doesn't have a single "native resolution". We know without even measuring that its resolution is increasingly limited from...
  5. H

    Harpia Extender

    Hi Binastro, Keep in mind that I'm choosing to limit my resolution target to high contrast line pairs viewed under daylight conditions so that I can make repeatable comparisons. I think that's much easier for the eye to resolve than low contrast astronomical targets, which is why empty...
  6. H

    Harpia Extender

    We'll need properly done measurements to know exactly what the resolving power of even one sample of the Harpia is. However, using the USAF 1951 chart I was clearly able to see that the unit I tested could not resolve line pairs as well at 70x as a diffraction limited scope of slightly less...
  7. H

    Harpia Extender

    Hi Bsimmins, Increasing the magnification across the zoom range of the Harpia, whether with an extender or a shorter FL eyepiece, might not be such a good idea. Even at 70x, where the optical performance is optimal, the one I tested was at its visible resolution limit for most people's eyesight...
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