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    Index Error - Real vs. Artificial Horizon
    From: Paul Fithian
    Date: 2013 Feb 28, 13:24 -0800

    While playing around with the sextant, I've noticed a big difference in index error when viewing things far away vs. near.

    For example, if I adjust the horizon mirror so that a near (5' away) horizontal line matches up through the glass and the mirror images, these images don't line up when I view a horizontal line that is several hundred feet away.

    Which one do I choose to apply the right index correction for the artificial horizon readings? I know I have to take the Hs, apply index correction, then take 1/2 of this reading to get Ho.
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