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    Re: technique for sighting affect accuracy
    From: Bill B
    Date: 2012 May 16, 13:02 -0400

    I have noticed the same thing, though not to the degree you have.  The
    first think to check is eye dominance. In the shooting sports,
    especially pistols, it is advantageous to shoot right handed if right
    eye dominant, and vice versa. I am right-eye dominant, but just barely
    so. Although right-handed, as a kid I instinctively shot my bow and
    arrow and BB gun left eyed until I received instruction.
    I am not clear if this would apply to sextants, and there are very few
    left-handed sextants out there anyway for a lefty with left-eye dominance.
    I shoot the sextant left eyed, if for no other reason than the
    shades/index mirror blocking the sun from the right eye is more
    comfortable for me.
    When I started with sextants the uncorrected vision in my right eye was
    better than that in my left eye, yet my results were consistently better
    (both accuracy and precision) with my left eye. Now my left eye is
    marginally better, and the left eye results are still better.
    As a side bar, I have an astigmatism in my left eye that can best be
    described as turning a lighted sphere into the shape of an egg, fat side
    down, rotated 45d clockwise from upright.  Like wise in my right eye,
    but rotated 135d CW from upright.
    I also have an image that jumps a bit up or down from one eye to the
    other, although my optical system adjusts for this, no eyeglass
    correction needed. It *should* be no problem since I am only using one
    eye to align a sphere to a line, or line-to-line with a horizon IC check.
    I have done exhaustive testing with sun ICs and my left eye IC checks
    are always within tolerance but just a tad over ideal. The opposite is
    true of my right eye. When I rotate the sextant to horizontal, the IC
    checks discrepancies reverse for each eye.  Given the data, we can rule
    out frame rigidity as the culprit.
    The astigmatisms also create a slight difference between sun IC and
    horizon IC checks, nominally 0!2 smaller horizon IC checks with the left
    NOTE: I have never been able to successfully use my eyeglasses with a
    scope or binoculars unless in total darkness--so no help there.
    Past that it remains a mystery to me. Could it be improved balance,
    habit, etc.? I'm stumped.
    Not much help for you, but at least you are not alone.
    Bill B.
    On 5/16/2012 10:35 AM, Randall Morrow wrote:
    > Just some quirky things I noticed lately...
    > I normally shoot with my left eye and when I tried using my right eye
    > accuracy decreased somewhat. Here are some sights and intercepts done on
    > UNSO:
    > Saturn 0.1A left eye, 0.9A right eye
    > Venus 0.2T left, 1.2 T right
    > You can focus a scope to shoot without using your glasses but in my case
    > it decreased accuracy.
    > Arcturus 0.3T with glasses, 3.7 without glasses

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