subroutine ajmjd(mjdo,fmjdo,dt,mjdn,fmjdn)
      implicit real*8 (a-h,o-z)
c.......................................................................
c
c  function: ajmjd is for adjusting a modified julian date mjd, fmjd.
c        mjdo, fmjdo are the old values and mjdn, fmjdn are the outputs
c        or new values. dt, given in seconds, can be + or - and up to
c        86400 seconds. The purpose of this routine is to assure
c        that 0.le.fmjd.lt.1.0d0 at all times.
c                                                 Ben Remondi
c.......................................................................
      if(dabs(dt).gt.86400.0d0) stop ' "Ajmjd" dt .GT. 86400 '
      mjdn=mjdo
      fmjdn=fmjdo+dt/86400.0d0
      if((0.0d0.le.fmjdn).and.(fmjdn.lt.1.0d0)) go to 200
      if(fmjdn.ge.1.0d0) go to 100
      fmjdn=fmjdn+1.0d0
      mjdn=mjdn-1
      go to 200
  100 fmjdn=fmjdn-1.0d0
      mjdn=mjdn+1
  200 continue
      return
      end