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    Re: D-value: its step and its sign
    From: Andrew Bauer
    Date: 2022 Dec 11, 10:51 -0800

    Please ignore the following sentence in my initial post:

    "If I was to print the sign in the above data starting from 00h on 16th January 2023, I assume it would appear as follows: -13.6 -13.5 +13.4 -13.5 +13.3 -13.4 +13.2 -13.3  13.1  13.1 -13.1 +12.9 .......
    which looks utterly confusing to me."

    I realized immediately after that the sign applied to the d-value in a Moon Reduction calculation applies to whether the Moon's Declination is increasing or decreasing (not the d-value)!

    But this can also be misconstrued mathematically ... am I correct in thinking that increasing or decreasing applies to the POSITIVE d-value that's printed in the HMNAO almanacs?
    In other words the sign always changes when the Moon passes the Equator (Declination = 0.0)?
    (I am referring to the sign spoken of in David Burch's Celestial Navigation 2nd edition, Chapter 9 "Moon Sights", penultimate paragraph on page 100.)

    Thanks for looking at this,
    Andrew

       
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