/// <summary>
/// Convert elevation angle to zone time.
/// </summary>
/// <param name="e">Equator coordinates.</param>
/// <param name="angle">Elevation angle.</param>
/// <param name="latitude">Local latitude.</param>
/// <param name="longitude">Local longitude.</param>
/// <param name="date">Date.</param>
/// <param name="localTimeZone">Local time zone.</param>
/// <returns>Zone time in degree.</returns>
public static double[] ElevationAngle2Time(Equator e, double angle, double latitude, double longitude, DateTime date, TimeZoneInfo localTimeZone)
{
double ra = e.RA;
double dec = e.Dec;
double sinH = Math.Sin(angle * (Math.PI / 180.0));
double cosT = (sinH - Math.Sin(latitude * Math.PI / 180.0) * Math.Sin(dec * Math.PI / 180.0)) / (Math.Cos(latitude * Math.PI / 180.0) * Math.Cos(dec * Math.PI / 180.0));
if (Math.Abs(cosT) > 1)
{
return(new double[] { 0, 0 });
}
double T = Math.Acos(cosT) * 180.0 / Math.PI;
double t1 = 360 - T;
double t2 = T;
double localSiderealTime1 = t1 + ra;
double zoneTime1 = SiderealTime.SiderealTime2ZoneTime(localSiderealTime1, date, localTimeZone, longitude);
double localSiderealTime2 = t2 + ra;
double zoneTime2 = SiderealTime.SiderealTime2ZoneTime(localSiderealTime2, date, localTimeZone, longitude);
return(new double[] { zoneTime1, zoneTime2 });
}
/// <summary>
/// Calculate local hour angle.
/// </summary>
/// <param name="time">Local time.</param>
/// <param name="RA">Right ascension.</param>
/// <param name="longitude">Local longitude.</param>
/// <returns>The hour angle.</returns>
public static double GetHourAngle(DateTime time, double RA, double longitude)
{
double ra = RA;
double localSiderealTime = SiderealTime.LocalMeanSiderealTime(time, TimeZoneInfo.Local, longitude);
double ha = localSiderealTime - ra;
return(ha);
}
