* Last processed by NICE on 12-Jun-2000 15:53:00
* Customized for :  IEEE, LINUX, UNIX, MOTIF, F77
      SUBROUTINE DPOINL(XV,A,DERIV)
C----------------------------------------------------------------------
C POINT
C	Compute the derivatives of the pointing function
C	Dimensionned for MVAR or KVAR
C V2.0
C	Changed sign of excentricity corrections
C----------------------------------------------------------------------
      INCLUDE 'size.inc'
      REAL*8 XV(3),A(MVAR),DERIV(MVAR)
      REAL*8 AZ,EL,COSEL,SINEL,COSAZ,SINAZ
*
      AZ=XV(1)
      EL=XV(2)
      COSEL=COS(EL)
      SINEL=SIN(EL)
      COSAZ=COS(AZ)
      SINAZ=SIN(AZ)
      IF (XV(3).EQ.0) THEN
         DERIV( 1)=-COSEL
         DERIV( 2)= 0
         DERIV( 3)=-1.0/SQRT(MAX(1D-37,1.0D0-(A(3)/COSEL)**2))
         DERIV( 4)= -COSAZ*SINEL
         DERIV( 5)= SINAZ*SINEL
         DERIV( 6)= SINEL
         DERIV( 7)= 0
         DERIV( 8)= 0
         DERIV( 9)= 0
         DERIV(10)= 0
         DERIV(11)= -SINAZ*COSEL
         DERIV(12)= -COSAZ*COSEL
         IF (KVAR.LE.12) RETURN
         DERIV(13)= SIN(2.D0*AZ)*COSEL
         DERIV(14)= COS(2.D0*AZ)*COSEL
         DERIV(15)= 0
         DERIV(16)= 0
      ELSE
         DERIV( 1)= 0
         DERIV( 2)=-1
         DERIV( 3)= -SINEL*A(3)/
     $   SQRT(MAX(1D-30,1.0D0-SINEL**2/(1.0D0-A(3)**2)))/
     $   SQRT(MAX(1D-30,(1.0D0-A(3)**2)**3))
         DERIV( 4)=SINAZ
         DERIV( 5)=+COSAZ
         DERIV( 6)= 0
         DERIV( 7)= 1.D0/TAN(EL)
         DERIV( 8)= DERIV(7)**3
         DERIV( 9)= -SINEL
         DERIV(10)= -COSEL
         DERIV(11)= 0
         DERIV(12)= 0
         IF (KVAR.LE.12) RETURN
         DERIV(13)= 0
         DERIV(14)= 0
         DERIV(15)= SIN(2.D0*EL)
         DERIV(16)= COS(2.D0*EL)
      ENDIF
      END