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    Re: Custom Polaris Table SHA / Dec 2020-2030
    From: Frank Reed
    Date: 2019 Oct 22, 09:13 -0700

    Greg, you wrote:
    "You are correct that a tenth of a minute precision in Polaris SHA is not necessary."

    This is a recurring problem with Polaris tables. Even the tables in the almanacs typically quote the SHA of Polaris to the nearest minute of arc. This is simply nuts. A degree is good enough, as Geoffrey has said, and if you want a little more (as a safety digit) then give the SHA of Polaris to the nearest tenth of a degree (at 89.6° Declination, 0.1° in SHA is better than a tenth of a minute in SHA at the equator).

    And:
    "A tenth of a minute precision in declination is justified I would think."

    As much as it is anywhere else in celestial navigation, yes (which is to say, it's generally over-kill, but we can count it as a safety digit to reduce round-off error).

    Frank Reed

       
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