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    Re: Historical Lunars : take in account 'delta-T' or ignore it ?
    From: Antoine Couëtte
    Date: 2009 Dec 23, 09:44 -0800

    This post makes a specific reference to Navlist 11182 dtd 15 Dec 2009 by Frank E. Reed


    Frank, you wrote :


    This is nothing more than "refractional flattening". ./././. The difference gives you the refractional flattening for the upper half of the Moon (very nearly equal to half of the total refractional flattening). This maximal amount then varies by cos^2(position angle) as you work your way around the limb. ./././.


    Just one question then since you might reply immediately. It might save me the time to recompute it ?

    Am I right in guessing that the formula given hereabove - cos^2(position angle) - is one parametric formula (among a few others) to define exactly an ELLIPSE ? Such an ellipse would have its semi-major axis horizontal and (almost) equal to semi-diameter, and its semi-minor axis vertical and equal to half the distance between apparent refracted upper and lower Limbs ?

    Thank you for your Kind Attention and reply.

    Merry Christmas to you, and to all


    Antoine M. "Kermit" Couette

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