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Moon Phase Angle |
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Calculates the moon phase angle
function Moon_Phase_Angle(date:TDateTime): extended;
Description Calculates the phase angle of the moon, the position of the bright limb on the moon hemisphere.
Hint This function returns a negative value for the second half of the month, everything after the full moon. Normally the phase angle is defined to be always position, so it have this value in this definition just use
PhaseAngle := Abs(Moon_Phase_Angle(date));
Reference This function is based upon chapter 48 (46) of "Astronomical Algorithms". |