Exemplo n.º 1
0
        public static Apogee GetApogeeEvents(DateTime d)
        {
            //Iterate in 5 month increments due to formula variations.
            //Determine closest events to date.
            //apo1 is last date
            //apo2 is next date

            //integrity for new date.
            if (d.Year <= 0001)
            {
                return(new Apogee(new PerigeeApogee(new DateTime(), 0, new Distance(0)), new PerigeeApogee(new DateTime(), 0, new Distance(0))));
            }

            PerigeeApogee apo1 = MoonPerigeeOrApogee(d.AddDays(-45), MoonDistanceType.Apogee);
            PerigeeApogee apo2 = MoonPerigeeOrApogee(d.AddDays(-45), MoonDistanceType.Apogee);

            for (int x = -30; x <= 45; x += 15)
            {
                PerigeeApogee t = MoonPerigeeOrApogee(d.AddDays(x), MoonDistanceType.Apogee);
                //Find next apogee after specified date
                if (t.Date > apo2.Date && t.Date >= d)
                {
                    apo2 = t;
                    break;
                }
                //Find last apogee before specified date
                if (t.Date > apo1.Date && t.Date < d)
                {
                    apo1 = t;
                    apo2 = t;
                }
            }
            return(new Apogee(apo1, apo2));
        }
Exemplo n.º 2
0
        private PerigeeApogee Get_Correct_Slipped_Date(PerigeeApogee actual, PerigeeApogee pre, PerigeeApogee post, int i)
        {
            switch (i)
            {
            case 0:
                return(pre);

            case 1:
                return(actual);

            case 2:
                return(post);

            default:
                return(actual);
            }
        }
Exemplo n.º 3
0
        public static Perigee GetPerigeeEvents(DateTime d)
        {
            //Iterate in 15 day increments due to formula variations.
            //Determine closest events to date.
            //per1 is last date
            //per2 is next date

            //integrity for new date.
            if (d.Year <= 0001)
            {
                return(new Perigee(new PerigeeApogee(new DateTime(), 0, new Distance(0)), new PerigeeApogee(new DateTime(), 0, new Distance(0))));
            }
            //Start at lowest increment
            PerigeeApogee per1 = MoonPerigeeOrApogee(d.AddDays(-45), MoonDistanceType.Perigee);
            PerigeeApogee per2 = MoonPerigeeOrApogee(d.AddDays(-45), MoonDistanceType.Perigee);

            for (int x = -30; x <= 45; x += 15)
            {
                //used for comparison
                PerigeeApogee t = MoonPerigeeOrApogee(d.AddDays(x), MoonDistanceType.Perigee);

                //Find the next pergiee after specified date
                if (t.Date > per2.Date && t.Date >= d)
                {
                    per2 = t;
                    break;
                }
                //Find last perigee before specified date
                if (t.Date > per1.Date && t.Date < d)
                {
                    per1 = t;
                    per2 = t;
                }
            }
            return(new Perigee(per1, per2));
        }
Exemplo n.º 4
0
        //v1.1.3 Formulas
        //The following formulas are either additions
        //or conversions of SunCalcs formulas into Meeus

        /// <summary>
        /// Grabs Perigee or Apogee of Moon based on specified time.
        /// Results will return event just before, or just after specified DateTime
        /// </summary>
        /// <param name="d">DateTime</param>
        /// <param name="md">Event Type</param>
        /// <returns>PerigeeApogee</returns>
        private static PerigeeApogee MoonPerigeeOrApogee(DateTime d, MoonDistanceType md)
        {
            //Perigee & Apogee Algorithms from Jean Meeus Astronomical Algorithms Ch. 50

            //50.1
            //JDE = 2451534.6698 + 27.55454989 * k
            //                     -0.0006691 * Math.Pow(T,2)
            //                     -0.000.01098 * Math.Pow(T,3)
            //                     -0.0000000052 * Math.Pow(T,4)

            //50.2
            //K approx = (yv - 1999.97)*13.2555
            //yv is the year + percentage of days that have occured in the year. 1998 Oct 1 is approx 1998.75
            //k ending in .0 represent perigee and .5 apogee. Anything > .5 is an error.

            //50.3
            //T = k/1325.55

            double yt = 365; //days in year

            if (DateTime.IsLeapYear(d.Year))
            {
                yt = 366;
            }                                     //days in year if leap year
            double f  = d.DayOfYear / yt;         //Get percentage of year that as passed
            double yv = d.Year + f;               //add percentage of year passed to year.
            double k  = (yv - 1999.97) * 13.2555; //find approximate k using formula 50.2

            //Set k decimal based on apogee or perigee
            if (md == MoonDistanceType.Apogee)
            {
                k = Math.Floor(k) + .5;
            }
            else
            {
                k = Math.Floor(k);
            }

            //Find T using formula 50.3
            double T = k / 1325.55;
            //Find JDE using formula 50.1
            double JDE = 2451534.6698 + 27.55454989 * k -
                         0.0006691 * Math.Pow(T, 2) -
                         0.00001098 * Math.Pow(T, 3) -
                         0.0000000052 * Math.Pow(T, 4);

            //Find Moon's mean elongation at time JDE.
            double D = 171.9179 + 335.9106046 * k -
                       0.0100383 * Math.Pow(T, 2) -
                       0.00001156 * Math.Pow(T, 3) +
                       0.000000055 * Math.Pow(T, 4);

            //Find Sun's mean anomaly at time JDE
            double M = 347.3477 + 27.1577721 * k -
                       0.0008130 * Math.Pow(T, 2) -
                       0.0000010 * Math.Pow(T, 3);


            //Find Moon's argument of latitude at Time JDE
            double F = 316.6109 + 364.5287911 * k -
                       0.0125053 * Math.Pow(T, 2) -
                       0.0000148 * Math.Pow(T, 3);

            //Normalize DMF to a 0-360 degree number
            D %= 360;
            if (D < 0)
            {
                D += 360;
            }
            M %= 360;
            if (M < 0)
            {
                M += 360;
            }
            F %= 360;
            if (F < 0)
            {
                F += 360;
            }

            //Convert DMF to radians
            D = D * Math.PI / 180;
            M = M * Math.PI / 180;
            F = F * Math.PI / 180;
            double termsA;

            //Find Terms A from Table 50.A
            if (md == MoonDistanceType.Apogee)
            {
                termsA = MeeusTables.ApogeeTermsA(D, M, F, T);
            }
            else
            {
                termsA = MeeusTables.PerigeeTermsA(D, M, F, T);
            }
            JDE += termsA;
            double termsB;

            if (md == MoonDistanceType.Apogee)
            {
                termsB = MeeusTables.ApogeeTermsB(D, M, F, T);
            }
            else
            {
                termsB = MeeusTables.PerigeeTermsB(D, M, F, T);
            }
            //Convert julian back to date
            DateTime date = JulianConversions.GetDate_FromJulian(JDE).Value;
            //Obtain distance
            Distance dist = GetMoonDistance(date);

            PerigeeApogee ap = new PerigeeApogee(date, termsB, dist);

            return(ap);
        }
 /// <summary>
 /// Initializes an Apogee object.
 /// </summary>
 /// <param name="last"></param>
 /// <param name="next"></param>
 public Apogee(PerigeeApogee last, PerigeeApogee next)
 {
     lastApogee = last;
     nextApogee = next;
 }