real*8 function elong( jd, ra, dec )
!
!     Given the apparent right ascension and declination (degrees)
!     of an  object at time jd (Julian Day, UT), return the elongation
!     (angular distance) of the object from the apparent Sun.
!
!     B. Knapp, 1996-01-29, 2001-01-03, 2001-04-24 (i*4)
!
C
C     RCS DATA
C     
C     $Header$
C     
C     $Log$
C
!
      implicit none
!
!     Input:
      real*8 jd, ra, dec
!
!     Constants:
      real*8 D2R
      parameter (D2R = 3.14159265358979324d0/180.d0)
      integer*4 SUN, APPARENT, EQUATORIAL, SPHERICAL
      parameter (SUN=0, APPARENT=2, EQUATORIAL=1, SPHERICAL=1)
!
!     Local variables:
      real*8 pv(6)
      integer*4 status

!     Functions, Subroutines
      real*8 angdst
      external ephem, angdst
!
!
!     Get the apparent coordinates of the sun
      call ephem(jd, SUN, APPARENT, EQUATORIAL, SPHERICAL, pv, status)
!
!     Compute the elongation
      elong = angdst(ra*D2R, dec*D2R, pv(1)*D2R, pv(2)*D2R)/D2R
      return
      end