public double Horizon { get; }There are a number of standard Horizon values you can use:
| value | meaning |
|---|---|
| SunriseAltitude, -51' | The altitude used for sunrise and sunset calculations, taking into account atmospheric distortion. |
| CivilTwilightAltitude, -6° | When the sun is above this altitude, you are in twilight as generally understood. |
| NauticalTwilightAltitude, -12° | Above this altitude, mariners at sea will detect the sun's glow at the horizon with the unaided eye. |
| AstronomicalTwilightAltitude, -18° | Above this altitude, ground-based astronomical instruments can detect the scattering of the sun's light in the atmosphere. |