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    Re: Using sun compass for calibrating boat compass
    From: Sean C
    Date: 2014 May 8, 04:38 -0700

    "If declination, LHA and latitude remain constant can your theoretical
    body have two Hc's? One of the 3 variables would have to change for that
    to happen, and it becomes a whole different scenario." -Bill B.

    Oh, sure. I was just trying to point out that the azimuth, when calculated this way, is indeed tied to the Hc. However, even if the difference between Ha and Hc were considered, it seems that the effect of refraction would be all but cancelled out because as the sensitivity to a different altitude increases toward 90°, the effect of refraction decreases.

    I did in fact try changing the LHA and latitude by one degree and the azimuth only changed by a degree or so. But, as you have pointed out, all of this is moot since refraction really only works in the vertical and even then it's a tiny difference. And, as mentioned, you can use a different method entirely to calculate the azimuth, independent of Hc.

    Regards,
    Sean C.
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