/// <summary>
/// Calculate Moon phase and position angle of bright limb.
/// </summary>
/// <returns>
/// <para>moonPhase -- Phase of Moon, between 0 and 1, where 0 is New and 1 is Full.</para>
/// <para>paBrightLimbDeg -- Position angle of the bright limb (degrees)</para>
/// </returns>
public (double moonPhase, double paBrightLimbDeg) MoonPhase(double lctHour, double lctMin, double lctSec, bool isDaylightSaving, int zoneCorrectionHours, double localDateDay, int localDateMonth, int localDateYear, PAAccuracyLevel accuracyLevel)
{
var daylightSaving = (isDaylightSaving) ? 1 : 0;
var gdateDay = PAMacros.LocalCivilTimeGreenwichDay(lctHour, lctMin, lctSec, daylightSaving, zoneCorrectionHours, localDateDay, localDateMonth, localDateYear);
var gdateMonth = PAMacros.LocalCivilTimeGreenwichMonth(lctHour, lctMin, lctSec, daylightSaving, zoneCorrectionHours, localDateDay, localDateMonth, localDateYear);
var gdateYear = PAMacros.LocalCivilTimeGreenwichYear(lctHour, lctMin, lctSec, daylightSaving, zoneCorrectionHours, localDateDay, localDateMonth, localDateYear);
var sunLongDeg = PAMacros.SunLong(lctHour, lctMin, lctSec, daylightSaving, zoneCorrectionHours, localDateDay, localDateMonth, localDateYear);
var moonResult = PAMacros.MoonLongLatHP(lctHour, lctMin, lctSec, daylightSaving, zoneCorrectionHours, localDateDay, localDateMonth, localDateYear);
var dRad = (moonResult.moonLongDeg - sunLongDeg).ToRadians();
var moonPhase1 = (accuracyLevel == PAAccuracyLevel.Precise) ? PAMacros.MoonPhase(lctHour, lctMin, lctSec, daylightSaving, zoneCorrectionHours, localDateDay, localDateMonth, localDateYear) : (1.0 - (dRad).Cosine()) / 2.0;
var sunRARad = (PAMacros.EcRA(sunLongDeg, 0, 0, 0, 0, 0, gdateDay, gdateMonth, gdateYear)).ToRadians();
var moonRARad = (PAMacros.EcRA(moonResult.moonLongDeg, 0, 0, moonResult.moonLatDeg, 0, 0, gdateDay, gdateMonth, gdateYear)).ToRadians();
var sunDecRad = (PAMacros.EcDec(sunLongDeg, 0, 0, 0, 0, 0, gdateDay, gdateMonth, gdateYear)).ToRadians();
var moonDecRad = (PAMacros.EcDec(moonResult.moonLongDeg, 0, 0, moonResult.moonLatDeg, 0, 0, gdateDay, gdateMonth, gdateYear)).ToRadians();
var y = (sunDecRad).Cosine() * (sunRARad - moonRARad).Sine();
var x = (moonDecRad).Cosine() * (sunDecRad).Sine() - (moonDecRad).Sine() * (sunDecRad).Cosine() * (sunRARad - moonRARad).Cosine();
var chiDeg = PAMacros.Degrees(y.AngleTangent2(x));
var moonPhase = Math.Round(moonPhase1, 2);
var paBrightLimbDeg = Math.Round(chiDeg, 2);
return(moonPhase, paBrightLimbDeg);
}