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Merge pull request #35 from jfcarr-astronomy/eclipses/solar
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Calculate -> Solar eclipse occurrence and circumstances.
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Jim Carr committed Dec 17, 2020
2 parents 29d63a1 + 3b44b2e commit c2f8d19
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12 changes: 12 additions & 0 deletions PALib.Tests/PAEclipses.cs
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Expand Up @@ -22,5 +22,17 @@ public void LunarEclipseCircumstances()
{
Assert.Equal((4, 4, 2015, 9, 0, 10, 16, 11, 55, 12, 1, 12, 7, 13, 46, 15, 1, 1.01), _paEclipses.LunarEclipseCircumstances(1, 4, 2015, false, 10));
}

[Fact]
public void SolarEclipseOccurrence()
{
Assert.Equal(("Solar eclipse certain", 20, 3, 2015), _paEclipses.SolarEclipseOccurrence(1, 4, 2015, false, 0));
}

[Fact]
public void SolarEclipseCircumstances()
{
Assert.Equal((20, 3, 2015, 8, 55, 9, 57, 10, 58, 1.016), _paEclipses.SolarEclipseCircumstances(20, 3, 2015, false, 0, 0, 68.65));
}
}
}
86 changes: 86 additions & 0 deletions PALib/PAEclipses.cs
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Expand Up @@ -122,5 +122,91 @@ public class PAEclipses

return (lunarEclipseCertainDateDay, lunarEclipseCertainDateMonth, lunarEclipseCertainDateYear, utStartPenPhaseHour, utStartPenPhaseMinutes, utStartUmbralPhaseHour, utStartUmbralPhaseMinutes, utStartTotalPhaseHour, utStartTotalPhaseMinutes, utMidEclipseHour, utMidEclipseMinutes, utEndTotalPhaseHour, utEndTotalPhaseMinutes, utEndUmbralPhaseHour, utEndUmbralPhaseMinutes, utEndPenPhaseHour, utEndPenPhaseMinutes, eclipseMagnitude);
}

/// <summary>
/// Determine if a solar eclipse is likely to occur.
/// </summary>
/// <returns>
/// <para>status -- One of "Solar eclipse certain", "Solar eclipse possible", or "No solar eclipse".</para>
/// <para>event_date_day -- Date of eclipse event (day).</para>
/// <para>event_date_month -- Date of eclipse event (month).</para>
/// <para>event_date_year -- Date of eclipse event (year).</para>
/// </returns>
public (string status, double eventDateDay, int eventDateMonth, int eventDateYear) SolarEclipseOccurrence(double localDateDay, int localDateMonth, int localDateYear, bool isDaylightSaving, int zoneCorrectionHours)
{
var daylightSaving = (isDaylightSaving) ? 1 : 0;

var julianDateOfNewMoon = PAMacros.NewMoon(daylightSaving, zoneCorrectionHours, localDateDay, localDateMonth, localDateYear);
var gDateOfNewMoonDay = PAMacros.JulianDateDay(julianDateOfNewMoon);
var integerDay = (gDateOfNewMoonDay).Floor();
var gDateOfNewMoonMonth = PAMacros.JulianDateMonth(julianDateOfNewMoon);
var gDateOfNewMoonYear = PAMacros.JulianDateYear(julianDateOfNewMoon);
var utOfNewMoonHours = gDateOfNewMoonDay - integerDay;

var localCivilDateDay = PAMacros.UniversalTime_LocalCivilDay(utOfNewMoonHours, 0.0, 0.0, daylightSaving, zoneCorrectionHours, integerDay, gDateOfNewMoonMonth, gDateOfNewMoonYear);
var localCivilDateMonth = PAMacros.UniversalTime_LocalCivilMonth(utOfNewMoonHours, 0.0, 0.0, daylightSaving, zoneCorrectionHours, integerDay, gDateOfNewMoonMonth, gDateOfNewMoonYear);
var localCivilDateYear = PAMacros.UniversalTime_LocalCivilYear(utOfNewMoonHours, 0.0, 0.0, daylightSaving, zoneCorrectionHours, integerDay, gDateOfNewMoonMonth, gDateOfNewMoonYear);

var eclipseOccurrence = PAMacros.SolarEclipseOccurrence(daylightSaving, zoneCorrectionHours, localDateDay, localDateMonth, localDateYear);

var status = eclipseOccurrence;
var eventDateDay = localCivilDateDay;
var eventDateMonth = localCivilDateMonth;
var eventDateYear = localCivilDateYear;

return (status, eventDateDay, eventDateMonth, eventDateYear);
}

/// <summary>
/// Calculate the circumstances of a solar eclipse.
/// </summary>
/// <returns>
/// <para>solarEclipseCertainDateDay -- Solar eclipse date (day)</para>
/// <para>solarEclipseCertainDateMonth -- Solar eclipse date (month)</para>
/// <para>solarEclipseCertainDateYear -- Solar eclipse date (year)</para>
/// <para>utFirstContactHour -- First contact of shadow (hour)</para>
/// <para>utFirstContactMinutes -- First contact of shadow (minutes)</para>
/// <para>utMidEclipseHour -- Mid-eclipse (hour)</para>
/// <para>utMidEclipseMinutes -- Mid-eclipse (minutes)</para>
/// <para>utLastContactHour -- Last contact of shadow (hour)</para>
/// <para>utLastContactMinutes -- Last contact of shadow (minutes)</para>
/// <para>eclipseMagnitude -- Eclipse magnitude</para>
/// </returns>
public (double solarEclipseCertainDateDay, int solarEclipseCertainDateMonth, int solarEclipseCertainDateYear, double utFirstContactHour, double utFirstContactMinutes, double utMidEclipseHour, double utMidEclipseMinutes, double utLastContactHour, double utLastContactMinutes, double eclipseMagnitude) SolarEclipseCircumstances(double localDateDay, int localDateMonth, int localDateYear, bool isDaylightSaving, int zoneCorrectionHours, double geogLongitudeDeg, double geogLatitudeDeg)
{
var daylightSaving = (isDaylightSaving) ? 1 : 0;

var julianDateOfNewMoon = PAMacros.NewMoon(daylightSaving, zoneCorrectionHours, localDateDay, localDateMonth, localDateYear);
var gDateOfNewMoonDay = PAMacros.JulianDateDay(julianDateOfNewMoon);
var integerDay = (gDateOfNewMoonDay).Floor();
var gDateOfNewMoonMonth = PAMacros.JulianDateMonth(julianDateOfNewMoon);
var gDateOfNewMoonYear = PAMacros.JulianDateYear(julianDateOfNewMoon);
var utOfNewMoonHours = gDateOfNewMoonDay - integerDay;
var localCivilDateDay = PAMacros.UniversalTime_LocalCivilDay(utOfNewMoonHours, 0.0, 0.0, daylightSaving, zoneCorrectionHours, integerDay, gDateOfNewMoonMonth, gDateOfNewMoonYear);
var localCivilDateMonth = PAMacros.UniversalTime_LocalCivilMonth(utOfNewMoonHours, 0.0, 0.0, daylightSaving, zoneCorrectionHours, integerDay, gDateOfNewMoonMonth, gDateOfNewMoonYear);
var localCivilDateYear = PAMacros.UniversalTime_LocalCivilYear(utOfNewMoonHours, 0.0, 0.0, daylightSaving, zoneCorrectionHours, integerDay, gDateOfNewMoonMonth, gDateOfNewMoonYear);

var utMaxEclipse = PAMacros.UTMaxSolarEclipse(localDateDay, localDateMonth, localDateYear, daylightSaving, zoneCorrectionHours, geogLongitudeDeg, geogLatitudeDeg);
var utFirstContact = PAMacros.UTFirstContactSolarEclipse(localDateDay, localDateMonth, localDateYear, daylightSaving, zoneCorrectionHours, geogLongitudeDeg, geogLatitudeDeg);
var utLastContact = PAMacros.UTLastContactSolarEclipse(localDateDay, localDateMonth, localDateYear, daylightSaving, zoneCorrectionHours, geogLongitudeDeg, geogLatitudeDeg);
var magnitude = PAMacros.MagSolarEclipse(localDateDay, localDateMonth, localDateYear, daylightSaving, zoneCorrectionHours, geogLongitudeDeg, geogLatitudeDeg);

var solarEclipseCertainDateDay = localCivilDateDay;
var solarEclipseCertainDateMonth = localCivilDateMonth;
var solarEclipseCertainDateYear = localCivilDateYear;

var utFirstContactHour = (utFirstContact == -99.0) ? -99.0 : PAMacros.DecimalHoursHour(utFirstContact + 0.008333);
var utFirstContactMinutes = (utFirstContact == -99.0) ? -99.0 : PAMacros.DecimalHoursMinute(utFirstContact + 0.008333);

var utMidEclipseHour = (utMaxEclipse == -99.0) ? -99.0 : PAMacros.DecimalHoursHour(utMaxEclipse + 0.008333);
var utMidEclipseMinutes = (utMaxEclipse == -99.0) ? -99.0 : PAMacros.DecimalHoursMinute(utMaxEclipse + 0.008333);

var utLastContactHour = (utLastContact == -99.0) ? -99.0 : PAMacros.DecimalHoursHour(utLastContact + 0.008333);
var utLastContactMinutes = (utLastContact == -99.0) ? -99.0 : PAMacros.DecimalHoursMinute(utLastContact + 0.008333);

var eclipseMagnitude = (magnitude == -99.0) ? -99.0 : Math.Round(magnitude, 3);

return (solarEclipseCertainDateDay, solarEclipseCertainDateMonth, solarEclipseCertainDateYear, utFirstContactHour, utFirstContactMinutes, utMidEclipseHour, utMidEclipseMinutes, utLastContactHour, utLastContactMinutes, eclipseMagnitude);
}
}
}
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