slaPrec -

SYNOPSYS

void slaPrec(ep0, ep1, rmatp)

PARAMETERS

double ep0
double ep1
double ( *rmatp

DESCRIPTION


  Form the matrix of precession between two epochs (IAU 1976, FK5).

  (double precision)

Given

     ep0    double         beginning epoch
     ep1    double         ending epoch

Returned

     rmatp  double[3][3]   precession matrix

Notes


  1)  The epochs are TDB (loosely ET) Julian epochs.

  2)  The matrix is in the sense   v(ep1)  =  rmatp * v(ep0) .

References

     Lieske,J.H., 1979. Astron. Astrophys.,73,282.
          equations (6) & (7), p283.
     Kaplan,G.H., 1981. USNO circular no. 163, pa2.

Called

 slaDeuler

  Defined in slamac.h:  DAS2R

  P.T.Wallace   Starlink   31 October 1993

SEE ALSO