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    Altitude correction using Artificial Horizon?
    From: Kirk Benson
    Date: 2000 Sep 05, 6:01 PM

    Is it necessary to apply any correction for altitude when reducing a sun
    sight taken with an artificial horizon?
    If the two sextant images are superimposed, I could presume that the sight
    is the center of the disc and no correction is necessary.  However, the
    correction tables in the Nautical Almanac show that the correction is
    skewed between UL and LL.  For example, at an apparent altitude of 20
    degrees in September, the corrections are +13.5(ll)/-18.3(UL).  The total
    difference is 31.8' which is exactly twice the SD of 15.9'.  So I might
    argue that I should use a correction "in the middle" of -2.4'.
    Any clarification on this point would be appreciated.
    Similarly, if I take the sight by aligning the LL of the sun image with the
    UL of the image in the AH, should I just correct the sight by the SD?
    Kirk Benson
    34d 10.8' N
    84d 12.7' W

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