static int Main(string[] args)
{
if (args.Length != 10)
{
Console.WriteLine(UsageText);
return(1);
}
// Validate and parse command line arguments.
double lat1 = ParseNumber("lat1", args[0]);
double lon1 = ParseNumber("lon1", args[1]);
double elv1 = ParseNumber("elv1", args[2]);
double az1 = ParseNumber("az1", args[3]);
double alt1 = ParseNumber("alt1", args[4]);
double lat2 = ParseNumber("lat2", args[5]);
double lon2 = ParseNumber("lon2", args[6]);
double elv2 = ParseNumber("elv2", args[7]);
double az2 = ParseNumber("az2", args[8]);
double alt2 = ParseNumber("alt2", args[9]);
var obs1 = new Observer(lat1, lon1, elv1);
var obs2 = new Observer(lat2, lon2, elv2);
// Use an arbitrary but consistent time for the Earth's rotation.
AstroTime time = new AstroTime(0.0);
// Convert geographic coordinates of the observers to vectors.
AstroVector pos1 = Astronomy.ObserverVector(time, obs1, EquatorEpoch.OfDate);
AstroVector pos2 = Astronomy.ObserverVector(time, obs2, EquatorEpoch.OfDate);
// Convert horizontal coordinates into unit direction vectors.
AstroVector dir1 = DirectionVector(time, obs1, alt1, az1);
AstroVector dir2 = DirectionVector(time, obs2, alt2, az2);
// Find the closest point between the skew lines.
return(Intersect(pos1, dir1, pos2, dir2));
}