subroutine pe2xy(mjd,dpsi,deps,X,Y) C-------------------------------------------------------------------------C C C C Conversion of total dpsi, deps to X, Y C C C C-------------------------------------------------------------------------C C C C References : C C IERS Conventions 2000, chap. 5 C C C C-------------------------------------------------------------------------C C C C Input : C C mjd : time in mjd C C dpsi, deps : total nutation angles in arcsec C C = model [IAU1980] + dp, de [IAU1980] C C or model [IAU2000] + dp, de [IAU2000] C C Output : C C X, Y : CIP coordinates in the ICRF in arcsec C C C C-------------------------------------------------------------------------C C C C Subroutine interface : none C C C C-------------------------------------------------------------------------C C C C Author : Sebastien Lambert (Sebastien.Lambert@obspm.fr) C C Last modified : 23/05/03 C C C C-------------------------------------------------------------------------C implicit none C Input variables double precision :: mjd,dpsi,deps C Output variables double precision :: X,Y C Other variables double precision :: deps1,dpsi1 double precision :: psiA,omeA,epsA,chiA double precision :: ksi0,eta0,dalpha0 double precision :: psi,omega double precision :: Xb,Yb double precision :: jc,eps0 double precision, parameter :: a2r=4.84813681109535993D-6 double precision, parameter :: r2a=2.06264806247096355D+5 C Julian centuries from J2000.0 jc=(mjd-51544.5D0)/36525.D0 C Lieske et al. (1977) expressions in arcsec and converted in radians eps0=84381.448D0 psiA=5038.47875D0*jc . -1.07259D0*jc*jc . -0.001147D0*jc*jc*jc omeA=eps0 . -0.02524D0*jc . +0.05127D0*jc*jc . -0.007726D0*jc*jc*jc epsA=eps0 . -46.8402D0*jc . -0.00059D0*jc*jc . +0.001813D0*jc*jc*jc chiA=10.5526D0*jc . -2.38064D0*jc*jc . -0.001125D0*jc*jc*jc eps0=eps0*a2r psiA=psiA*a2r omeA=omeA*a2r epsA=epsA*a2r chiA=chiA*a2r C Right ascension of the mean equinox of J2000.0 in the ICRS in radians dalpha0=-0.01460D0*a2r C Celestial pole offsets at J2000.0 in radians ksi0=-0.0166170D0*a2r eta0=-0.0068192D0*a2r C Total nutation angles dpsi, deps in radians dpsi=dpsi*a2r deps=deps*a2r C Chapter 5, equation (22) dpsi1=(dpsi*dsin(epsA)*dcos(chiA)-deps*dsin(chiA))/dsin(omeA) deps1=dpsi*dsin(epsA)*dsin(chiA)+deps*dcos(chiA) C Chapter 5, equation (21) omega=omeA+deps1 psi=psiA+dpsi1 C Chapter 5, equation (20) Xb=dsin(omega)*dsin(psi) Yb=-dsin(eps0)*dcos(omega)+dcos(eps0)*dsin(omega)*dcos(psi) C Chapter 5, equation (18) X=Xb+ksi0-dalpha0*Yb Y=Yb+eta0+dalpha0*Xb C Conversion radians in arcsec X=X*r2a Y=Y*r2a end