public TimeSpan(ITime2 timeHorizon)
 {
     _start = new TimeStamp(timeHorizon.StampAsModifiedJulianDay);
     _end = new TimeStamp(timeHorizon.StampAsModifiedJulianDay + timeHorizon.DurationInDays);
 }
            public static ITime1 ToTime1(ITime2 time2)
            {
                if (time2.DurationInDays == 0)
                    return new TimeStamp(time2.StampAsModifiedJulianDay);

                return new TimeSpan(
                    new TimeStamp(time2.StampAsModifiedJulianDay),
                    new TimeStamp(time2.StampAsModifiedJulianDay + time2.DurationInDays));
            }