diff options
Diffstat (limited to 'src/slalib/cs2c.f')
-rw-r--r-- | src/slalib/cs2c.f | 41 |
1 files changed, 41 insertions, 0 deletions
diff --git a/src/slalib/cs2c.f b/src/slalib/cs2c.f new file mode 100644 index 0000000..7d516c8 --- /dev/null +++ b/src/slalib/cs2c.f @@ -0,0 +1,41 @@ + SUBROUTINE sla_CS2C (A, B, V) +*+ +* - - - - - +* C S 2 C +* - - - - - +* +* Spherical coordinates to direction cosines (single precision) +* +* Given: +* A,B real spherical coordinates in radians +* (RA,Dec), (Long,Lat) etc +* +* Returned: +* V real(3) x,y,z unit vector +* +* The spherical coordinates are longitude (+ve anticlockwise +* looking from the +ve latitude pole) and latitude. The +* Cartesian coordinates are right handed, with the x axis +* at zero longitude and latitude, and the z axis at the +* +ve latitude pole. +* +* P.T.Wallace Starlink October 1984 +* +* Copyright (C) 1995 Rutherford Appleton Laboratory +*- + + IMPLICIT NONE + + REAL A,B,V(3) + + REAL COSB + + + + COSB=COS(B) + + V(1)=COS(A)*COSB + V(2)=SIN(A)*COSB + V(3)=SIN(B) + + END |