From d54fe7c1f704a63824c5bfa0ece65245572e9b27 Mon Sep 17 00:00:00 2001 From: Joseph Hunkeler Date: Wed, 4 Mar 2015 21:21:30 -0500 Subject: Initial commit --- src/slalib/pav.f | 53 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 53 insertions(+) create mode 100644 src/slalib/pav.f (limited to 'src/slalib/pav.f') diff --git a/src/slalib/pav.f b/src/slalib/pav.f new file mode 100644 index 0000000..7eb1c12 --- /dev/null +++ b/src/slalib/pav.f @@ -0,0 +1,53 @@ + REAL FUNCTION sla_PAV ( V1, V2 ) +*+ +* - - - - +* P A V +* - - - - +* +* Position angle of one celestial direction with respect to another. +* +* (single precision) +* +* Given: +* V1 r(3) direction cosines of one point +* V2 r(3) direction cosines of the other point +* +* (The coordinate frames correspond to RA,Dec, Long,Lat etc.) +* +* The result is the bearing (position angle), in radians, of point +* V2 with respect to point V1. It is in the range +/- pi. The +* sense is such that if V2 is a small distance east of V1, the +* bearing is about +pi/2. Zero is returned if the two points +* are coincident. +* +* V1 and V2 do not have to be unit vectors. +* +* The routine sla_BEAR performs an equivalent function except +* that the points are specified in the form of spherical +* coordinates. +* +* Called: sla_DPAV +* +* Patrick Wallace Starlink 23 May 1997 +* +* Copyright (C) 1997 Rutherford Appleton Laboratory +*- + + IMPLICIT NONE + + REAL V1(3),V2(3) + + INTEGER I + DOUBLE PRECISION D1(3),D2(3) + + DOUBLE PRECISION sla_DPAV + + +* Call the double precision version + DO I=1,3 + D1(I)=V1(I) + D2(I)=V2(I) + END DO + sla_PAV=sla_DPAV(D1,D2) + + END -- cgit