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    Re: Two Mercury Lunars
    From: Antoine Couëtte
    Date: 2025 Dec 29, 04:24 -0800

    Dear Modris,

    Thanks for your detailed analysis.

    After checking that my Ephemeris is adequately accurate - only 0.01' difference in our Cleared distances on both days - , we are left with differences of 0.08' in our respective topocentric near-limb apparent distances. First time I am so far from Paul's Lunar 4.0. . Most often if not "always" I am off by up to 3" to 4" essentially attributable to my "non perfect" Moon Ephemeris.

    But you very kindly published the sought explanation for these unexpected 0.8' repeated differences.

    I am performing phase correction too, but I am not using Bernoulli's 18th Century refraction. Accordingly any difference can be attributed to essentially different refractions, only appreciable at very low altitudes.

    Let's have a closer look then.

    -15.12.2025.: 13,81' . I am computing 13.76' : a 0.05' difference (my sextant observed distance is smaller than Paul's) which would account for a significant part of this 0.08' difference defined hereabove

    -16.12.2025.: 14,17' . I am computing 14.09' : a 0.08' difference (same configuration on sextant distances) having the very same outcome.

    This is again telling me that both Paul and I are likely using extremely similar algorithms to solve Lunars onto the same perfectly circular Moon. It is also showing the importance of working with a sufficient number of digits in any meaningful comparison process, even if such extra digits have absolutely no physical significance whatsoever.

    So - thanks to you Modris - I can rest in Peace now.

    Kermit

       
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