
      FUNCTION CEPIERS96(DMJD,TRI,TFCN,TRATE,TCONST,KPAR)	

!     Computes the correction to ADD to dPsi, dEpsilon that are referred to 
!     IAU 1980 Nutation and the IAU 1976 Precession in order to transform
!     them into the IERS Conventions (1996) Nutation for MJD=DMJD(R*8), 
!     including:
!     - the reference to the ICRF pole (dPsi_0 = -43.1 mas, dEps_0 = -5.1 mas)
!     - a precession of -2.99 mas/year, 
!     - an obliquity rate of -0.24 mas/year,
!     - an empirical FCN term, based on 1992-1996 (period=433 days).

      DOUBLE PRECISION DMJD,T,AP,AM,AD,W,DPT,H
	Parameter (NT=25) ! -> ira a 375)
      DIMENSION TRI(NT),IARG(NT,11),AM(NT,2,2),AP(11),AD(11),AL(2,2)

C     Corrections en longitude (kpar=1) -  A AJOUTER AUX VALEURS
c		     obliquite (kpar=2)    RAPPORTEES A UAI 1980
c	en 0.001", a la date DMJD (MJD), REAL*8
!							
C     	Selon Souchay et al. (1995)
!	- les 25 termes les plus grands (dPsi.sinE et dEps confondus, 
!  luni-solaires (LS, periode en jours) et planetaires (Pl, periode en annees), 
c	- avec <Psi*sinE>, <Epsilon>  pole moyen IERS/UAI,
c	- et "nutation libre du noyau" empirique,de periode 433 jours.

      DATA ((iarg(I,J),J=1,11),(am(I,1,J),J=1,2),(am(I,2,J),J=1,2),  ! Periode
     .     I=  1, 10) / 
     . 1, 0, 2, 0, 1, 0,  0, 0, 0, 0, 0,-0.063, 0.012, 0.008,-0.065, !   9.12 LS.
     . 1, 0, 2, 0, 2, 0,  0, 0, 0, 0, 0,-0.036, 0.081, 0.037,-0.004, !   9.13 LS.
     . 0, 0, 2, 0, 1, 0,  0, 0, 0, 0, 0,-0.152, 0.037, 0.034, 0.076, !  13.63 LS.
     . 0, 0, 2, 0, 2, 0,  0, 0, 0, 0, 0,-0.318, 0.288, 0.145, 0.164, !  13.66 LS.
     . 0, 0, 0, 2, 0, 0,  0, 0, 0, 0, 0, 0.036,-0.016, 0.003, 0.075, !  14.77 LS.
     .-1, 0, 2, 0, 1, 0,  0, 0, 0, 0, 0,-0.056, 0.001, 0.000,-0.076, !  26.98 LS.
     . 1, 0, 0, 0, 0, 0,  0, 0, 0, 0, 0,-0.082,-0.098, 0.039, 0.013, !  27.55 LS.
     .-1, 0, 0, 2, 0, 0,  0, 0, 0, 0, 0,-0.100,-0.019, 0.009,-0.027, !  31.81 LS.
     .-1, 0, 0, 2, 1, 0,  0, 0, 0, 0, 0,-0.083, 0.001, 0.000,-0.001, !  31.96 LS.
     . 0, 0,-2, 2,-1, 0,  0, 0, 0, 0, 0, 0.080, 0.018,-0.004, 0.103/ ! 177.84 LS.

      DATA ((iarg(I,J),J=1,11),(am(I,1,J),J=1,2),(am(I,2,J),J=1,2),
     .     I= 11, 20) / 
     . 0, 0, 2,-2, 2, 0,  0, 0, 0, 0, 0, 1.685,-1.398,-0.463,-0.541, ! 182.62 LS.
     . 0, 0,-2, 2,-3, 0,  0, 0, 0, 0, 0,-0.123, 0.000, 0.000,-0.020, ! 187.66 LS.
     . 0, 0, 0, 0, 0, 2, -2, 0, 0, 0, 0,-0.060, 0.000, 0.000, 0.000, !   0.80 Pl.
     . 0,-1, 2,-2, 2, 0,  0, 0, 0, 0, 0,-0.117, 0.000, 0.012,-0.091, ! 365.22 LS.
     . 0, 1, 0, 0, 0, 0,  0, 0, 0, 0, 0, 4.944, 1.121,-0.198, 1.990, ! 365.26 LS.
     . 0, 0, 0, 0, 0, 0,  1, 0,-1, 0, 0,-0.123,-0.003, 0.000, 0.000, !   1.09 Pl.
     . 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0.153, 0.000, 0.000, 0.000, !   1.60 Pl.
     . 0, 0, 0, 0, 0, 0,  0, 0, 2, 0, 2,-0.116, 0.003, 0.000, 0.051, !   5.92 Pl.
     . 0, 0, 0, 0, 0, 3, -5, 0, 0, 0,-2, 0.211, 0.000, 0.000, 0.096, !   8.10 Pl.
     .-1, 0, 1, 0, 1, 0,  0, 0, 0, 0, 0, 0.000,-0.105,-0.089, 0.000/ !3231.50 LS.

      DATA ((iarg(I,J),J=1,11),(am(I,1,J),J=1,2),(am(I,2,J),J=1,2),
     .     I= 21, 25) / 
     . 0, 0, 0, 0, 2, 0,  0, 0, 0, 0, 0, 1.228,-0.071,-0.029,-0.246, !3399.19 LS.
     .-1, 1, 0, 1, 1, 0,  0, 0, 0, 0, 0, 0.132, 0.000, 0.000,-0.068, !6164.10 LS.
     . 0, 2,-2, 2,-1, 0,  0, 0, 0, 0, 0,-0.070, 0.000, 0.000,-0.031, !6786.32 LS.
     . 0, 0, 0, 0, 1, 0,  0, 0, 0, 0, 0,-6.662, 3.611, 1.544, 2.848, !6798.38 LS.
     . 0, 0,-1, 1,-1, 8,-12, 0, 0, 0, 0,-0.120, 0.060,-0.032,-0.064/ ! 241.15 Pl.


!			ARGUMENTS

      C=57.2957795D0		! degres/radians
      CS=1.d0/(1000.d0*365.2422)! radians par 1000ans ==> radians par jour
      DPT=2.*3.14159265d0
!					Arguments pour termes luni-solaires
!					(ref.: IERS Standards (1992), p.32)

      	AP(1)=134.962 9814d0/C	! l		! radians
      	AP(2)=357.527 7233d0/C	! l'
      	AP(3)= 93.271 9103d0/C	! F
      	AP(4)=297.850 3631d0/C	! D
      	AP(5)=125.044 5222d0/C	! Omega

      	AD(1)= 13.064 9930d0/C			! radians/jour
      	AD(2)=  0.985 6003d0/C
      	AD(3)= 13.229 3502d0/C
      	AD(4)= 12.190 7491d0/C
      	AD(5)= -0.052 9538d0/C
!					Termes planetaires (memes unites)
!					(ref.: Kinoshita & Souchay (1990), 
!					Cel. Mech. vol. 48, p. 243)
	AP(6)= 3.176 146697d0	! LVe
	AP(7)= 1.753 470314d0	! LE
	AP(8)= 6.203 480913d0	! LMa
	AP(9)= 0.599 546497d0	! LJu
	AP(10)=0.874 016757d0	! LSa
	AP(11)=0.d0		! pa

	AD(6)=10213.285 546d0*CS
	AD(7)= 6283.075 8492d0*CS
	AD(8)= 3340.612 4315d0*CS
	AD(9)=  529.690 9651d0*CS
	AD(10)= 213.299 0954d0*CS
	AD(11)=   0.243 8175d0*CS

      	T=DMJD-51544.5D0
	U=0

	do 264 I=1,NT

	H=0
	do 262 LT=1,11
  262 	H=H+iarg(I,LT)*(AP(LT)+AD(LT)*T)
      	H=DMOD(H,DPT)
	U=U+TRI(I) * (am(I,Kpar,1)*dsin(H)+am(I,Kpar,2)*dcos(H))
  264	continue

	AL(1,1)= -0.07		! EOP(IERS) 97 C 04, 1992-96
	AL(2,1)= -0.24
	AL(1,2)=  0.10
	AL(2,2)=  0.04

	W=DPT*T/433.
	H=DMOD(W,DPT)

	if(kpar.eq.1)	THEN
        U= U + TFCN*(AL(1,1)*DSIN(H) + AL(2,1)*DCOS(H)) 	! FCN 
	U= U + TRATE*(-2.99)*(DMJD-51544.5)/365.25d0	  	! Precession
	U= U + TCONST*(-43.1)     				! dPsi_0

			ENDIF

	if(kpar.eq.2)	THEN
        U= U + TFCN*(AL(1,2)*DSIN(H)+ AL(2,2)*DCOS(H)) 		! FCN
	U= U + TRATE*(-0.24)*(DMJD-51544.5)/365.25d0		! Obliquity rate
	U= U + TCONST*(-5.1)      				! dEps_0

			ENDIF

	CEPIERS96= - U    	!   De cette facon, la correction CEPIERS
!			    est a AJOUTER pour liberer les coordonnees du pole
!			    celeste de l'erreur exprimee par le modele.

 1000 RETURN                                                               
      END                                                                

