Definition
Because Polaris lies close to the north celestial pole, its true altitude is approximately the observer's latitude. The Nautical Almanac provides three small corrections, a0, a1 and a2, entered with LHA of Aries, latitude and month, which together account for the star's roughly one degree offset from the pole. Their sum, minus 1 degree, is applied to Ho. The method is unavailable south of the equator and degrades in low northern latitudes.
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