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NOVAS31DLight Method

Returns the difference in light-time, for a star, between the barycenter of the solar system and the observer (or the geocenter).

Namespace:  ASCOM.Astrometry.NOVAS
Assembly:  ASCOM.Astrometry (in ASCOM.Astrometry.dll) Version: 3c9121baba46811fe6e53a58a05935662261416d
public double DLight(
	double[] Pos1,
	double[] PosObs


Type: SystemDouble
Position vector of star, with respect to origin at solar system barycenter.
Type: SystemDouble
Position vector of observer (or the geocenter), with respect to origin at solar system barycenter, components in AU.

Return Value

Type: Double
Difference in light time, in the sense star to barycenter minus star to earth, in days.
Alternatively, this function returns the light-time from the observer (or the geocenter) to a point on a light ray that is closest to a specific solar system body. For this purpose, 'Pos1' is the position vector toward observed object, with respect to origin at observer (or the geocenter); 'PosObs' is the position vector of solar system body, with respect to origin at observer (or the geocenter), components in AU; and the returned value is the light time to point on line defined by 'Pos1' that is closest to solar system body (positive if light passes body before hitting observer, i.e., if 'Pos1' is within 90 degrees of 'PosObs').
See Also