THIS SUBROUTINE RETURNS THE DIFFERENCE IN LIGHT-TIME, FOR A STAR, BETWEEN THE BARYCENTER OF THE SOLAR SYSTEM AND THE OBSERVER (OR THE GEOCENTER).
POS1 = POSITION VECTOR OF STAR, WITH RESPECT TO ORIGIN AT
SOLAR SYSTEM BARYCENTER (IN)
PE = POSITION VECTOR OF OBSERVER (OR THE GEOCENTER),
WITH RESPECT TO ORIGIN AT SOLAR SYSTEM BARYCENTER,
COMPONENTS IN AU (IN)
DIFLT = DIFFERENCE IN LIGHT TIME, IN THE SENSE STAR TO
BARYCENTER MINUS STAR TO EARTH, IN DAYS (OUT)
-OR-
THIS SUBROUTINE 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.
POS1 = POSITION VECTOR TOWARD OBSERVED OBJECT, WITH RESPECT
TO ORIGIN AT OBSERVER (OR THE GEOCENTER) (IN)
PE = POSITION VECTOR OF SOLAR SYSTEM BODY, WITH RESPECT
TO ORIGIN AT OBSERVER (OR THE GEOCENTER), COMPONENTS
IN AU (IN)
DIFLT = 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 PE)(OUT)
Type | Intent | Optional | Attributes | Name | ||
---|---|---|---|---|---|---|
real(kind=wp), | dimension(3) | :: | pos1 | |||
real(kind=wp), | dimension(3) | :: | pe | |||
real(kind=wp) | :: | diflt |