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    Re: Impossible lunar example
    From: Antoine Couëtte
    Date: 2010 Aug 29, 10:00 -0700

    Thank you Frank for publishing Maskelyne's Comments about our now well known "impossible Lunar".

    Let us use Maskelyne confession then :


    Also Ex. IV p. 31 and 36, is in the same Situation, owing to a Mistake in transcribing the Moon's Altitude 71d 6'2" instead of 41d 6'2"


    So we can now rework our Lunar example with :

    20 NOV 1796 TT-UT=14s4

    at one same unknown (and still yet to be determined) time - expected to be in the vicinity of UT=18h46m - we observe the following three SEXTANT data (all assumed to have been observed at the very same instant) :

    SUN-MOON SEXTANT DISTANCE 102°57'5, SEXTANT Height of SUNLL=18°47' and SEXTANT Height of MOON LL=40°32'

    Height of Eye : 20 ft with all other conditions assumed to be standard.

    We can compute the following 2 positions :

    UT of Sextant Observation #1 = 18h23m49s1 with position #1 at N3658.6W14427.7,


    UT of Sextant Observation #2 = 18h23m35s0 with position #2 at S2515.5W17713.4

    I did not crosscheck the results published hereabove against Frank's Computer results, but they should agree to better that 0.1' as (almost) always.

    ... Well... , both of these positions fall in the middle of nowhere in the Pacific Ocean .. . with none of them anywhere near the Greewhich W007° meridian ... which we already knew thanks to George's clever insight.

    So we might think that Maskelyn's data correction possibly either as incomplete - since the UT value is close from the one he has quoted -, or as a plausible reason that his initial example was created "ex nihilo" since, even corrected with his amended height, this Lunar could NOT have happened be anywhere near the Meridien W009° ...

    Unless somebody has a reasonable explanation to the above, including any and all errors of mine, this "most important question" of ours still remains an open one ...

    Thank you for your Attention and

    Best Regards


    Antoine M. "Kermit" Couëtte

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