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    Re: Lunarian Puzzle
    From: Antoine Couëtte
    Date: 2024 Apr 14, 11:06 -0700

    Jim,

    In reply to your comments about Stellarium actual fitness to CelNav needs, I resorted to what I should have done from the very onset: reviewing my "Marine Navigation Vol 2" copy (2nd Edition, 1981, Naval Institute Press)

    And until I forget one more time about it, I learnt (again) from this CelNav Course that the "Apparent Altitude" , aka "ha" pertains to the sextant altitude corrected for instrumental error, dip and semi-diameter.

    In other words, here the Sun "Apparent" Altitude (ha) at +37°13'51.6" pertains to the topocentric refracted Sun Center with Height of Eye = 0 ft.

    For Apr 08th, 2024 and starting from 47°36'24"N 057°36'49"W as the Eclipse Island position, and for UT = 18h35m08s the on-line Lunar calculator indicates Error in Lunar 0.00' , with a Cleared distance at 23.3', exactly matching your initial Lunar Puzzle submission.

    So far, so good.

    But ...

    ... what actually remains a "puzzle" to me is that for the very same environment - i.e. the very beginning of the Eclipse seen from a very well known place - your Stellarium picture quotes the Sun Azimuth as 234°09'15.3" (234.15425°) which might be different from the on-line Calculator value at 234.3°. And more significantly,

    the Stellarium ha at 37°13'51.6" substantially differs from the On-line Calculator value at 37°09.8' .

    Hence my question: if you can retrieve your early data, which exact coordinates did you use for "Stellarium" and for which "Stellarium time" did you request your Stellarium picture

    Kermit

       
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