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    Distance off, by sextant angle
    From: Tony Oz
    Date: 2019 Jul 17, 06:00 -0700

    Hello!

    Some time ago I "invented" a way to estimate a distance to a ship by using the HoE correction table alone. It was an error. Robert VanderPol II was kind to provide the dedicated HO-9 Table 39. I'm very uncomfortable with feet|yards|inches, so I decided to reverse-engineer that table.

    In metric units the formula behind that method is:

    • dist[m] = HoE[m]·ctg(dip+α) = HoE[m] / tg(dip+α)

    where α is the angle between the waterline of the object and the horizon behind the object; the dip is the familiar HoE correction angle taken arithmetically (without the sign).

    May be it is a bicycle invention but I did not meet this formula in the wild.

    Hope it helps (me).

    Warm regards,
    Tony

    60°N 30°E

       
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