Protected Function BerechneJD(ByVal datum As DateTime) As Decimal
 
		Dim jahr As Integer = datum.Year
		Dim monat As Integer = datum.Month
		If monat <= 2 Then
			jahr -= 1
			monat += 12
		End If
 
		Dim stunde As Integer = datum.Hour
		Dim minute As Integer = datum.Minute
		Dim sekunde As Integer = datum.Second
		Dim h As Decimal = CDec(stunde / 24 + minute / 1440 + sekunde / 86400)
 
		Dim b As Decimal
		If _gKalender = True Then
			Dim a As Decimal = Math.Floor(jahr / 100D)
			b = 2 - a + Math.Floor(a / 4D)
		Else
			b = 0
		End If
 
		Dim tag As Integer = datum.Day
		Return CDec(Math.Floor(365.25D * (jahr + 4716)) + Math.Floor(30.6001D * ( _
  monat + 1)) + tag + h + b - 1524.5D)
 
	End Function

	Public ReadOnly Property JulianischesDatum(ByVal typ As JDType) As Decimal
		Get
			Select Case typ
				Case JDType.JD	' Julianisches Datum (JD)
					Return _jDatum
 
				Case JDType.CJD ' Chronologisches JD
					Return Math.Floor(_jDatum + 0.5D)
				Case JDType.MJD ' Modifiziertes JD
					Return _jDatum - 2400000.5D
 
				Case JDType.J1900	' Standardepoche J1900
					Return _jDatum - 2415020D
				Case JDType.J2000	' Standardepoche J2000
					Return _jDatum - 2451545D
 
				Case JDType.B1850	' Besseljahr B1850
					Return _jDatum - 2396758.203D
				Case JDType.B1900	' Besseljahr B1900
					Return _jDatum - 2415020.313D
				Case JDType.B1950	' Besseljahr B1950
					Return _jDatum - 2433282.423D
				Case JDType.B2000	' Besseljahr B2000
					Return _jDatum - 2451544.533D
				Case JDType.B2050	' Besseljahr B2050
					Return _jDatum - 2469806.643D
				Case JDType.B2100	' Besseljahr B2100
					Return _jDatum - 2488068.753D
			End Select
			Return _jDatum
		End Get
	End Property

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"There's never enough time to do all the nothing you want."
(Calvin and Hobbes)