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    Re: Historical Lunars : take in account 'delta-T' or ignore it ?
    From: Frank Reed
    Date: 2009 Dec 23, 10:54 -0800

    Antoine, you asked:
    "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 ?"

    Yes. Just that simple. We parametrize it in terms of position angle because that can be counted as an observable parameter.


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